The Natural History Museum Consultancy Report Client: The Department for the Environment, Food and Rural Affairs (DEFRA) TRENDS IN CETACEAN STRANDINGS AROUND THE UK COASTLINE AND MARINE MAMMAL POSTMORTEM INVESTIGATIONS FOR THE YEAR 2001 (CONTRACT CRO 238) Authors: The Natural History Museum, London The Institute of Zoology, London The Scottish Agricultural College, Inverness For the attention of: Stacey Hughes May 2002 Report No. ECM 516F00/02 NHM Consulting Environment: Coastal & Marine Sector Tel: +44 (0) 207 942 5636 The Natural History Museum, Cromwell Rd, London SW7 5BD, U.K.
Transcript
The Natural History Museum
Consultancy ReportClient: The Department for the Environment, Food and Rural Affairs (DEFRA)
TRENDS IN CETACEAN STRANDINGS AROUNDTHE UK COASTLINE AND MARINE MAMMAL
POSTMORTEM INVESTIGATIONS FORTHE YEAR 2001 (CONTRACT CRO 238)
Part A: Trends in cetacean strandings on the UK coastlinePart A: Trends in cetacean strandings on the UK coastlinefor the year 2001 for the year 2001 ................................................................................. 6
Introduction .............................................................................. 6Results ...................................................................................… 8Distribution of cetacean species ............................................… 11
Part B: UK marine mammal post-mortem investigationsPart B: UK marine mammal post-mortem investigationsFor the year 2000 For the year 2000 ..............................................................................…. 29
Introduction .............................................................................. 29Results .................................................................................... 31Causes of death ..................................................................….. 31
By-catch ...................................................................... 31Physical trauma .......................................................…. 32Infectious disease mortality .....................................…. 34Starvation ................................................................…. 35Live-stranding ..........................................................… 36Tumours ………………………………………………….. 36Novel liver disease………………………………………... 36Other causes of death .............................................…. 36Causes of seal mortality ..........................................….. 37Causes of mortality in marine turtles …………………… 37
The Natural History Museum 2
Publications for the year 2001 Publications for the year 2001 .............................................….......... 45
GENERAL INTRODUCTION TO THE JOINT REPORTGENERAL INTRODUCTION TO THE JOINT REPORT
This report is based on research conducted under contract to the Department forthe Environment, Food and Rural Affairs (DEFRA) between 1st January and 31st
December 2001 (Contract no’s CRO177, CR0178, CRO179 & CRO238). Thefollowing organisations were contracted or subcontracted under theseagreements:
Organisation Contract no.
The Natural History Museum (NHM) CRO178, CRO238Cromwell RoadSouth KensingtonLondonSW7 5BDTel: 020 7942 5155Fax: 020 7942 5572
Institute of Zoology (IoZ) CR0177, CRO238Regent`s ParkLondonNW1 4RYTel: 020 7449 6691Fax: 020 7586 1457
The authors involved in the production of this report are as follows:
R. C. Sabin, P. D. J. Chimonides and C. Spurrier (NHM)P. D. Jepson and R. Deaville (IoZ)A. Reid and T. Patterson (SAC)
The Natural History Museum 4
ABSTRACTABSTRACT
Data compiled by The Natural History Museum provide a detailed overview ofnumbers of cetacean strandings (by species) for 2001, and are compared to datafor previous years. This data continues to provide a valuable and historical insightinto the temporal and geographical patterns of cetacean strandings in the UnitedKingdom. The data show that 549 cetaceans were reported stranded in 2001, thehighest number ever recorded within the UK since the NHM began keepingrecords in 1913. The previous highest figure was 421 in the year 2000. However,the frequency and distribution of cetacean strandings are thought to be closelycorrelated to strong onshore winds, and the severe winters of 2000 and 2001 areconsidered likely to have influenced to some degree the high number of cetaceanstrandings recorded in those years. Furthermore, the post-mortem findings forcetacean strandings in 2001 are not dissimilar to findings in previous years of thestrandings project. The lack of any mass mortality events or cases of morbillivirusinfection in any marine mammal species in 2001 are also consistent with findingsin recent years.
Three larger cetacean species seen less commonly in UK waters were recorded in2001. A humpback whale (Megaptera novaeangliae) stranded alive on the Kentcoast in March, and in September a second animal was reported stranded in theBay of Stoer, Highland. These are the first records of humpback whalesstranding in the UK for 16 years. A sei whale (Balaenoptera borealis), strandedat Cockerham Sands, Morecambe Bay in September 2001 was the first time thisspecies had been recorded since 1990. Similarly, in October 2001, a killer whale(Orcinus orca) stranded at Speke, Merseyside, the first record of this species inthe UK since 1997.
A number of smaller cetaceans were found stranded in fresh water coursesaround the UK in 2001, most notably, a bottlenose dolphin (Tursiops truncatus)seen swimming in the Thames for almost three weeks during June/July.Examination of the skeletal remains of the animal at the NHM showed extensivepathological deformation of the skull and vertebral column.
The most commonly stranded cetacean species in the UK during 2001 was theharbour porpoise (Phocoena phocoena) of which 259 were recorded. The mostcommon cause of mortality of the 118 UK-stranded harbour porpoisesexamined at post-mortem in 2001 was attack from bottlenose dolphinsaccounting for the death of 28 individuals. This was also the most commoncause of mortality in UK-stranded harbour porpoises in 2000. Most casesoccurred in north east Scotland and Wales where porpoises share sympatricdistributions with resident bottlenose dolphin populations, although the firstcases of this phenomenon in England were recorded in 2001 with single casesoccurring in Devon and Cornwall. Fatal attack from bottlenose dolphins hasconsistently been the most common cause of death in stranded harbourporpoises in Scotland during the 1990s. However, it is only in the period 1999-2001 that the number of harbour porpoises killed by bottlenose dolphins hasincreased significantly in west Wales.
The Natural History Museum 5
There were 10 cases of by-catch diagnosed in harbour porpoises that actuallystranded in England and Wales during 2001, and only one in Scotland. Thisappears to represent a continuing declining trend in the proportion of strandedporpoises being diagnosed as by-catches in England and Wales since theypeaked in the mid-1990s. Numbers of by-catches in harbour porpoises andother stranded cetaceans have always been low in Scottish waters. Externallesions in most harbour porpoise by-catches were consistent with entanglementin monofilament-type gillnet. By-catch was the most common cause of mortalityof 35 UK-stranded common dolphins (Delphinus delphis) examined in 2001, andall 20 individuals stranded in Southwest England during the winter. This seasonalpattern of common dolphin strandings and by-catches in SW England is highlyconsistent with findings in previous years, although the number of commondolphin strandings and by-catches in 2001 are slightly higher. This winterdistribution of common dolphin by-catches also consistently overlaps with thewinter mid-water pelagic trawl fishing off the SW Coast of England and isthought to be causally related. Interestingly, the age structure of strandedcommon dolphin by-catches in SW England between 1990-2001 appears biasedtowards adults rather than juveniles and is in clear contrast to the predominanceof juveniles in harbour porpoise by-catches stranded in England and Walesduring the same period. This difference in age structure between commondolphin and harbour porpoise by-catches may indicate that a degree of learningis involved in avoidance of gillnets that does not necessarily apply to commondolphins suspected to have been by-caught in mid-water pelagic trawl fisheries.
A range of infectious diseases due to parasitic, bacterial and fungal infectionswere recorded predominantly in harbour porpoises during 2001, many of whichwere considered to have caused the death of the animal. These findings areconsistent with those in harbour porpoises in previous years. Analysing 11 yearsof post-mortem data reveals that a significantly greater proportion of infectiousdisease mortality occurred in harbour porpoises stranding during the winter(October-March) than in summer (April-September) in England and Walesbetween 1990-2001. This is probably due to the colder sea temperatures inwinter having an additional stressing effect on porpoises in UK waters.
During 2001, research on levels of contaminants in UK stranded cetaceans(particularly harbour porpoises) was ongoing with tissue samples being sent tothe CEFAS Burnham Laboratory, Essex, for analysis of organochlorines, heavymetals, butyltins and polybrominated flame retardants. Statistical investigationsinto potential relationships between such contaminants and health status ofstranded harbour porpoises are planned for 2002 utilising this expandingdataset.
The Natural History Museum 6
Part APart A
TRENDS IN CETACEAN STRANDINGS AROUND THETRENDS IN CETACEAN STRANDINGS AROUND THECOASTLINES OF THE UNITED KINGDOM FOR 2001COASTLINES OF THE UNITED KINGDOM FOR 2001
IntroductionIntroduction
The Natural History Museum (NHM) has been recording and investigatingincidents of cetacean strandings from around the coasts of the United Kingdomfor more than 100 years. The work was formalised in 1913 when an agreementwas made with the British Board of Trade, giving the Museum first claim to thecarcasses of dead, stranded cetaceans for scientific investigation and subsequentincorporation into the Museum’s research collections.
Since 1990, the work has been funded by the Department of the Environment,Transport and the Regions (DETR), now the Department for the Environment,Food and Rural Affairs (DEFRA). Under the terms of the current contract withDEFRA, the Natural History Museum co-ordinates and investigates cetaceanstrandings in the United Kingdom as part of a partnership with the Institute ofZoology (IoZ), London, and the Scottish Agricultural College Veterinary ScienceDivision (SAC), Inverness.
All strandings information recorded by the NHM since 1913 has been enteredonto computer database at the Museum, allowing the rapid extraction, detailedanalysis and interpretation of the data.
The Natural History Museum continues to use the knowledge and expertisegained through the UK Cetacean Strandings programme to participate in theproduction of the ASCOBANS (AA greement on the Conservation of SSmallCCetaceans OO f the BBaltic AAnd NNorth SSeas) Annual National Report. Data for the2001 report were submitted in February 2002. The NHM continues to be amember of the DEFRA Cetacean and Marine Turtle Group, which meets twiceyearly and is responsible for implementing five UK Species Action Plans forcetaceans and marine turtles.
Ten members of staff from the Natural History Museum were responsible forretrieving the carcasses of 34 cetaceans from locations around the country forpost-mortem analysis in 2001. Staff from the NHM also carried out on-siteretrieval of tissue samples from the carcasses of two cetaceans too large to betransported elsewhere for examination.
The Natural History Museum 7
The success of the UK Cetacean Strandings programme relies heavily upon theefforts of the countless numbers of individuals and organisations that makeregular reports to the NHM. The Natural History Museum continues to begreatly helped in its work by H. M. Coastguard, the Cornwall Wildlife Trust (forstrandings in Cornwall), Brixham Seawatch, Devon Wildlife Trust and theNational Marine Aquarium (for strandings in Devon), Durlston Marine Projectand Hampshire Wildlife Trust (for strandings in Dorset and Hampshire), MarineEnvironmental Monitoring (for strandings in Wales) and the Ulster Museum (forstrandings in Northern Ireland).
Plate 1. Staff from the Natural History Museum, Institute of Zoology, Marine Environmental Monitoring and UniversityPlate 1. Staff from the Natural History Museum, Institute of Zoology, Marine Environmental Monitoring and Universityof Liverpool work against the clock to undertake post-mortem analyses and collect tissue samples from a stranded killerof Liverpool work against the clock to undertake post-mortem analyses and collect tissue samples from a stranded killerwhale (whale (Orcinus orcaOrcinus orca ) in the Mersey Estuary, 9 October 2001 (SW.2001/234)) in the Mersey Estuary, 9 October 2001 (SW.2001/234).
Image: Rob Deaville, Institute of Zoology, London
The year 2001 also saw the development and launch of the Natural HistoryMuseum’s ‘UK Cetacean Strandings’ website. The website, developed with theapproval of DEFRA, presents background information about the Museum’swork, provides an historical overview of the UK Cetacean StrandingsProgramme, has a ‘Recent Events’ section detailing strandings of particularinterest, an identification guide and a searchable limited-access database whichallows visitors to the site to investigate recent reports for their area. The websitealso contains an up-to-date electronic copy of the NHM’s reporting form 136,which has now been circulated widely to UK Coastguard Stations via theReceiver of Wreck.
The Natural History Museum 8
ResultsResults
In 2001, a total of 549 reports were received by the Natural History Museumrelating to strandings of dead cetaceans, strandings and sightings of livecetaceans, reports of carcasses seen floating dead at sea and cetacean by-catch:
Table 1: Report categoriesTable 1: Report categoriesStranded, dead cetaceans 474Live-strandings 22Carcasses seen floating at sea 31Reported cetacean by-catch 6Other (unconfirmed/suspected by-catch) 16
TOTAL: 549549
Records for the year 2001 include details of at least 15 cetacean species:
Table 2: Reported cetacean strandings in the UK for 2001 by region and species Table 2: Reported cetacean strandings in the UK for 2001 by region and species
ENGLAND, WALESENGLAND, WALES& ISLE OF MAN& ISLE OF MAN
The total for the year 2001 is higher when compared with UK records for theprevious years (see Figure 1 and Table 3):
The Natural History Museum 9
Figure 1. Total number of reported UK strandings etc. 1990 to 2001 Figure 1. Total number of reported UK strandings etc. 1990 to 2001
Table 3. Numbers of all cetacean species stranded around the UK, 1991 - 2001Table 3. Numbers of all cetacean species stranded around the UK, 1991 - 2001
Strandings schemes were introduced into England and Wales in 1990 and inScotland in 1992. Improvements in recording techniques combined with asteady growth in the number of organisations and individuals reporting to theNHM, may have led to an increase in the numbers of animals recorded duringthe first half of the 1990s, but more recent years have seen reliable data comingfrom established sources (Figure 1).
Table 3 shows the totals for each species recorded from 1990 to 2001. Minorfluctuations in numbers remains a feature for most species represented acrossthis period. However, in 2001, numbers of harbour porpoise reported increasedby approximately 25%, and numbers of common dolphin by almost 100%.
Figure 2. Reported cetacean strandings etc. for England, Wales, Northern Ireland,Figure 2. Reported cetacean strandings etc. for England, Wales, Northern Ireland,the Isle of Man and Scotland, 1998 – 2001the Isle of Man and Scotland, 1998 – 2001
Figure 2, shows the reported number of cetacean strandings etc. for England,Wales, Northern Ireland, the Isle of Man and separately for Scotland. Althoughthe number of reports for Scotland has remained fairly constant over the pastfour years, there is a marked increase in the English and Welsh data. Thisincrease is primarily the result of higher numbers of common dolphins andharbour porpoise being reported (see Tables 2 and 3).
Map 1, shows the distribution of all cetaceans reported to the Natural HistoryMuseum in the year 2001. The general geographical distribution continues tobe similar to previous years, with concentrations of strandings found around thecoasts of Cornwall, west Wales, the Outer Hebrides and scattered along NorthSea coasts from central East Anglia to the Shetland Islands.
235249
281
413
134 137 140 136
0
50
100
150
200
250
300
350
400
450
1998 1999 2000 2001
Tota
ls
England, Wales, N. Ireland & Isle of Man Scotland
The Natural History Museum 11
Distribution of cetacean speciesDistribution of cetacean species
Balaenoptera acutorostrataBalaenoptera acutorostrata (minke whale or lesser rorqual) (minke whale or lesser rorqual)
Fourteen minke whales were reported stranded around the UK in 2001, a figurewhich is consistent with previous years (see Map 2 and Tables 2 & 4). Thedistribution pattern around the north of the UK, particularly along the North Seacoast is also comparable with recent years. The distribution and dates ofstranding illustrated by the data support field observations made by the SeaWatch Foundation. Their observations show groups of minke whales in coastalwaters of the northern North Sea primarily from May to October each year(Evans, 1995; p.12).
Table 4. Table 4. Balaenoptera acutorostrataBalaenoptera acutorostrata – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/81f 14/04/2001 Fife F 4.90SW.2001/100 08/05/2001 Northumberland F -SW.2001/120 10/06/2001 Northumberland M 5.20SW.2001/122a 11/06/2001 Orkney - 7.00 (approx)SW.2001/128a 25/06/2001 Strathclyde - 3.50 (approx)SW.2001/138a 03/07/2001 Shetland - 4.50 (approx)SW.2001/138b 06/07/2001 Orkney M 5.70 (approx)SW.2001/139a 05/07/2001 Antrim F 5.30SW.2001/188a 10/08/2001 Cornwall - 2.90 (approx)SW.2001/193a 21/08/2001 Dumfries - -SW.2001/250a 08/11/2001 Western Isles F -SW.2001/253a 12/11/2001 Highland - 4.70 (approx)SW.2001/265b 02/12/2001 Strathclyde - -SW.2001/277 17/12/2001 Cornwall - 2.74 (approx)
Growth parameters established for North Atlantic populations of minke whalesgive the mean length at sexual maturity for males at 6.75 metres and females at7.2 metres (Christensen, 1980). Using these parameters, the data in Table 4suggests that many of the minke whales stranded around the UK in 2001 maynot have reached sexual maturity.
On the 28th September 2001, a sei whale (SW.2001/219) measuring 14.25 metresin length was found stranded alive at Cockerham Sands, Lancashire (see Plates 2-3& Map 3). Despite the efforts of British Divers Marine Life Rescue (BDMLR), theanimal died shortly after discovery. Staff from the NHM attended the strandingand retrieved samples of baleen and soft tissues.
Sei whales are thought to inhabit the deep Atlantic waters from Iceland andNorway south to the Iberian Peninsula, and are seen most frequently betweenIceland and Greenland, and in the mid-Atlantic west of Ireland (Evans, 1995; p.9).
The Natural History Museum 12
In the UK since 1913, only thirteen examples of this species have been recorded(see Table 5).
Table 5. Table 5. Balaenoptera borealisBalaenoptera borealis – UK strandings, 1913-2001 – UK strandings, 1913-2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.1914/44 21/09/1914 Caithness - 13.11SW.1925/3 17/02/1925 Monmouthshire M 14.76SW.1925/7 07/05/1925 Isle of Man F 14.63 (approx)SW.1929/30 03/10/1929 Orkney - 14.73SW.1948/21a 12/09/1948 Essex - 4.88SW.1949/17 20/07/1949 Aberdeenshire - -SW.1965/21 04/09/1965 Western Isles - -SW.1971/7 16/07/1971 Norfolk - 13.41SW.1975/9 16/05/1979 Western Isles F 12.80SW.1980/30 05/09/1980 Lancashire - 7.21SW.1989/62 03/08/1989 Cornwall - 14.02SW.1990/90b 25/10/1990 Western Isles F 13.72SW.2001/219 28/09/2001 Lancashire F 14.25
The majority of animals recorded are within the range of total lengths given formature adult animals, i.e. 13.6 to 14.9 metres (Evans, 1995 and Fraser, 1969).The length of the sei whale stranded at Essex in 1948 (SW.1948/21a) is consistentwith neonatal length for this species.
Migrations and movements of sei whales are not as well understood as those ofthe larger baleen whales. It is thought that animals on the eastern side of theNorth Atlantic off the Bay of Biscay and north west Africa, probably move towardsNorway and more northern waters during the summer months (Gambell, 1985; p.158-159). The dates of stranding listed in Table 5 suggest that this may indeed bethe case.
Plate 2. A female sei whale (Plate 2. A female sei whale (Balaenoptera borealisBalaenoptera borealis), 14.25), 14.25metres long, stranded at Cockerham Sands, Lancashire, 28metres long, stranded at Cockerham Sands, Lancashire, 28September 2001 (SW.2001/219). Note the dark baleenSeptember 2001 (SW.2001/219). Note the dark baleenplates edged with pale fringes, characteristic of this species.plates edged with pale fringes, characteristic of this species. Plate 3. Tongue and baleen of sei whale.Plate 3. Tongue and baleen of sei whale.
Photographs: P.J. Chimonides, the Natural History Museum, London.
On the 21st March 2001, a male humpback whale (SW.2001/60), 10.66 metresin length, was found stranded alive on the beach at Pegwell, Sandwich Bay,Kent (see Map 4 and Plates 4 and 5). The stranding was initially attended bymembers of the RSPCA and BDMLR, but it was soon ascertained throughveterinary examination that the animal was very emaciated and too weak torefloat. The animal was later euthanased.
In September 2001, a second humpback whale (SW.2001/205b) was foundstranded in the Bay of Stoer, Highland. Unfortunately, no other details areavailable about this animal.
Since 1913 in the UK, only four strandings of humpback whales have beenrecorded, all in the past 20 years (see Table 6). The Kent stranding representsthe most southerly record of this species in the UK, and the first record inEngland for at least 100 years.
Table 6. Table 6. Megaptera novaeangliaeMegaptera novaeangliae – UK strandings, 1913-2001 – UK strandings, 1913-2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.1982/38 16/10/1982 Glamorgan M 8.66SW.1985/42 23/08/1985 Highland F 5.99SW.2001/60 21/03/2001 Kent M 10.66SW.2001/205b 07/09/2001 Highland - -
The testes of the Kent humpback were examined by staff from the Institute ofZoology (IoZ), London. The examination revealed that the animal was notsexually mature, and placed its age at between one and three years. Otherstudies of humpback whales have suggested that the average length at birth is 4to 5 metres, and mean length at sexual maturity is 11.58 metres for males and12.09 metres for females (Winn and Reichley, 1985; p.242). The length rangegiven for fully mature adult humpback whales is 11.5 to 15 metres (Evans,1995; p.7). The length data in Table 6 suggests that three of the four animalsrecorded by the NHM were juvenile or very young individuals.
Three of the four humpbacks recorded in Table 6 stranded in the latter half ofthe year – August to October. Sightings data report humpback whales incoastal north European waters mainly from April to September, but othersightings have extended into December and January (Evans, 1995; p.7). Thesightings are thought to be linked to the annual migrations of humpback whalesto their northern feeding grounds in Arctic and sub-Arctic waters (Winn andReichley, 1985; p.249). These migrations in the eastern North Atlantic bringthem into UK coastal waters, leading to sightings and strandings primarily offthe western coasts.
The Natural History Museum 14
Their rarity in British and Irish waters and long absence from the NHM’sstrandings records until comparatively recently, may perhaps be indicative of arecovery in humpback numbers. Fraser (1969; p.11) notes that commercialwhaling companies operating in British waters during the first half of thetwentieth century did take humpback whales as part of their catch.
Plate 4 (front view) and Plate 5 (side view). A male humpback whale (Plate 4 (front view) and Plate 5 (side view). A male humpback whale (Megaptera novaeangliaeMegaptera novaeangliae), 10.66 metres long,), 10.66 metres long,stranded alive at Pegwell, Sandwich Bay, Kent, 21 March 2001 (SW.2001/60).stranded alive at Pegwell, Sandwich Bay, Kent, 21 March 2001 (SW.2001/60).
In 2001, one hundred and twenty six common dolphins (Delphinus delphis)were reported to the Natural History Museum (Map 5). This figure includes theremains of four very decomposed animals recovered by bottom trawlers on the26 January and 2 February, near the Eddystone Lighthouse off the Devon coast(species identified by examination of skulls; SW.2001/24c-d and SW.2001/26b-c). Also included in this figure are sixteen dead common dolphins found floatingon the 20 November approximately sixteen miles off Looe, Cornwall(SW.2001/256b.1-13; N.B. independent reports received from the crews of twosmall, local fishing vessels working in the area).
The total for 2001 represents an increase of almost 100% on the previous year(see Table 3), and is the highest figure recorded since the by-catch-related massmortality event of 1992, described by Kuiken et al (1994; p. 81-89).
In the first three months of 1992, one hundred and eighteen common dolphinswere reported stranded on the coast of Cornwall and Devon. Figure 3 showsthe breakdown of figures by month and region for 2001; the majority ofcommon dolphins reported in 2001 were found stranded around the south westof England, continuing the distribution trend seen in previous years. Althoughthe numbers of animals reported monthly were comparatively low for eachregion represented, and are not comparable with data for 1992 (Jan-Mar 1992= 118; Jan-Mar 2001 = 59), both March and November show a marked increasefor the south west of England.
The Natural History Museum 15
Figure 3. Strandings of common dolphin by month for 2001Figure 3. Strandings of common dolphin by month for 2001
0
2
4
6
8
10
12
14
16
18
20
Jan Feb Mar Apr May Jun Jul Aug Sep O c t Nov Dec
Cornwall Devon Rest of England Wales Scotland
Previous reports have commented on the possible effects of the annual pelagicpurse-seine fishing activities around the south west of England which arebelieved to commence at the beginning of September, and the seasonalmovements of common dolphin populations bringing large numbers of theminto the English Channel. Data collected by the NHM supports otherobservational data, suggesting that the critical period for this interactionbetween humans and dolphins is from September/October to March/April. Ofthe thirty five common dolphins retrieved for post mortem examination in 2001,twenty had by-catch diagnosed as cause of death (see Tables E and F in Part Bof this report). This represents approximately 16.5% of all common dolphinsreported that year. However, since the publication of the paper by Kuiken et al,in 1994, awareness of the by-catch issue and its possible effects on dolphinpopulations has become widespread amongst cetacean workers around the UK.Using his own observations and the published observations of others, Kuiken(1994; 84) classified distinct categories of lesions which were suggestive ofcapture in fishing gear:
1. Traumatic lesions specific for capture in fishing gear:(a) cleanly cut-off fin or tail fluke(b) incision wound in abdominal cavity(c) circumscribing skin abrasions on beak, fin or tail fluke(d) multiple evenly spaced parallel incision wounds in the skin
2. Traumatic lesions not specific for capture in fishing gear:(a) subcutaneous, intramuscular or subpleural haemorrhage(b) skull fracture
The Natural History Museum 16
These two general categories have been widely adopted and the physicalappearance of the lesions listed are now recognised by many workers. As aresult, the Natural History Museum receives many reports of dolphins whosestate of preservation may not make them entirely suitable for post mortemanalysis, but whose condition remains complete enough for possible by-catch-related lesions to be visible. The Museum records these reports on its databaseas ‘unconfirmed by-catch’, i.e. not established by post mortem or through directobservation of capture. The Museum has recently started to receive digitalimages of these animals, allowing for wider and more informed assessments tobe made. Plate 6, is an extreme example of such a record:
Plate 6. SW.2001/269: common dolphin, Gileston beach, Barry, Glamorgan, 9 December 2001. Rear portion of body ofPlate 6. SW.2001/269: common dolphin, Gileston beach, Barry, Glamorgan, 9 December 2001. Rear portion of body ofa common dolphin showing cleanly cut edges. Still visible are the remains of an incision wound made along the ventrala common dolphin showing cleanly cut edges. Still visible are the remains of an incision wound made along the ventralmidline.midline.
Photograph: Rod Penrose, Marine Environmental Monitoring.
Other images regularly show entanglement in discarded fishing nets, trauma tothe tip of the rostrum or smashing of the lower jaw, cut-off pectoral flippers ortail flukes and evenly spaced incision wounds to the skin. The number ofunconfirmed by-catch records for common dolphins in 2001, using criteriadescribed in Kuiken et al (1994) is fifteen, all from the south west of England. Itis also believed by observers that the sixteen common dolphins seen floatingdead approximately sixteen miles off Looe, Cornwall on the 20 November 2001,may represent a single by-catch event. If these two figures are added to thenumber of confirmed by-catches, the total (n = 51) represents approximately40% of common dolphins recorded. Map 5a, shows records of commondolphins categorised as by-catch (suspected and confirmed) and those seenfloating at sea for 2001. Map 5b, shows the distribution of all common dolphinsreported from 1997 to 2001. Map 5c, shows records of common dolphinscategorised as by-catch (suspected and confirmed) and those seen floating atsea from 1997 to 2001.
Figure 4, shows the cumulative monthly totals of common dolphins strandedfrom 1997 to 2001. The data indicate the presence of common dolphins aroundthe UK throughout the year, but shows an increase in overall numbers fromOctober to April. The peak period for strandings is shown as January to March.The strandings data for this period does not accord with recent UK sightingsdata (see Evans, 1995), where the peak period given is July to October.
The Natural History Museum 17
Figure 4. Cumulative monthly totals of common dolphins stranded, 1997-2001Figure 4. Cumulative monthly totals of common dolphins stranded, 1997-2001
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
9 0
Jan F e b M a r A p r M a y Jun J u l A u g S e p Oct N o v D e c
month
coun
t
Figure 5, shows length data by month for common dolphins recorded during theperiod 1997-2001. Neonatal length is given as 80 to 90 centimetres by mostauthors (Evans, 1994; p.204)
Geographical variation in maximum length of fully mature adults has been notedfor this species (Evans, 1994), but the range given for the eastern North Atlanticis 1.6 to 2.6 metres (Evans, 1995).
Figure 5. Common dolphin lengths by month, 1997-2001
Only three strandings were recorded as common/striped dolphin indeterminatein 2001 (Tables 2 & 3). Numbers of these records vary each year dependingupon the condition and accessibility of specimens. In 2001, all three specimenswere described as very decomposed. In terms of general body size and shape,the common and striped dolphin are quite similar. Once decomposition orscavenging has destroyed identifiable external characteristics, distinguishingbetween the two species can be difficult. Fortunately, the common dolphin hastwo well-defined palatal grooves on the ventral surface of the rostrum. Thesecan usually be identified through touch, by applying gentle pressure to the roofof the mouth.
Globicephala melasGlobicephala melas (long-finned pilot whale) (long-finned pilot whale)
Twenty seven long-finned pilot whales were recorded in 2001 (Map 6). Thetotal includes three animals seen floating dead approximately sixteen miles offLooe, Cornwall on the 20 November, in the same area as sixteen commondolphins also seen floating dead. It is possible that the three pilot whale deathsmay also be related to by-catch. The distribution of long-finned pilot whalesobserved for 2001 is comparable with recent years, but the number representsan increase of approximately 30% (see Table 3). Table 7, shows long-finnedpilot whale strandings for the year as two distinct groups – one located aroundthe south west coast of England (n = 21) and the other around the west andnorth coasts of Scotland (n = 6).
Table 7. Table 7. Globicephala melasGlobicephala melas – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
The distribution data for 2001 support the sightings data for this species in UKwaters (see Evans, 1995).
The range of lengths given for adult pilot whales are 5.0 to 6.1 metres for malesand 4.05 to 4.72 metres for females (Evans, 1994; p.250). Neonatal length isgiven as 1.75 to 1.78 metres (Evans, 1995; p. 15). Table 7, suggests that justover half of those animals whose lengths have been recorded were adults, withthe rest being very young or juveniles. One animal was found stranded alive onthe Devon coast near Exeter on 14 October – a newborn female, 1.78 metreslong (Plate 7). The animal was refloated twice but did not return successfullyand was later euthanased.
Plate 7. Plate 7. Globicephala melasGlobicephala melas, newborn/very young female, 1.78 metres long, found, newborn/very young female, 1.78 metres long, foundon the Devon coast near Exeter, 14 October 2001 (SW.2001/238).on the Devon coast near Exeter, 14 October 2001 (SW.2001/238).
Six reports were received for Risso’s dolphin in 2001 (Table 2 and Map 7). Thisfigure is lower than that for the year 2000, but represents an expected annualfluctuation for this species (see Table 3). The distribution data shown in Table 8are consistent with sightings data for the UK, as are the dates of stranding (seeEvans, 1995; p.17). The range of lengths given for adults of this species is 2.8to 3.3 metres, with a neonatal length of 1.2 to 1.5 metres.
Table 8. Table 8. Grampus griseusGrampus griseus – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/35c 14/02/2001 Orkney F 2.61SW.2001/109c 19/05/2001 Western Isles M 2.10SW.2001/146b 10/07/2001 Orkney - 2.70 (approx)SW.2001/186b 06/08/2001 Western Isles F 2.40 (approx)SW.2001/211 20/09/2001 Ceredigion F 3.14SW.2001/254 17/11/2001 Gwynedd M 1.52 (approx)
Only four records were received for the white-sided dolphin in 2001, all fromScotland (Tables 2 & 9). This species shows an expected annual fluctuation innumbers (Table 3). Distribution data (Map 8) and dates of stranding areconsistent with sightings data, i.e. seen around the Northern Isles and west ofthe Outer Hebrides in large numbers from July to September (see Evans, 1995;p.17). Map 8a, shows cumulative distribution data for the period 1997 to 2001.The range of lengths given for adult white-sided dolphins is 2.0 to 2.8 metres(Evans, 1995).
Table 9. Table 9. Lagenorhynchus acutusLagenorhynchus acutus – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/87b 26/04/2001 Highland M 2.52SW.2001/146c.1 10/07/2001 Shetland M 2.50SW.2001/146c.2 10/07/2001 Shetland F 2.24SW.2001/199b 28/08/2001 Shetland M 2.57
Fourteen records were received for this species in 2001, all from Scotland(Map 9). This figure is comparable with totals for previous years (Table 3) butincludes a mass stranding of eight animals at Lerwick, Shetland, 21 February2001 (SW.2001/36d.1-.8: no sex/length data reported so omitted fromTable 10).
Table 10. Table 10. Lagenorhynchus albirostrisLagenorhynchus albirostris – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/162a 17/07/2001 Grampian F 2.45SW.2001/205c 08/09/2001 Western Isles - 2.17SW.2001/212b 22/09/2001 Orkney F 1.28SW.2001/268c 04/12/2001 Grampian M 1.64SW.2001/268e 06/12/2001 Highland M 1.72
Map 9a, shows cumulative distribution data for the period 1997 to 2001. Thestrandings can be seen extending down the North Sea coast and along theChannel coast. This supports recent sightings data (Evans, 1995). The range oflengths given for adult white-beaked dolphins is 2.5 to 2.7 metres, with aneonatal length of 1.2 to 1.6 metres (Evans, 1995; p.17).
Two animals were recorded in 2001 where identification was only possible togenus (Tables 2 & 3). External similarities between L. acutus and L. albirostrismake it difficult to distinguish between species if presented with a decomposingcarcass. Without close examination of skeletal morphology, identificationbeyond genus is problematic.
The Natural History Museum 21
Map 10, shows the position of the two strandings recorded in 2001. Map 10a,shows the distribution of all records determined as Lagenorhynchus speciesindeterminate for the period 1997 to 2001. Map 10a, also shows thecumulative distribution for L. acutus and L. albirostris for the same period.Inferences regarding the possible identification of Lagenorhynchus speciesindeterminate records can be made based upon the known distribution of thewhite-sided and white-beaked dolphin.
Only one killer whale was reported to the NHM in 2001 (Tables 2 & 3), the firststranding to be recorded in the UK since 1997. The animal, a male, was foundstranded alive on a sandbar near Speke Airport, Mersey Estuary on 9 October2001 (SW.2001/234). Despite attempts to save the whale by the RSPCA andBDMLR, it later died. The stranding was attended by staff from the NHM, IoZ,Marine Environmental Monitoring and University of Liverpool (see Plates 1 & 8).Post-mortem examination was carried out at the site, which was only accessible byhelicopter. Extensive sampling was undertaken, and sections of the animal(including the complete lower jaw) were taken back to the NHM for furtheranalysis. Parasites were also retrieved from the animal. The animal was observedto be very emaciated and the dentition almost completely worn to the gum-line.
Plate 8. Adult male killer whale found stranded alive in the Mersey Estuary, 9 OctoberPlate 8. Adult male killer whale found stranded alive in the Mersey Estuary, 9 October2001 (SW.2001/234).2001 (SW.2001/234).
Photograph: Institute of Zoology, London.
Since 1913, eighty three records of killer whale strandings have been receivedby the NHM. Map 11, shows the distribution of all UK killer whale strandingsfrom 1913 to 2001 (also included are data from the Republic of Ireland). Moststrandings occur around the north and west coasts of Scotland, but Map 11shows that killer whales have washed ashore along the North Sea and EnglishChannel coasts, as well as west Wales and the north west coast of England.Killer whales are widely distributed in the North Atlantic and sightings arerecorded in all months of the year in UK waters (Evans, 1995; p.15). These dataare supported by the NHM strandings records.
The Natural History Museum 22
The range of lengths given for adult killer whales is 4.5 to 6.6 metres for femalesand 5.7 to 9.5 metres for males. Neonatal length is given as 2.06 to 2.50metres (Evans 1995; Dahlheim and Heyning, 1999; p. 287). Of the eighty threekiller whale records held by the NHM, sixty six have total length measurements.Of these, seventeen are in the range 2.36 to 3.35 metres, and can be assumedto be newborn to juvenile in age.
Stenella coeruleoalbaStenella coeruleoalba (striped or euphrosyne dolphin) (striped or euphrosyne dolphin)
In 2001, fourteen striped dolphins were reported to the NHM (Tables 2 & 3).The figure, which is comparable with recent years, includes three dead animalsfound beached together at St. Audries Bay, Somerset (SW.2001/29.1-3). Oneanimal was found stranded alive at Ilfracombe, Devon, entangled in fishing nets(SW.2001/93) and died despite several attempts to free it. The distribution ofstriped dolphin strandings for 2001 can be seen in Map 12, and is similar toprevious years (see Map 12a for 1997 to 2001). Most strandings occur alongthe western coasts of the UK. Live sightings of striped dolphins off the Atlanticseaboard of the UK are rare (Evans, 1995; p.21), but records do exist for thisspecies in coastal UK waters, mainly between July and September. Table 11,shows that strandings of striped dolphins occurred throughout the year in 2001.
Table 11. Table 11. Stenella coeruleoalbaStenella coeruleoalba – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/18 24/01/2001 Cornwall F 2.05SW.2001/25b 28/01/2001 Ceredigion - 1.70SW.2001/29.1 06/02/2001 Somerset - 1.40SW.2001/29.2 06/02/2001 Somerset - 1.40SW.2001/29.3 06/02/2001 Somerset M 1.45SW.2001/93 01/05/2001 Devon M 1.73SW.2001/128b 26/06/2001 Fife M 2.22SW.2001/181a 28/07/2001 Cornwall - -SW.2001/189 14/08/2001 Gloucestershire F 1.58SW.2001/205d 09/09/2001 Highland F 2.06SW.2001/205e 10/09/2001 Highland F 1.89SW.2001/212a 22/09/2001 Highland M 1.67SW.2001/217 27/09/2001 Devon F 1.68SW.2001/238 15/10/2001 Western Isles M 1.76
The range of lengths given for adult striped dolphins is 1.95 to 2.4 metres and1.0 metres for newborn animals (Evans, 1995; p.21).
Nine bottlenose dolphins were reported to the NHM in 2001 (Tables 2 & 3), afigure comparable to previous years. Distribution of strandings around the eastand west coasts of Scotland and Cardigan Bay, Wales, is also comparable withrecent years (Maps 13 & 13a), although 2001 saw an absence of bottlenosedolphin strandings around the south west coast of England. Sightings reportsreceived directly from Sussex, Dorset, Devon and Cornwall Wildlife Trustsrecorded the presence of this species throughout the year.
The Natural History Museum 23
One notable stranding occurred in July 2001 (SW.2001/141). A bottlenosedolphin had been observed swimming in the River Thames near Tower Bridge,London, and for a period of two weeks was monitored by the RSPCA and RiverPolice. The behaviour of the animal was a cause for concern, often seen‘resting’ on sandbars and showing signs of progressive skin blistering. Theanimal eventually died and was recovered by NHM staff and River Police forpost-mortem analysis at IoZ. Detailed skeletal investigation of the remains werecarried out at the NHM, and showed evidence of extensive pathologicaldeformity, probably associated with the age of the animal (plates 9a to 9d).
Plate 9a (top left): Adult female bottlenose dolphin (SW.2001/141), right-side view of skull. Plate 9b (top right): detailPlate 9a (top left): Adult female bottlenose dolphin (SW.2001/141), right-side view of skull. Plate 9b (top right): detailof lower jaw showing areas of bone destruction related to abscess formation. Plate 9c (bottom left): mid-thoracic regionof lower jaw showing areas of bone destruction related to abscess formation. Plate 9c (bottom left): mid-thoracic regionof vertebral column showing extreme kyphosis and scoliosis of the vertebrae. Plate 9d (bottom right): detail ofof vertebral column showing extreme kyphosis and scoliosis of the vertebrae. Plate 9d (bottom right): detail oftransverse vertebral process showing extensive remodelling of the bone.transverse vertebral process showing extensive remodelling of the bone.
Photographs: R.C. Sabin, the Natural History Museum, London
Table 12. Table 12. Tursiops truncatusTursiops truncatus – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/75a 02/04/2001 Highland M 3.14SW.2001/111a 23/05/2001 Highland F 3.30SW.2001/114 29/05/2001 Ceredigion F 3.24SW.2001/141 08/07/2001 London F 3.02SW.2001/177 26/07/2001 Gwynedd M 2.36SW.2001/201 31/08/2001 Vale of Glamorgan F 2.90SW.2001/241a 17/10/2001 Western Isles - 3.20 (approx)SW.2001/242 18/10/2001 Gwynedd F 2.93SW.2001/261 27/11/2001 Ceredigion M 3.10
The sightings data for the bottlenose dolphin outlined by Evans (1995; p.21) aresupported by the NHM’s strandings data. Table 12, shows the sex and lengthdata for bottlenose dolphins stranded around the UK in 2001. The maximum
The Natural History Museum 24
length given for this species in the eastern North Atlantic is 3.81 metres formales and 3.50 metres for females (Perrin and Reilly, 1984). Neonatal length isgiven as 0.98 to 1.30 metres (Evans, 1995).
Unidentified dolphinsUnidentified dolphins
There were twenty nine unidentified dolphins reported in 2001 (Tables 2 & 3).These reports relate to carcasses that were either too decomposed orinaccessible for examination and retrieval. The majority of these reports relateto carcasses washed up around the south west of England (Map 14), and mayrelate to by-catch episodes.
The harbour porpoise was the most common cetacean species to strand in UKwaters in 2001 (see Tables 2 & 3). Consistently, this species represents around50% of all cetaceans reported annually (Figure 6).
Figure 6. Total numbers of reported UK cetacean strandings etc., 1990 – 2001,Figure 6. Total numbers of reported UK cetacean strandings etc., 1990 – 2001,compared with annual numbers of harbour porpoise.compared with annual numbers of harbour porpoise.
In the year 2001, a total of two hundred and fifty nine harbour porpoise wererecorded. For England and Wales, one hundred and ninety one animals wererecorded, whilst for Scotland, the total was sixty four. Four records were alsoreceived from Northern Ireland (Figure 7).
The UK total for 2001 is the highest yet recorded, and represents an increase ofapproximately 25% on the year 2000. Figure 7, shows the distribution ofharbour porpoise strandings by month for 2001. The annual summer peak instrandings of this species noted by Muir et al (1999), thought to be associatedwith the peak months for parturition, is clearly visible for both Wales andScotland. In 2001 an increase in the number of harbour porpoise recordedalong the north west coast of England from Merseyside to Cumbria was alsoseen. This rise was due in part to the improved reporting procedures establishedbetween the NHM and Solway Shark Watch group (Cumbria) in June 2001.
Figure 7. Strandings of harbour porpoise by month for 2001Figure 7. Strandings of harbour porpoise by month for 2001
0
5
10
15
20
25
Jan Feb Mar Apr May Jun Jul Aug Sep O c t Nov Dec
Cornwall Devon Rest of England Wales Scotland N. Ireland
Figure 8, shows the number of harbour porpoise stranded by month form 1997to 2001. A clear correlation can be seen in the data shown in Figures 7 and 8.
Figure 8. Cumulative monthly totals of harbour porpoise stranded, 1997-2001Figure 8. Cumulative monthly totals of harbour porpoise stranded, 1997-2001
0
2 0
4 0
6 0
8 0
1 0 0
1 2 0
1 4 0
1 6 0
Jan Feb Mar A p r May Jun Jul Aug Sep O c t Nov Dec
month
coun
t
The Natural History Museum 26
Figure 9, shows the range of lengths recorded by month for the harbourporpoise from 1997 to 2001:
Figure 8. Harbour porpoise lengths by month, 1997-2001Figure 8. Harbour porpoise lengths by month, 1997-2001
0
0.5
1
1.5
2
2.5
0 1 2 3 4 5 6 7 8 9 10 11 12 13
month
leng
th in
met
res
Female Male Gender unknown
The range of lengths given for adult harbour porpoises are 1.35 to 1.80 metres,and 0.67 to 0.90 metres for newborn animals (Evans, 1995; p.21). Thecumulative length data in Figure 9, show a peak for the number of porpoise inthe range 0.5 to 1.0 metres between June and August. These data can be takento represent an increase in the number of newborn animals, and furtherestablishes the summer months as the peak time for parturition in this species.
Map 15, shows the distribution of harbour porpoise strandings around the UK in2001. The data are similar to that seen in previous years (Map 15a). Map 15b,shows the cumulative distribution of confirmed by-catch, suspected by-catchand animals seen floating at sea for the period 1997 to 2001. The cluster alongthe coast of Humberside and North Yorkshire represents by-caught animalsreported as part of the observer programme operated by the Sea MammalResearch Unit (SMRU).
Six sperm whales were recorded in 2001 (Tables 2 & 3), a figure comparablewith recent years. The distribution of sperm whale strandings around the northand west coasts of Scotland (Map 16) is also similar to previous years. Onerecord was received from the south west of England in February 2001 – a verydecomposed male sperm whale, approximately 12.19 metres in length(SW.2001/32a) found beached at Gorran Haven, Cornwall.
Figure 9. Harbour porpoise length by month, 1997-2001.Figure 9. Harbour porpoise length by month, 1997-2001.
The Natural History Museum 2727
Table 13. Table 13. Physeter catodonPhyseter catodon – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/32a 11/02/2001 Cornwall M 12.19 (approx)SW.2001/124a 17/06/2001 Western Isles - 11.00 (approx)SW.2001/127b 21/06/2001 Western Isles M 16.30SW.2001/181c 29/07/2001 Shetland - -SW.2001/245a 23/10/2001 Shetland M 11.00 (approx)SW.2001/253b 16/11/2001 Shetland - -
Table 13, shows the lengths of sperm whales stranded in 2001. The range oflengths given for adult sperm whales is 8.3 to 11.00 metres for females and 11.0to 15.8 metres for males (Evans, 1995; p.15).
Three records of northern bottlenose whales were received in 2001, all fromScotland (Table 2). This species is not recorded as stranding every year, but thelocations (north and west coast) are not unusual (Map 17). Previous recordsplace most of the strandings around October or November, so the animalrecorded in April 2001 (Table 14 – SW.2001/73b) may be regarded as slightlyunusual.
Table 14. Table 14. Hyperoodon ampullatusHyperoodon ampullatus – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/73b --/04/2001 Orkney - -SW.2001/124a 04/09/2001 Strathclyde F 5.80SW.2001/127b 09/11/2001 Orkney F 7.50 (approx)
The range of lengths given for adult northern bottlenose whales is 6.9 to 8.7metres for females and 7.5 to 9.8 metres for males (Evans, 1995; p.13).
Three records of Sowerby’s beaked whale were received in 2001, all fromScotland (Table 2 & Table 15). This low number is similar to recent years (Table3).
Table 15. Table 15. Mesoplodon bidensMesoplodon bidens – UK strandings, 2001 – UK strandings, 2001SW. numberSW. number Date of strandingDate of stranding County/RegionCounty/Region SexSex Total lengthTotal length
(metres)(metres)SW.2001/81e 14/04/2001 Highland F 4.50SW.2001/156a 15/07/2001 Orkney - 4.00 (approx)SW.2001/210b 18/09/2001 Highland F 4.59
This species is usually recorded along the north and east coasts of Scotland (Map18), but is occasionally stranded along the North Sea coast of England. Therange of lengths given for adult Sowerby’s beaked whales is 5.0 to 5.5 metres(Evans, 1995; p.13).
The Natural History Museum 2828
Unidentified toothed whales and other cetaceansUnidentified toothed whales and other cetaceans
In 2001, there were four strandings of unidentified toothed whales, and twentytwo that were not identified as toothed or baleen whales (see Maps 19 and 20).It is often not possible to identify such carcasses owing either to theirinaccessibility or to their advanced state of decomposition.
The Natural History Museum 2929
Part BPart B
UK Marine Mammal and Marine Turtle PostmortemUK Marine Mammal and Marine Turtle PostmortemInvestigations 2001Investigations 2001
Postmortem investigations of Scottish strandings have been co-ordinated by the SAC Inverness (SAC)since 1992, and in England and Wales by the Institute of Zoology (IoZ) since 1990. Tissue samplesforming the UK national marine mammal tissue archive are jointly held in Scotland at the SAC and inEngland at IoZ. Data from postmortem investigations of marine mammals stranded in the UK are heldjointly at IoZ and SAC.
During 2001, 202 carcasses were examined at postmortem in the UK comprising 189 cetaceans, 11pinnipeds and two marine turtles (Table A). Of these, 80 carcasses were examined in Scotland (Table B)and 122 were examined in England and Wales (Table C). These figures are slightly higher than thenumber of postmortem investigations conducted in the UK in previous years and is consistent with thehigh overall number of UK-stranded cetaceans reported in 2001.
Table A: Table A: UK Marine Mammal and Turtle Postmortem Investigations during 2001UK Marine Mammal and Turtle Postmortem Investigations during 2001
As in previous years, the harbour porpoise was the most commonly stranded cetacean species and wassubjected to more postmortem examinations than other species.
The Natural History Museum 3030
Table B: Table B: Postmortem Investigations conducted in Scotland during 2001Postmortem Investigations conducted in Scotland during 2001
Table C: Table C: Postmortem Investigations conducted in England and Wales during 2001Postmortem Investigations conducted in England and Wales during 2001
Of the 69 harbour porpoises examined at postmortem in England and Wales in 2001, fivewere by-catches retrieved from fishing vessels as part of observer-based research intocetacean by-catch co-ordinated by the Sea Mammal Research Unit. The number ofpostmortem examinations for each species are comparable with those conducted inprevious years in England and Wales, although the numbers of harbour porpoise andcommon dolphin postmortem examinations are slightly higher than in previous years.
The Natural History Museum 3131
Results of UK marine mammal and turtle postmortemResults of UK marine mammal and turtle postmortemexaminations in 2001examinations in 2001
Table D summarises the causes of death of 189 cetaceans, 11 pinnipeds and two marineturtles examined at postmortem in the UK in 2001. These cause of death data are sub-divided into individuals that stranded in Scotland (Table E) and England and Wales (TableF) to enable comparison with data reported for these regions in previous years. It was notpossible to establish the cause of death for 10 harbour porpoises, 4 common dolphins, astriped dolphin and a pilot whale.
Causes of cetacean mortalityCauses of cetacean mortality
Entanglement in fishing gear (By-catch)Of the 16 harbour porpoise by-catches examined in the UK in 2001, 5 were carcassesretrieved directly from fishing vessels as part of observer-based research co-ordinated bythe Sea Mammal Research Unit. Only one by-caught harbour porpoise was recorded inScotland during 2001, which is consistent with the low number of by-catches of anycetacean species recorded in Scotland in previous years. Ten harbour porpoises thatstranded in England and Wales were diagnosed as by-catches. All 10 were juveniles andsix of these stranded in Cornwall or Devon. This is the lowest proportion of strandedharbour porpoise by-catches identified in England and Wales since 1991 and continuesa declining trend in stranded harbour porpoise by-catches in England and Wales sincethe peak in the mid-1990’s (fig. 1).
Between 1990 and 2001, 137 harbour porpoises stranded in England and Wales havebeen diagnosed as having died due to by-catch and the external lesions in many of thesecarcasses were consistent with entanglement in wide-mesh monofilament-type gillnets.The age structure of these 137 by-catches shows a clear bias towards juveniles (fig. 2) andmay indicate a degree of learning is involved in avoidance of gillnets.
Fig. 1: Temporal trends in annual percentage of porpoises diagnosed as by-catch in Eng. & Wales
Twenty common dolphins were diagnosed as having died due to by-catch in 2001, and allstranded in Cornwall, Devon or Dorset between January-April (n=19) or in November(n=1). This seasonal (winter) pattern of stranded common dolphin by-catches in the southwest of England is highly consistent with findings in previous years. The external lesionsassociated with by-catch in common dolphins generally differ from those found in by-caught harbour porpoises, with common dolphins typically having lesions more consistentwith smaller-meshed gear such as trawl netting. These differences in external lesionsprobably reflect the different types of fisheries thought to be predominantly implicated inthe by-catch of these two cetacean species. Interestingly, the age structure of strandedcommon dolphin by-catches in SW England between 1990-2001 appears to be biasedtowards adults rather than juveniles (data not shown) and is in clear contrast to the agestructure of harbour porpoise by-catches stranded in England and Wales during the sameperiod.
Three striped dolphins and a minke whale were also diagnosed to have died due to by-catch in 2001.
Physical trauma (including fatal attack from bottlenose dolphins)Thirty-eight UK-stranded harbour porpoises died due to physical trauma (excluding by-catch) during 2001. Within this group, 28 had lesions consistent with fatal attack frombottlenose dolphins (Figure 3) comprising 19 individuals stranded in Scotland, seven inCardigan Bay, Wales and two in England (Cornwall and Dorset respectively). Fatalattack from bottlenose dolphins is therefore the most common cause of death in UK-stranded harbour porpoises in 2001, as was the case in the proceeding year. The vastmajority of the 2001 cases were juvenile which is consistent with findings in previousyears. Interestingly, the two English cases provide the first evidence of porpoises beingkilled by bottlenose dolphins outside the East Coast of Scotland and Cardigan Bay,Wales.
Fig 2: Age class of 137 by-caught porpoises stranded in England and Wales 1990-2001
0
20
40
60
80
100
neonate juvenile adult
No.
The Natural History Museum 3333
Figure 3: Teeth marks from bottlenose dolphin(s) onFigure 3: Teeth marks from bottlenose dolphin(s) on the skin of a stranded harbour porpoise the skin of a stranded harbour porpoise
Fig 4: Temporal trends in annual % of porpoises killed by T. truncatus in Scotland 1991-2001
Figure 4 and figure 5 show the temporal trends in the percentage of stranded harbourporpoises killed by bottlenose dolphins in Scotland, and England and Wales, respectivelysince 1991. While fatal attack from bottlenose dolphins has been consistently the mostcommon cause of death in Scotland throughout the 1990’s, it is only during the recent1999-2001 period that the number of fatal bottlenose dolphin-harbour porpoiseinteractions have increased significantly in England and Wales (predominantly within theCardigan Bay area). The spatial distribution of stranded harbour porpoises killed bybottlenose dolphins in England and Wales between 1991-2001 is shown in figure 6.
Fig 6:Fig 6: Spatial distribution of 28 stranded harbour porpoises killed by bottlenoseSpatial distribution of 28 stranded harbour porpoises killed by bottlenosedolphins in England and Wales (1991-2001)dolphins in England and Wales (1991-2001)
One harbour porpoise that stranded in Scotland had fatal injuries consistent with aboat’s propeller. Acute physical trauma (of unidentified origin) was attributed as thecause of death of nine harbour porpoises and a common dolphin.
Infectious disease mortalityInfectious disease mortalityDuring 2001, 35 harbour porpoises, two striped dolphins, a common dolphin and awhite-beaked dolphin died due to infectious diseases. Parasitic infections of the lungsresulting in either severe airway obstruction, acute pulmonary haemorrhage, parasiticpneumonia or secondary bacterial or fungal infections caused the death of 27 of theharbour porpoises. Generalised bacterial infections with Streptococcus sp., E. coli,Listonella (Vibrio) damsela and Erysipelothrix rhusiopathiae respectively accounted forthe death of another four harbour porpoises in England and Wales. Two other harbourporpoises that had very heavy lungworm infestations also had some evidence ofterminal septicaemia associated with combined Klebsiella sp./Salmonella sp. andSalmonella sp. infections respectively.
The Natural History Museum 3535
These findings are similar to those identified in UK-stranded harbour porpoises inprevious years. There were no cases of distemper due to morbillivirus infection in anystranded marine mammal carcass in 2001 and no such cases have been identified since1990.
In Scotland, a harbour porpoise had a necrotic gastritis of the pyloric stomach that hadcaused a partial pyloric stenosis, so ingesta would not pass into the intestines. There wasalso a pancreatitis that was causing 'auto-digestion' of the tissues. The primary cause ofthe damage was from fluke blockage of the common bile duct. Another adult femaleporpoise that died in very poor condition had unusual pathology consisting ofpulmonary collapse with terminal circulatory failure. A lungworm reinfection syndromewas thought to be the initiating factor.
A juvenile striped dolphin that had live-stranded was found to have a severemeningoencephalitis. The neuropathology was consistent with previous Brucella sp.meningoencephalitis cases in juvenile striped dolphins, but Brucella was not isolatedfrom the brain. This condition has not been seen in any other species of cetacean andhas not been reported in striped dolphins elsewhere. Another young striped dolphin alsohad a severe bacterial meningoencephalitis that was distinct from the Brucella sp. cases.
Between September 1990 and December 2001, 101 harbour porpoises stranded inEngland and Wales have been diagnosed with fatal infectious disease. These were mainlycaused by lung parasites resulting in pulmonary airway obstruction, pneumonias (oftenwith secondary bacterial or fungal infections) and pulmonary arterial disease, and also bygeneralised bacterial infections. Figure 7 shows that within these 101 animals asignificantly higher proportion (25%) of all porpoises examined in the winter (October-March) died of infectious disease than in the summer (April-September) where infectiousdisease mortality accounted for only 15% of porpoises examined.
StarvationStarvationStarvation was attributed as the cause of death in animals that were severely emaciated inthe absence of any other underlying disease processes that could explain the poor
Fig 7: Seasonal effects on percentage of harbour porpoises in England and Wales diagnosed with
infectious disease mortality 1990-2001
05
10
1520
2530
Winter Summer
%
The Natural History Museum 3636
nutritional status. The cause of death of nine harbour porpoises (including 6 neonates),two common dolphins, two white-beaked dolphins, a Risso’s dolphin, a minke whale, ahumpback whale and a killer whale (with chronic tooth abscesses) was attributed tostarvation. Both white-beaked dolphins were juveniles and probably still maternallydependent.
Live strandingLive strandingLive stranding was the most common cause of death in cetacean species other thatharbour porpoises and common dolphins examined during 2001. Live stranding wasattributed as the cause of death in animals that were known or suspected (frompostmortem examination) to have live stranded and that were in good health andnutritional status. The cause of death of diseased or emaciated animals that live strandedwas attributed to the disease process rather than the live stranding event. Live strandingwas attributed as the cause of death of six harbour porpoises, five common dolphins, fourAtlantic white-sided dolphins, three bottlenose dolphins, two striped dolphins, two pilotwhales, two Sowerby’s beaked whales, a white beaked dolphin, a Risso’s dolphin and anorthern bottlenose whale.
One of the three live stranded bottlenose dolphins stranded in the River Thames andwas probably very aged and beginning to lose condition. The second was an adultbottlenose dolphin with unusual heart pathology involving focal myocardial fattychange. In other animals this is seen in acute systemic disease, especially toxaemia, andin anaemia. There was no evidence of these conditions in this case. However there wasno convincing evidence of myocardial insufficiency so the change may not have been ofsignificance.
TumoursTumoursNo tumours were recorded in marine mammals stranded in England and Wales in 2001.In Scotland, however, an adult female porpoise had severe large fibroleiomyomata(benign tumours of smooth muscle and fibrous tissue) in the wall of the uterus. Theyhad prevented the porpoise from giving birth and the death was due to toxaemia fromthe mascerated foetus still present in the uterus. Another adult Scottish porpoise hadseveral small fibroleiomyomata in the uterus which appeared to be incidental findings.These tumours are the most common tumour of the female reproductive tract of catsand dogs, but are very uncommon in terrestrial ruminants.
Novel liver diseaseNovel liver diseaseA juvenile Risso's dolphin that had died in very poor condition was found to have amassively enlarged liver. Almost all the liver tissue had been replaced by variable-sized gas-filled lesions measuring up to a few centimetres in diameter. These were chronic lesionsand there was intervening fibrous tissue. This pathology appears unique to cetaceans andis being investigated further prior to publication.
Other causes of deathOther causes of deathThe other remaining causes of death of stranded cetaceans examined in 2001 are detailedin Tables D, E and F and Appendix 3.
The Natural History Museum 3737
Causes of seal mortality
Two grey seals died of by-catch, one of acute physical trauma, one of starvation andone was euthanased in a rehabilitation centre. Four harbour seals died of starvation, oneof by-catch and one of heavy lungworm infestation.
Causes of mortality in marine turtles
A leatherback turtle died due to by-catch in a creel rope off the Cornish coast. Aloggerhead turtle that stranded in Scotland died due to starvation/hypothermia.
The Natural History Museum 3838
Table D: Causes of death of marine mammals and turtles stranded in theTable D: Causes of death of marine mammals and turtles stranded in theUK in 2001UK in 2001
SpeciesSpecies Cause of deathCause of death No.No.
*Of the 16 harbour porpoise by-catches reported here, 5 were carcasses retrieveddirectly from fishing vessels as part of observer-based research conducted by the SeaMammal Research Unit. The postmortem investigations of these carcasses wereconducted in collaboration with the Sea Mammal Research Unit.
The Natural History Museum 4040
Table E: Causes of death of marine mammals and turtles stranded inTable E: Causes of death of marine mammals and turtles stranded inScotland in 2001Scotland in 2001
Table F: Causes of death of marine mammals and turtles stranded inTable F: Causes of death of marine mammals and turtles stranded inEngland and Wales in 2001England and Wales in 2001
SpeciesSpecies Cause of deathCause of death No No.
Halichoerus grypus By-catch 2Euthanased in rehabilitation centre 1Physical trauma, unidentified 1
Phoca vitulina By-catch 1
Dermochelys coriacea By-catch 1
*Of the 15 harbour porpoise by-catches reported here, 5 were carcasses retrieved directly fromfishing vessels as part of observer-based research conducted by the Sea Mammal ResearchUnit. The postmortem investigations of these carcasses were conducted in collaboration withthe Sea Mammal Research Unit.
BrucellaBrucellaThere were six non-fatal isolations of Brucella sp. from marine mammals in Scotland andnone from England and Wales during 2001. Two harbour porpoises and a common sealinfected with Brucella sp. had no associated pathology. In an adult Atlantic white-sideddolphin that had live-stranded there were multiple foci of splenic necrosis from whichBrucella sp. was recovered. A porpoise, where the primary problem was heavy lungparasitism, had a large sub-blubber Brucella abscess. Another porpoise, where the causeof death could not be established due to autolysis, had a severe abscessing Brucellaepididymitis.
SalmonellaSalmonellaSalmonella enterica serovar Typhimurium DT195 was isolated from a common seal in arehabilitation centre. The host-adapted monophasic group B salmonella frequentlyfound in harbour porpoises but seldom associated with disease was recovered fromeight Scottish-stranded animals and 14 animals that stranded in England and Walesduring the year. Although these isolates were rarely associated with disease, two of theinfected porpoises from England and Wales had generalised Salmonella sp. infectionsand a third infected porpoise had a severe, chronic and possibly bacterial pneumonia.
CampylobacterCampylobacterCampylobacter sp. was recovered from the intestine of a Risso’s dolphin in Scotland.
Staphylococcus delphiniStaphylococcus delphiniThis coagulase positive species initially reported from purulent skin conditions of twocaptive dolphins (Varaldo et al. 1988) was recovered from a grey seal in rehabilitation inCornwall. The only previous finding of this organism from a sea mammal in the UK wasfrom the nose of a common seal.
Streptococcus phocaeStreptococcus phocaeThis pyogenic species was recovered from a common seal and a porpoise in Scotland.
The Natural History Museum 4444
VibriosVibrios In Scotland, Photobacterium damsela was recovered from eight animals all between themonths of April and September, demonstrating a similar seasonal pattern to previousyears for this organism. Vibrio alginolyticus was recovered from three porpoises. InEngland and Wales a range of Vibrio spp. were isolated from seven harbour porpoises,two common dolphins and a pilot whale.
PasteurellaceaePasteurellaceaeIn Scotland, Actinobacillus delphinicola continued to be the most commonly isolatedmember of the Pasteurellaceae and was recovered from four harbour porpoises, anAtlantic white-sided dolphin and a bottlenose dolphin. In three of the porpoisesmonophasic group B salmonella was also recovered, a pattern apparent in previousyears suggesting a possible link between these organisms in porpoises. Haemophilusspp. were recovered on two occasions from a Risso’s dolphin and a harbour porpoiserespectively. As yet unidentified Pasteurellaceae were recovered from three cetaceans, aSowerby’s beaked whale, a northern bottlenose whale and a harbour porpoise.
Arcanobacterium pluranimaliumArcanobacterium pluranimaliumA paper describing A. pluranimalium was published in 2001. It had first been recoveredfrom a porpoise in 1994 and later in a deer from Sweden. It has not been isolated sincefrom a sea mammal, but during this year it has been the subject of interest in thelivestock sector due to its involvement with ovine abortion and other infections(Foster, G., Ritchie, C., Cowie, R.A., Rusbridge, S.M., Collins, M.D. and Hoyles, L.(2001) Arcanobacterium/Corynebacterium-like bacterial isolates from sheep. VeterinaryRecord 148: 284) and has also been found in a case of bovine mastitis (publicationpending).
Investigations of relationships between environmental contaminants andInvestigations of relationships between environmental contaminants andhealth status and reproductive functionhealth status and reproductive function
Tissue samples for toxicological analyses were collected and archived from all strandedmarine mammals examined during 2001. A number of samples taken from UK-strandedcetaceans were sent to the CEFAS Burnham Laboratory, Essex for toxicological analysesduring 2001.
Investigation of the association between chronic PCB exposure and thymic involution andcystic transformation in harbour porpoisesDuring 2001 a study of the relationship between chronic PCB exposure and thymicinvolution and thymic pathology in stranded harbour porpoises was continued at theInstitute of Zoology. Thymuses of approximately 100 harbour porpoises stranded inEngland and Wales have been examined for quantitative indices of thymic involutionand cystic transformation histologically. These indices will be compared statistically tolevels of 25 individual PCB congeners in blubber tissue. Factors such as age, sex, andcause of death (health status) will also be included in the analyses. The study is an
The Natural History Museum 4545
extension of a research project conducted by Catherine Goldsworthy (MRCVS) as partof a Masters degree in Wild Animal Health in 2000.
Investigations of relationships between endocrine disrupting chemicals and testiculardevelopment in harbour porpoisesDuring 2001 samples of testes from UK-stranded harbour porpoises continued to beanalysed for stages of testicular development at the Institute of Zoology usingimmunohistochemical techniques. The main aim of the research is to produce qualitativeand quantitative indices of testicular development and fertility in harbour porpoises andto test for correlations between these parameters and exposure to persistentenvironmental pollutants such as PCBs. The analyses form part of a research programme(funded by World Wide Fund for Nature-UK) investigating potential relationshipsbetween endocrine disrupting chemicals and fertility using tissues generated through theUK Marine Mammal Strandings Project.
New Research Activity (harbour porpoise genetics)New Research Activity (harbour porpoise genetics)
In 2001 Oliver Thatcher was appointed to begin a NERC-funded PhD studentshipinvestigating the population structure of harbour porpoises in UK-waters using genetic(microsatellite) markers. It is hoped that the research will lead to a morerobustunderstanding of the population structure of porpoises in UK and Europeanwaters, and should help to define management units for conservation purposes. Theresearch will also investigate host genetic factors in resistance to parasitic and otherdiseases using novel molecular techniques. The research will be conducted jointly at theInstitute of Zoology and Cambridge University under the supervision of Dr. SimonGoodman (IoZ), Dr. Bill Amos (Cambridge Uni.) and Paul Jepson (IoZ).
The Natural History Museum 4646
2001 Publications2001 Publications
Bennett, P.M., Jepson, P.D., Law, R.J., Jones, B.R., Kuiken, T., Baker, J.R., Rogan, E. &Kirkwood, J.K. (2001) Exposure to heavy metals and infectious disease mortality in harbourporpoises from England and Wales. Environmental Pollution, 112, 33-40
Cloeckaert, A., Verger, J-M., Grayon, M., Paquet, J-Y., Garin-Bastuji, B. Foster, G., andGodfroid, J. (2001) Classification of Brucella spp. isolated from marine mammals by DNApolymorphism at the omp2 locus. Microbes and Infection 3:729-738.
Deaville, R., Bennett, P.M., Jepson, P.D., Penrose, R. (2001) Fatal interaction betweenharbour porpoises and bottlenose dolphins in Cardigan Bay, Wales – is prey competition toblame? Proceedings of the fifthteenth annual conference of the European Cetacean Society,Rome, Italy, 7-9 May 2001.
Hoyles, L., Pascual, C., Falsen, E., Foster, G., Grainger, J. M. and Collins, M. D. (2001)Actinomyces marimammalium sp. nov., from marine mammals. International Journal ofSystematic and Evolutionary Microbiology 51:151-156.
Hoyles, L., Foster, G., Falsen, E., Thomson, L. F. and Collins, M. D. (2001) Facklamiamiroungaei sp. nov., from a juvenile southern elephant seal (Mirounga leonina). InternationalJournal of Systematic and Evolutionary Microbiology 51:1401-1403.
Jepson, P.D., Bennett, P.M., Deaville, R., Northridge, S. (2001) Pathology of harbour porpoise(Phocoena phocoena) by-catches retrieved from UK gillnet fisheries. Proceedings of thefifthteenth annual conference of the European Cetacean Society, Rome, Italy, 7-9 May 2001.
Lawson, P. A., Falsen, E., Foster, G., Eriksson, E., Weiss, N. and Collins, M. D. (2001)Arcanobacterium pluranimalium sp. nov. isolated from porpoise and deer. International Journalof Systematic and Evolutionary Microbiology 51:55-59.
Santos, M.B., Pierce, G.J., Reid, R.J., Patterson, I.A.P., Ross, H.M., Mente, E., (2001) Stomachcontents of bottlenose dolphins (Tursiops truncatus) in Scottish waters, J. Mar. Biol. Ass. UK,81, 873-878
Santos, M.B., Pierce, G.J., Reid, R.J.,., Ross, H.M., Patterson, I.A.P. Variability in the diet ofharbour porpoises (Phocoena phocoena ) in Scottish Waters. Ecological Monographs, In Press
Van Bressem, M.F., Van Waerebeek, K., Jepson, P.D., Raga, J.A., Duignan, P.J., Nielsen, O., DiBeneditto, A.P., Siciliano, S., Ramos, R., Kant, W., Peddermors, V., Kinoshita, R., Ross, P.S.,López-Fernandez, Evans, K., Crespo, E. & Barrett, T. (2001) An insight into dolphin morbillivirusworldwide. Veterinary Microbiology 8181: 287-304
Wilson, B., Hammond, P.S., Reid, R.J., Grellier, K. and Thompson, P.M. Range expansion inNorth Sea bottlenose dolphins: evidence and management implications. Submitted to Journalof Applied Ecology
The Natural History Museum 4747
ReferencesReferences
Christensen, I. (1980) Catch and effort in the Norwegian minke whale fishery in the1978 whaling season. Report of the International Whaling Commission 3030 : 209-212.
Dahlheim, M.E. and Heyning, J.E. (1999) Killer Whale. In: The Handbook of MarineMammals Vol.6 – the Second Book of Dolphins and the Porpoises. S. Ridgway and R.Harrison (eds). Academic Press, London.
Evans, W.E. (1994) Common Dolphin. In: The Handbook of Marine Mammals Vol.5 –the First Book of Dolphins. S. Ridgway and R. Harrison (eds). Academic Press,London.
Evans, P.G.H. (1995) Guide to the Identification of Whales, Dolphins and Porpoises inEuropean Seas. Sea Watch Foundation Publication, Oxford, 1995.
Fraser, F.C. (1969) Guide for the Identification and Reporting of Stranded Whales,Dolphins and Porpoises on the British Coasts. The British Museum (Natural History),London.
Gambell, R. (1985) Sei Whale. In: The Handbook of Marine Mammals Vol.3 – theSirenians and Baleen Whales. S. Ridgway and R. Harrison (eds). Academic Press,London.
Kuiken, T., Simpson, V.R., Allchin, C.R., Bennett, P.M., Codd, G.A., Harris, E.A.,Howes, G.J., Kennedy, S., Kirkwood, J.K., Law, R.J., Merrett, N.R. and Phillips, S.(1994). Mass mortality of common dolphins (Delphinus delphis) in south west Englanddue to incidental capture in fishing gear. Veterinary Record 134134 : 81-89.
Muir, A.I., Chimonides, P.D.J. & Spurrier, C.J.H. (1999) Trends in Cetacean Strandings onthe British Coastline, 1998. The Natural History Museum, London.
Perrin, W.F. & Reilly, S.B. (1984) Reproductive parameters of dolphins and smallwhales of the family Delphinidae. In: Reproduction in Whales, Dolphins and Porpoises(Eds W.F. Perrin, R.L. Brownwell and D.P. DeMaster) pp.97-133. Rep. Int. Whal.Comm, Spec. Issue No. 6, Cambridge.
Winn, H.E. & Reichley, N.E. (1985) Humpback Whale. In: The Handbook of MarineMammals Vol.3 – the Sirenians and Baleen Whales. S. Ridgway and R. Harrison (eds).Academic Press, London.
The Natural History Museum 48
Map 1. All cetacean strandings records, 2001Map 1. All cetacean strandings records, 2001
Appendix 3: UK-stranded marine mammal and marine turtles examined at post-mortem during 2001Appendix 3: UK-stranded marine mammal and marine turtles examined at post-mortem during 2001
NHM ref.NHM ref. PM no.PM no. SpeciesSpecies SexSex LengthLength Date foundDate found CountyCounty CauseCause of Death of Death
SW2001/1 M6/1/01 Delphinus delphis F 200 02/01/01 Cornwall physical trauma, by-catchSW2001/2 M10/1/01 Delphinus delphis M 228 03/01/01 Cornwall physical trauma, by-catchSW2001/3 M11/1/01 Delphinus delphis M 202 03/01/01 Cornwall not establishedSW2001/4 XT014/01 Phocoena phocoena M 122 03/01/01 Devon physical traumaSW2001/5 XT029/01 Delphinus delphis F 119 04/01/01 Devon live strandingSW2001/5B M001/01 Phocoena phocoena M 102 05/01/01 Shetland starvation/hypothermiaSW2001/7 XT041/01 Delphinus delphis F 133 07/01/01 Devon physical trauma, by-catchSW2001/10 XT049/01 Phocoena phocoena F 131 10/01/01 Devon physical trauma, by-catchSW2001/11 XT047/01 Phocoena phocoena F 157 10/01/01 Devon physical trauma, by-catchSW2001/12 S2031 Delphinus delphis F 208 14/01/01 Gwynedd cerebral infarctSW2001/15 M67/1/01 Phocoena phocoena F 129 19/01/01 Cornwall physical traumaSW2001/15B M004/01 Phocoena phocoena F 148 18/01/01 Tayside physical trauma (bottlenose dolphin attack)SW2001/16A M005/01 Phocoena phocoena M 144 22/01/01 Shetland haemorrhage, pulmonary (parasitic)SW2001/17 M84/1/01 Phocoena phocoena F 151 23/01/01 Cornwall physical trauma, by-catchSW2001/18 M87/1/01 Cetacean (species indet.) F 205 24/01/01 Cornwall not establishedSW2001/19 M88/1/01 Phocoena phocoena F 130 24/01/01 Cornwall physical trauma, by-catchSW2001/20 M93/1/01 Phocoena phocoena M 133 25/01/01 Cornwall physical traumaSW2001/21 XT076/01 Phocoena phocoena F 171 24/01/01 Devon haemorrhage, pulmonary (parasitic)SW2001/21A M006/01 Phocoena phocoena F 117 24/01/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/21B M008/01 Phocoena phocoena F 129 25/01/01 Strathclyde parasitism, pulmonary (heavy)SW2001/23 XT096/01 Phocoena phocoena M 152 26/01/01 Essex pneumonia, parasiticSW2001/24A XT097/01 Phocoena phocoena M 130 27/01/01 Devon parasitism (heavy)SW2001/25 XT077/01 Delphinus delphis M 218 28/01/01 Devon physical trauma, by-catchSW2001/25C M010/01 Phocoena phocoena F 125 28/01/01 Fife physical trauma (bottlenose dolphin attack)SW2001/29(1) XT106/01 Stenella coeruleoalba U 140 07/02/01 Somerset physical trauma, by-catchSW2001/29(2) XT105/01 Stenella coeruleoalba U 140 07/02/01 Somerset physical trauma, by-catchSW2001/29(3) XT104/01 Stenella coeruleoalba M 145 07/02/01 Somerset physical trauma, by-catchSW2001/30 XT103/01 Phocoena phocoena F 129 07/02/01 Devon physical trauma, by-catchSW2001/33A EXTERNAL Phocoena phocoena F 123 12/02/01 Dorset physical trauma, by-catchSW2001/34 EXTERNAL Delphinus delphis M 210 13/02/01 Dorset physical trauma, by-catchSW2001/35C M015/01 Grampus griseus F 261 14/02/01 Orkney hepatopathySW2001/36 XT110/01 Phocoena phocoena F 114 17/02/01 Kent otitis media, mycoticSW2001/38C M022/01 Phocoena phocoena M 130 25/02/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/40 XT1008/01 Phocoena phocoena F 105 07/03/01 Swansea physical trauma
The Natural History Museum 80
NHM ref.NHM ref. PM no.PM no. SpeciesSpecies SexSex LengthLength Date foundDate found CountyCounty Cause of DeathCause of Death
SW2001/40A M024/01 Phocoena phocoena M 137 07/03/01 Western Isles physical trauma, by-catch?SW2001/41 XT221/01 Delphinus delphis M 144 08/03/01 Cornwall starvationSW2001/43A M025/01 Phocoena phocoena F 114 08/03/01 Tayside physical trauma (bottlenose dolphin attack)SW2001/44 XT205/01 Delphinus delphis M 210 09/03/01 Devon physical trauma, by-catchSW2001/45 XT206/01 Delphinus delphis F 191 11/03/01 Devon physical trauma, by-catchSW2001/47 XT216/01 Phocoena phocoena F 168 12/03/01 Devon physical trauma (bycatch and BND kill type lesions)SW2001/48 XT207/01 Delphinus delphis F 208 12/03/01 Devon physical trauma, by-catchSW2001/50A EXTERNAL Delphinus delphis M 209 12/03/01 Cornwall physical trauma, by-catchSW2001/51 EXTERNAL Delphinus delphis M 195 13/03/01 Devon physical trauma, by-catchSW2001/52 EXTERNAL Delphinus delphis M 211 15/03/01 Devon physical trauma, by-catchSW2001/53 EXTERNAL Delphinus delphis M 198 13/03/01 Cornwall physical trauma, by-catchSW2001/54 EXTERNAL Delphinus delphis M 189 14/03/01 Devon physical trauma, by-catchSW2001/55 EXTERNAL Delphinus delphis M 135 14/03/01 Devon physical trauma, by-catchSW2001/55A M027/01 Phocoena phocoena F 126 14/03/01 Western Isles parasitism, pulmonary and abscessationSW2001/56 EXTERNAL Delphinus delphis F 187 14/03/01 Devon physical trauma, by-catchSW2001/57 XT222/01 Delphinus delphis M 209 18/03/01 Devon physical trauma, by-catchSW2001/59D M030/01 Phocoena phocoena F 155 20/03/01 Strathclyde parasitism, pulmonary (heavy)SW2001/60 EXTERNAL Megaptera novaeangliae M 1066 21/03/01 Kent starvationSW2001/62 XT233/01 Phocoena phocoena F 122 21/03/01 Pembrokeshire live strandingSW2001/66 XT241/01 Delphinus delphis F 212 26/03/01 Cornwall physical trauma, by-catchSW2001/67 XT244/01 Delphinus delphis M 222 26/03/01 Cornwall physical trauma, by-catchSW2001/73A M031/01 Phocoena phocoena M 112 30/03/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/75A M032/01 Tursiops truncatus M 314 02/04/01 Highland live strandingSW2001/77 XT265/01 Delphinus delphis M 205 04/04/01 Devon physical trauma, by-catchSW2001/79A M034/01 Phocoena phocoena M 109 08/04/01 Highland physical trauma (bottlenose dolphin attack)SW2001/79B M035/01 Phocoena phocoena F 163 09/04/01 Strathclyde not establishedSW2001/79C M038/01 Phocoena phocoena M 124 09/04/01 Tayside physical trauma (bottlenose dolphin attack)SW2001/79D M036/01 Phocoena phocoena F 104 10/04/01 Highland parasitism, pulmonary (heavy)SW2001/80A M039/01 Phocoena phocoena F 115 11/04/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/81D M040/01 Phocoena phocoena M 107 14/04/01 Highland gastritis, parasiticSW2001/81E M041/01 Mesoplodon bidens F 450 14/04/01 Highland live strandingSW2001/81F M042/01 Balaenoptera acutorostrata F 490 14/04/01 Fife starvationSW2001/83A M043/01 Phocoena phocoena M 118 17/04/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/83B M044/01 Globicephala melas F 308 17/04/01 Grampian live strandingSW2001/83C M045/01 Phocoena phocoena F 121 19/04/01 Grampian parasitism, generalised (heavy)SW2001/83D M046/01 Phocoena phocoena M 153 20/04/01 Highland parasitism, pulmonary (heavy)
The Natural History Museum 81
NHM ref.NHM ref. PM no.PM no. SpeciesSpecies SexSex LengthLength Date foundDate found CountyCounty Cause of DeathCause of Death
SW2001/85 XT316/01 Phocoena phocoena F 122 21/04/01 Ceredigion physical trauma (bottlenose dolphin attack)SW2001/85B M047/01 Phocoena phocoena M 114 21/04/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/85C M048/01 Phocoena phocoena M 104 21/04/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/85D M049/01 Phocoena phocoena M 110 24/04/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/87A M051/01 Phocoena phocoena M 129 26/04/01 Strathclyde parasitism, pulmonary (heavy)SW2001/87B M052/01 Lagenorhynchus acutus M 252 26/04/01 Highland live strandingSW2001/88 XT358/01 Phocoena phocoena F 112 27/04/01 Norfolk parasitism, pulmonary and cardiac (heavy)SW2001/89 S2032 Phocoena phocoena F 111 28/04/01 Merseyside pneumonia, parasitic and bacterialSW2001/92 XT357/01 Phocoena phocoena F 117 30/04/01 Essex generalised bacterial infectionSW2001/93 XT411/01 Stenella coeruleoalba M 173 02/05/01 Devon starvation (acute pancreatitis)SW2001/94 XT413/01 Phocoena phocoena M 119 01/05/01 Ceredigion physical trauma (bottlenose dolphin attack)SW2001/97A M055/01 Phocoena phocoena M 103 04/05/01 Highland starvation/hypothermiaSW2001/102A M058/01 Phocoena phocoena M 110 09/05/01 Highland physical trauma (bottlenose dolphin attack)SW2001/102B M057/01 Phocoena phocoena M 151 10/05/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/107A M063/01 Phocoena phocoena F 110 17/05/01 Highland live strandingSW2001/109B M059/01 Phocoena phocoena F 110 18/05/01 Tayside not establishedSW2001/109C M064/01 Grampus griseus M 210 19/05/01 Western Isles live strandingSW2001/110 XT489/01 Phocoena phocoena F 139 20/05/01 Cornwall parasitism, pulmonary and cardiac (heavy)SW2001/111 XT480/01 Delphinus delphis M 211 21/05/01 Cornwall starvation (old age)SW2001/111A M067/01 Tursiops truncatus F 330 23/05/01 Highland live strandingSW2001/113 M3/6/01 Phocoena phocoena M 140 27/05/01 Cornwall pneumonia, parasiticSW2001/118 S2033 Phocoena phocoena F 75 04/06/01 Anglesey live strandingSW2001/120 EXTERNAL Balaenoptera acutorostrata M 520 10/06/01 Northumberland entanglementSW2001/122 XT995/01 Phocoena phocoena M 71 11/06/01 Ceredigion not establishedSW2001/122B M077/01 Phocoena phocoena F -9 12/06/01 Lothian not establishedSW2001/123 XT996/01 Phocoena phocoena M 82 13/06/01 Carmarthenshire physical traumaSW2001/124B M080/01 Phocoena phocoena F 79 18/06/01 Fife neonatal deathSW2001/127 XT540/01 Phocoena phocoena M 136 21/06/01 Humberside physical trauma, by-catch (known)SW2001/127A M082/01 Phocoena phocoena F 78 21/06/01 Grampian stillbirthSW2001/127C M083/01 Phocoena phocoena F 110 22/06/01 Strathclyde parasitism, pulmonary (heavy)SW2001/128B M084/01 Delphinus delphis M 222 26/06/01 Fife live strandingSW2001/138 XT796/01 Phocoena phocoena M 78 01/07/01 Carmarthenshire starvation/hypothermia (neonate)SW2001/139 XT670/01 Phocoena phocoena M 140 04/07/01 Humberside physical trauma, by-catch (known)SW2001/140C M091/01 Phocoena phocoena M 84 07/07/01 Fife physical trauma (bottlenose dolphin attack)SW2001/141 XT672/01 Tursiops truncatus F 302 08/07/01 Greater London live stranding (senility)SW2001/144 XT704/01 Phocoena phocoena F 82 09/07/01 Humberside physical trauma, by-catch (known)
The Natural History Museum 82
NHM ref.NHM ref. PM no.PM no. SpeciesSpecies SexSex LengthLength Date foundDate found CountyCounty Cause of DeathCause of Death
SW2001/144A M090/01 Phocoena phocoena F 116 09/07/01 Strathclyde parasitism, pulmonary (heavy)SW2001/146(1)M092/01A Lagenorhynchus acutus M 250 10/07/01 Shetland live strandingSW2001/146(2)M092/01B Lagenorhynchus acutus F 224 10/07/01 Shetland live strandingSW2001/149 XT723/01 Phocoena phocoena F 138 12/07/01 Humberside physical trauma, by-catch (known)SW2001/158 XT747/01 Phocoena phocoena F 119 17/07/01 Kent generalised bacterial infectionSW2001/160 XT767/01 Delphinus delphis M 205 17/07/01 Devon starvationSW2001/161 M41/7/01 Phocoena phocoena M 131 18/07/01 Cornwall pneumonia, parasitic and mycoticSW2001/162A M099/01 Lagenorhynchus albirostris F 245 17/07/01 Grampian live strandingSW2001/163A S2034 Phocoena phocoena M 85 19/07/01 Anglesey starvation/hypothermia (neonate)SW2001/163B M100/01 Phocoena phocoena F 164 18/07/01 Strathclyde neoplasia (uterine), dystocia and foetal macerationSW2001/168 XT910/01 Phocoena phocoena F 88 22/07/01 Ceredigion starvation/hypothermia (neonate)SW2001/170 XT908/01 Phocoena phocoena F 73 22/07/01 Carmarthenshire live strandingSW2001/172A M105/01 Phocoena phocoena M 157 23/07/01 Highland live strandingSW2001/174 XT930/01 Phocoena phocoena F 92 25/07/01 Ceredigion live strandingSW2001/181B M111/01 Phocoena phocoena F 164 29/07/01 Dumfries & Galloway parasitism, pulmonary (heavy) and live strandingSW2001/183B M113/01 Phocoena phocoena M 104 03/08/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/186 XT872/01 Phocoena phocoena M 149 06/08/01 Swansea pulmonary parasitism, heavy/gen. bacterial infectionSW2001/187B M117/01 Phocoena phocoena M 139 07/08/01 Strathclyde not establishedSW2001/188 XT877/01 Phocoena phocoena F 98 08/08/01 Norfolk starvation/hypothermiaSW2001/189 XT879/01 Stenella coeruleoalba F 158 15/08/01 Gloucestershire not establishedSW2001/190B M120/01 Phocoena phocoena F 119 17/08/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/191 XT986/01 Phocoena phocoena F 83 18/08/01 Ceredigion physical traumaSW2001/192D M121/01 Phocoena phocoena F 140 19/08/01 Tayside not establishedSW2001/193 XT905/01 Phocoena phocoena M 147 21/08/01 Pembrokeshire generalised bacterial infectionSW2001/193B M123/01 Phocoena phocoena M 147 22/08/01 Tayside not establishedSW2001/195 S2039 Phocoena phocoena F 92 24/08/01 Gwynedd lipaemia/fatty liverSW2001/198 XT907/01 Phocoena phocoena F 82 28/08/01 Ceredigion generalised bacterial infectionSW2001/199 M76/8/01 Phocoena phocoena M 134 28/08/01 Cornwall not establishedSW2001/199B M126/01 Lagenorhynchus acutus M 257 28/08/01 Shetland live strandingSW2001/203 XT912/01 Phocoena phocoena M 113 03/09/01 Ceredigion physical trauma (bottlenose dolphin attack)SW2001/204C M130/01 Hyperoodon ampullatus F 580 04/09/01 Strathclyde live strandingSW2001/205 XT937/01 Phocoena phocoena M 136 07/09/01 Norfolk physical traumaSW2001/205D M131/01 Stenella coeruleoalba F 206 09/09/01 Highland meningo-encephalitisSW2001/205E M133/01 Stenella coeruleoalba F 189 10/09/01 Highland meningo-encephalitis (?Brucella)SW2001/206A S2037 Phocoena phocoena F 79 15/09/01 Anglesey starvation/hypothermia (neonate)SW2001/206C M135/01 Phocoena phocoena F 168 14/09/01 Strathclyde pulmonary collapse
The Natural History Museum 83
NHM ref.NHM ref. PM no.PM no. SpeciesSpecies SexSex LengthLength Date foundDate found CountyCounty Cause of DeathCause of Death
SW2001/206D M136/01 Phocoena phocoena F 137 15/09/01 Grampian physical trauma (bottlenose dolphin attack)SW2001/207 XT981/01 Phocoena phocoena M 113 16/09/01 Ceredigion physical trauma (bottlenose dolphin attack)SW2001/208 S2036 Phocoena phocoena F 120 17/09/01 Merseyside parasitism, pulmonary, pneumonia, gen. bact. inf.SW2001/210 XT980/01 Phocoena phocoena M 110 18/09/01 Ceredigion physical trauma (bottlenose dolphin attack)SW2001/210B M138/01 Mesoplodon bidens M 459 18/09/01 Strathclyde live strandingSW2001/211 S2038 Grampus griseus F 314 20/09/01 Ceredigion starvationSW2001/212 XT993/01 Phocoena phocoena M 94 21/09/01 Suffolk starvation/hypothermia (neonate)SW2001/212A M142/01 Stenella coeruleoalba M 167 22/09/01 Highland live strandingSW2001/212B M141/01 Lagenorhynchus albirostris F 128 22/09/01 Orkney parasitism, pulmonary (heavy)SW2001/216 XT998/01 Phocoena phocoena M 106 27/09/01 Kent physical trauma, by-catchSW2001/217 XT1001/01 Stenella coeruleoalba F 168 27/09/01 Devon pancreatitis (necrotising) & peritonitis (gen. bact. inf.?)SW2001/218 XT999/01 Phocoena phocoena F 144 27/09/01 Humberside physical trauma, by-catch (known)SW2001/221 M6/10/01 Delphinus delphis M 212 01/10/01 Cornwall not establishedSW2001/227 M18/10/01 Globicephala melas F 197 04/10/01 Cornwall not establishedSW2001/228 XT1042/01 Phocoena phocoena M 123 04/10/01 Gwynedd physical trauma (bottlenose dolphin attack)SW2001/229 XT1020/01 Phocoena phocoena F 157 05/10/01 Dorset physical trauma (bottlenose dolphin attack)SW2001/230 XT1048/01 Phocoena phocoena M 146 06/10/01 Carmarthenshire pneumoniaSW2001/231 M31/10/01 Phocoena phocoena F 127 08/10/01 Cornwall pneumonia, parasitic (and bacterial?)SW2001/233 XT1032/01 Phocoena phocoena M 98 09/10/01 Pembrokeshire live strandingSW2001/234 EXTERNAL Orcinus orca M 590 09/10/01 Merseyside starvationSW2001/235C M89/10/01 Delphinus delphis F 188 25/10/01 Cornwall not establishedSW2001/236 S2040 Phocoena phocoena F 98 13/10/01 Gwynedd starvation/hypothermiaSW2001/238 XT1049/01 Globicephala melas F 178 15/10/01 Devon live strandingSW2001/245C M147/01 Phocoena phocoena M 154 01/11/01 Highland not establishedSW2001/248 XT1089/01 Phocoena phocoena F 115 05/11/01 Ceredigion physical trauma (bottlenose dolphin attack)SW2001/251 XT1102/01 Phocoena phocoena F 108 09/11/01 Neath Port Talbot physical trauma, by-catchSW2001/253 XT1103/01 Phocoena phocoena M 110 09/11/01 Ceredigion physical traumaSW2001/259A M161/01 Phocoena phocoena F 149 22/11/01 Strathclyde severe bacterial pneumoniaSW2001/260 XT1131/01 Phocoena phocoena M 130 23/11/01 Kent pneumothorax, pneumonia (parasitic),
thrombovasculitisSW2001/262 XT1145/01 Phocoena phocoena M 98 28/11/01 Gwynedd physical trauma, by-catchSW2001/263 XT1144/01 Delphinus delphis F 203 30/11/01 Devon physical trauma, by-catchSW2001/268 M23/12/01 Delphinus delphis M 217 05/12/01 Cornwall physical traumaSW2001/268B M167/01 Delphinus delphis F 199 04/12/01 Lothian live strandingSW2001/268C M168/01 Lagenorhynchus albirostris M 164 04/12/01 Grampian starvationSW2001/268D M173/01 Delphinus delphis F 211 04/12/01 Fife live stranding
The Natural History Museum 84
NHM ref.NHM ref. PM no.PM no. SpeciesSpecies SexSex LengthLength Date foundDate found CountyCounty Cause of Cause of DeathDeath
SW2001/268E M170/01 Lagenorhynchus albirostris M 172 06/12/01 Highland starvationSW2001/269A M174/01 Phocoena phocoena M 143 09/12/01 Tayside necrotic gastritis/pancreatitisSW2001/270 M59/12/01 Phocoena phocoena M 178 11/12/01 Cornwall not establishedSW2001/271 M54/12/01 Delphinus delphis M 219 11/12/01 Cornwall not establishedSW2001/272 M55/12/01 Phocoena phocoena F 150 11/12/01 Cornwall physical trauma, by-catchSW2001/273 M78/12/01 Phocoena phocoena F 138 14/12/01 Cornwall physical trauma (bottlenose dolphin attack)SW2001/280 M97/12/01 Delphinus delphis F 215 21/12/01 Cornwall peritonitis, gastric parasitism (heavy)SW2001/281 M101/12/01Phocoena phocoena M 124 27/12/01 Cornwall live strandingSW2001/282 XT008/02 Phocoena phocoena F 113 28/12/01 Ceredigion parasitism, pulmonary (heavy)SW2001/284 XT007/02 Delphinus delphis M 127 31/12/01 Devon live strandingSW2001/285 M179/01 Stenella coeruleoalba F 165 31/12/01 Lothian live strandingSS2001/3 EXTERNAL Halichoerus grypus F -9 12/02/01 Dorset physical traumaSS2001/4 M013/01 Phoca vitulina U -9 31/01/01 Strathclyde starvation/gastric parasitismSS2001/7 EXTERNAL Phoca vitulina F 152 19/02/01 Essex physical trauma, by-catchSS2001/23 XT736/01 Halichoerus grypus F 124 11/07/01 Humberside physical trauma, by-catch (known)SS2001/31 M053/01 Halichoerus grypus F 101 11/04/01 Highland starvationSS2001/110 M124/01 Phoca vitulina M 93 09/04/01 Highland starvationSS2001/117 XT1146/01 Halichoerus grypus F 112 28/11/01 Pembrokeshire euthanased in rehabilitation centreSS2001/119 XT028/02 Halichoerus grypus M 117 01/12/01 Devon physical trauma, by-catchSS2001/121 M148/01A Phoca vitulina F 95 20/09/01 Highland starvationSS2001/122 M148/01B Phoca vitulina M 89 13/09/01 Highland starvationSS2001/123 M162/01 Phoca vitulina F 92 29/11/01 Orkney parasitism, pulmonary (heavy)T2001/2 XT487/01 Dermochelys coriacea M 210 21/05/01 Cornwall physical trauma, bycatchT2001/18 M157/01 Caretta caretta ? 36 18/11/01 Highland starvation/hypothermia
The Natural History Museum 85
Appendix 4: Current UK Marine Mammal Strandings Project collaborationsAppendix 4: Current UK Marine Mammal Strandings Project collaborations
Research collaborationResearch collaboration Region (England/Wales)Region (England/Wales) Region (Scotland)Region (Scotland)DNA Analyses(Harbour porpoises)
Population genetic studies at IOZand Cambridge University(under a NERC studentship)
Population genetic studies at IOZand Cambridge University(under a NERC studentship)
Teeth ageing (porpoises) SMRU Aberdeen UniversityTeeth ageing (other cetacea) SMRU/NHM Aberdeen UniversityStomach contents (porpoises) SMRU Aberdeen UniversityStomach contents (other cetacea) SMRU/NHM Aberdeen UniversityMorphometrics (skull, scapulae) Royal Museum of Scotland Royal Museum of ScotlandMorbillivirus immunoperoxidase test(all marine mammals)
Institute of Animal Health, Pirbright Institute of Animal Health, Pirbright
Brucella bacteriology & serology Central Veterinary Laboratory Central Veterinary LaboratorySerology (selected viruses) to be agreed to be agreedParasite identification NHMCetacean visual development(cetacean eyes)
Institute of Opthalmology, London Institute of Opthalmology, London
SMRU Sea Mammal Research UnitNHM Natural History MuseumIOZ Institute of ZoologyDARNIDepartment of Agriculture and Rural Development (Northern Ireland)CEFAS Centre for Environmental, Fisheries and Aquaculture Science
GUIDELINES FOR THE POSTMORTEM EXAMINATION AND TISSUE SAMPLINGGUIDELINES FOR THE POSTMORTEM EXAMINATION AND TISSUE SAMPLINGOF CETACEANSOF CETACEANS
CONTENTSCONTENTSa) Introductiona) Introductionb) Basic measurementsb) Basic measurementsc) External examinationc) External examinationd) Examination of abdominal organs (except G.I. tract, pancreas, and spleen)d) Examination of abdominal organs (except G.I. tract, pancreas, and spleen)e) Examination of organs of head, neck and thoraxe) Examination of organs of head, neck and thoraxf) Examination of the G.I. tract, pancreas and spleenf) Examination of the G.I. tract, pancreas and spleen
a) Introductiona) IntroductionThese guidelines are meant primarily as an aid to veterinary surgeons carrying outpostmortem examinations on stranded cetaceans in the U.K., as a part of theDEFRA-funded marine mammal projects in England, Wales, and Scotland. Theyare based partly on guidelines written by Dr John Baker, University of Liverpool,and partly on the protocol produced at the European Cetacean Society workshopon cetacean pathology, held in Leiden, The Netherlands, in September 1991.
All structures must be examined visually and by palpation, making incisions intothe organs. A full post mortem record must be kept, preferably on the standard"cetacean postmortem report" form.
Lesions in any organs should be described, photographed and sampled. Thedescription should include the size, location, colour, texture, shape, and the natureof the transition from normal to abnormal tissue. Photographs should include aruler or similar object to indicate the size of the lesion. According to the suspectedetiology of the lesion, samples should be collected for bacteriological examination(especially if the lesion is of a purulent nature), for virological examination, and forparasitological examination. In all cases, a sample of the lesion should bepreserved for histopathological examination.
Any parasites found, regardless if they are associated with pathological lesions ornot, should be preserved in 70% ethanol for identification. An attempt should bemade to estimate the total number of parasites. Some predilection sites forparasites are indicated in the text.
If the state of decomposition of the carcass is advanced (condition code 4 or 5,see below), only the basic measurements, organ weights (when possible), and alimited number of samples (epidermis, skull, teeth, food remains, gonads) shouldbe taken.
The postmortem examination need not take place in the order described below.However, samples for bacteriological and virological examination need to betaken as early as possible. Also, examination of the G.I. tract should be left untillast to prevent cross-contamination with enteric micro-organisms.
The Natural History Museum 87
PhotographsPhotographs
body conditionbody condition
body weightbody weight
body lengthbody length
body girthbody girth
nutritional statenutritional state
body orificesbody orifices
epidermisepidermis
milkmilk
blubberblubber
b) Basic measurementsb) Basic measurements
Photographs should be taken of the lateral views of the whole body, fromboth sides. Particularly in bottle-nosed dolphins, photographs should betaken of the dorsal fin, also from both sides. In baleen whales, the ventralside of the tail flukes should be photographed.
Estimate the body condition, that is the state of decomposition of thecarcass, using the categories of the condition code1.
Weigh the carcass. If this is not possible, the body weight can beestimated from the heart weight2.
Measure the body length by placing the carcass on its belly, holding ameasuring tape or ruler next to the carcass in a straight line parallel to thelongitudinal body axis and measuring the distance between the notch inthe tail flukes and the tip of the upper jaw. Measure the body girth at thelevel of the anterior insertion of the dorsal fin.
c) External examinationc) External examination
Indicate the nutritional state of the carcass, using one of the following 3categories:-good: the aspect of the upper flanks on either side of the dorsal fin isrounded;-moderate: the aspect of the upper flanks on either side of the dorsal fin issloping;-poor: the aspect of the upper flanks on either side of the dorsal fin ishollow (in these animals, one can make out the transverse processes ofthe lumbar vertebrae, and there is an indentation dorsally just behind thehead).
Examine the body orifices (mouth, eyes, ear openings, blow-hole, anus,genital slit and mammary slits) for lesions and any discharge. Collect andpreserve left and right eyes separately in 10% formalin (only if both eyesare fully intact).
Examine the animal for external lesions and sample these accordingly.Examine the skin carefully for any ectoparasites. These are most likely tobe found in or near the body orifices and next to the fins and flukes. Takea 4 cm2 piece of epidermis down to the blubber for DNA-studies, andfreeze.
Massage the skin in the area cranial to the mammary slits in a caudaldirection to express any fluid present in the mammary glands. If fluid canbe pressed out, collect a sample for organochlorine analysis in a hexane-washed glass container and freeze. If the lid is made of plastic, separatethe sample from this with aluminium foil. Note the volume, colour, andconsistency of the fluid.
Cut a transverse strip of blubber about 2 cm wide from the anteriorinsertion of the dorsal fin, from the mid-dorsal to the mid-ventral region.Make sure to cut at right-angles to the surface of the skin. Measure thethickness of the blubber strip with a ruler 2cm lateral to the dorsal mid-line, mid-laterally, and 2cm lateral to the ventral mid-line. (Using thismethod, the tension of the blubber tissue is relieved before measuring.)
The Natural History Museum 88
musclemuscle
mammary glandmammary gland
subcutaneous tissuesubcutaneous tissue
scapulascapula
ribrib
virology samplesvirology samples
bacteriology samplesbacteriology samples
Cut a strip of blubber a few cm wide and a few cm long at the level of thecaudal insertion of the dorsal fin. Make sure to cut at right-angles to thesurface of the skin. Measure the thickness of the blubber strip 2 cm lateralto the dorsal mid-line. From this blubber strip, take 2x20 g cross-sectionalsamples of blubber for organochlorine analysis. It is important to takesamples of the whole layer, from the skin to the muscle. Wrap them inhexane-washed aluminium foil, place them in 25 ml Universal tubes, andfreeze. Alternatively, they can be placed in Sovirel glass tubes.
Take 2x20 g muscle samples for toxicological analysis, at the samelocation as and directly below the blubber sample, at the level of thecaudal insertion of the dorsal fin. Wrap them in hexane-washedaluminium foil, place them in 25 ml Universal tubes, and freeze.Alternatively, they can be placed in Sovirel glass tubes.
With the animal on its right side make a mid-line ventral incision from thesymphysis of the mandible to a short distance posterior of the anus,circumventing the genital slit and anus. From the posterior end of theventral incision make a second one almost to the dorsal mid-line. Reflectthe skin and blubber off the uppermost side. Any parasites in the blubbershould be noted and collected. They may occur as white cysts less than 1cm in diameter, often in the ano-genital region or the dorsal aspect of thechest wall.
In females, examine the mammary gland for pathological changes andparasites. Collect a cross-sectional slice of about 1 cm thick from halfwayalong the length of the left mammary gland for histopathologicalexamination, and place in 10% formalin.
Examine the subcutaneous tissue for the presence of bruises and parasites.
Remove the left scapula for (future) radionuclide analysis and freeze.
d) Examination of abdominal organs (except G.I. tract, pancreas, andd) Examination of abdominal organs (except G.I. tract, pancreas, andspleen)spleen)
Remove the left abdominal wall, freeing the testis or ovary and uterus.Any parasites in the abdominal wall (for instance cysts under theperitoneum) should be collected. Remove the left thoracic wall, forexample with bone shears. Remove the fifth left rib and freeze a 15 cmsection of it.
Before handling the internal organs, take two 1 cm3 samples of lung tissuefrom the cranio-ventral part of the left lung and a 1cm3 sample of kidneytissue from the left kidney for virological examination. Also take a sampleof lung tissue from the cranio-ventral part of the left lung, a sample ofkidney tissue from the left kidney, a sample of liver tissue from the leftlobe of the liver, and a sample of heart blood from the right ventricle, forbacteriological examination.
Sever the intestine close to the anus and the oesophagus close to thediaphragm. Working forward along the dorsal aspect of the abdominalcavity, remove the stomach, intestines, pancreas, spleen and mesentericlymph node, attached to each other, from the carcass. Leave theexamination of the G.I. tract to the end of the postmortem examinationto prevent cross-contamination of other tissues with enteric micro-
The Natural History Museum 89
Urinary bladderUrinary bladder
female repr. tractfemale repr. tract
foetusfoetus
male repr. tractmale repr. tract
adrenal glandsadrenal glands
kidneyskidneys
liverliver
thyroidthyroid
organisms.
Open and examine the bladder in situ, noting the contents, if any.Preserve a 1cm3 sample of the bladder in 10% formalin (forhistopathology).
In females remove the entire reproductive tract, open the vagina anduterus, note any corpora lutea, corpora albicantia or follicles on eachovary and then place the ovaries separately in 10% formalin forreproduction studies. Preserve a 1cm3 sample of the uterus in 10%formalin (for histopathology).
If a foetus is present of sufficient size to examine the individual organs, apostmortem examination and tissue sampling of the foetus can take placein the same way as for cetaceans after birth. If it is too small for a fullpostmortem examination, the whole foetus and its placenta can bewrapped in hexane-washed aluminium foil and stored frozen fororganochlorine analysis.
In males remove the testes and weigh them separately after removing theepididymis. After incision and examination, place the testes in 10%formalin for reproductive studies. If they are heavier than about 50 geach, place a cross-sectional slice about 1 cm thick from mid-way alongthe length in 10% formalin. Examine the penis and preputium.
Remove and examine the adrenal glands, and place them separately in10% formalin.
Remove the kidneys from the body cavity and weigh them. Incise bothkidneys longitudinally, and if possible, strip the capsule. Then, take 2x20 gsamples for toxicological analysis from halfway the length of the leftkidney. These samples should be cross-sectional and include bothmedullary and cortical tissue. Wrap them in hexane-washed aluminiumfoil, place them in 25 ml Universal tubes, and freeze. Alternatively, theycan be placed in Sovirel glass tubes. Preserve 1 cm3 from a kidney in 10%formalin for histopathological examination.
Remove and weigh the liver. Examine both surfaces and make multipleincisions into the substance. Examine the bile ducts for parasites. Then,take 2x20 g for trace metal analysis. These samples should includeapproximately equal amounts of tissue from the edge of the left lobe, theedge of the right lobe, and the hilus of the liver. Wrap them in hexane-washed aluminium foil, place them in 25 ml Universal tubes, and freeze.Alternatively, they can be placed in Sovirel glass tubes. Place 1 cm3 of livertissue in 10% formalin for histopathological examination.
e) Examination of organs of head, neck and thoraxe) Examination of organs of head, neck and thorax
Carefully remove the superficial muscles overlying the trachea and larynxto expose the thyroid gland. Examine this tissue and preserve 1 cm3 oftissue in 10% formalin for histopathological examination.
Incise along the internal aspects of both mandibles and free the tongue.Once the tongue is free reflect it backwards and cut the hyoid bones closeto the skull.
The Natural History Museum 90
tonguetongue
oesophagusoesophagus
respiratory tractrespiratory tract
thymusthymus
serumserum
heartheart
tympanic bullatympanic bulla
Free the larynx from the sphincter muscle holding it in place and pullingthe tongue backwards incise along the neck to free the trachea andoesophagus. Then, incising dorsally and ventrally in the thoracic cavity,free the heart and lungs. Note any attachments of the lungs to thethoracic walls. This procedure should give you the tongue, larynx, trachea,oesophagus, thymus, heart and lungs all still fastened together.
Examine the surface of the tongue.
Open the oesophagus longitudinally and check for lesions or parasites.
Open the larynx, trachea and major bronchi longitudinally. Make multipleincisions into the substance of both lungs. Any parasites should becollected. Two pieces of lung (about 1 cm3) from the hilus and peripheryof the left lung, and the same from the right lung, should be collected in10% formalin for histopathological examination. The samples shouldinclude part of the major bronchial tree. Repeat this procedure, placingthe second set of samples in a separate container with 10% formalin formorbillivirus detection using an immunoperoxidase test. Open all majorbranches of the pulmonary veins and examine for the presence ofparasites. Examine the bronchial and so-called "pulmonary associated"lymph nodes. The latter can be found about halfway along the ventraledges of each lung. Cut a 1 cm thick cross-sectional slice from the middleof the left pulmonary associated lymph node, and place it in 10%formalin for histopathological examination.
Examine and weigh the thymus, if present (noting the presence of anymacroscopic cysts). Place 1 cm3 of thymus in 10% formalin forhistopathological examination.
Collect any blood present in the heart lumen, to obtain serum forserological examination. The serum, acquired by centrifugation, should bestored frozen. Even if it is haemolytic, it is still of value.
Separate the heart from the lungs by cutting through the major bloodvessels where they enter the heart. Open the left and right ventricles andatria for examination and to take out any blood clots present. Anyparasites should be collected. Weigh the heart. Cut a 1 cm thick slice ofheart tissue, to include a piece of the wall of the left ventricle and of theatrioventricular septum, and place it in 10% formalin for histopathologicalexamination.
Examine the tympanic bullae (which in cetaceans are not part of the skullbut lie free just behind the mandibles). Carefully dissect each tympanicbulla (and associated cochlea) free of their connective tissue attachmentsto the skull. Examine the internal cavity of each bulla and recover anynematodes present (with forceps). Preserve the left tympanicbulla/cochlea and right tympanic bulla/cochlea separately in 10%formalin.
If possible, remove two sets of (at least) 4 teeth from the middle of thelower jaw for ageing, and store frozen (separately). (In baleen whales, cutoff 2 baleen plates as near as possible to their basis and store frozen.)
In freshly dead carcasses (condition code 2), open the skull, and examinethe brain.
The Natural History Museum 91
teethteeth(baleen plates)(baleen plates)
brainbrain
skullskull
SpleenSpleen
pancreaspancreas
mesenteric ln.mesenteric ln.
stomachstomach
intestineintestine
The skull can be opened by making a vertical cut parallel and about 2 cmposterior to the transverse dorsal ridge which is clearly visible and palpableon top of the skull. The second cut should be made in the horizontalplane, through the occipital condyles, making sure to leave the posteriorportion of the condyles on the skull, so that the condylo-basal length canstill be measured. Both cuts should be extended until they meet eachother. The separated piece of skull can then be pried loose using a chiselor flat-bladed screwdriver, and the brain can be removed.
Take a 1 cm3 sample of brain for virological examination. Place the rest ofthe brain in 10% formalin for at least a week. To allow faster fixation, alongitudinal incision can be made in the cerebrum to expose the lateralventricles. When it is fixed, make multiple slices into the tissue to look forpathological lesions, including the presence of parasites. Take 1 cm3
samples of the cortex, midbrain, cerebellum, and medulla, forhistopathological examination. Dissect the pituitary gland from thepituitary fossa (located in the cranial floor) and preserve in 10% formalin.
In more decomposed carcasses, leave the skull intact. Both opened andcompletely intact skulls should be stored frozen for morphometricsstudies.
f) Examination of the G.I. tract, pancreas and spleenf) Examination of the G.I. tract, pancreas and spleen
Examine and weigh the spleen and put a piece (about 1 cm3), including asection of capsule, in 10% formalin for histopathological examination.One often finds smaller accessory spleens near to the main spleen.
Examine the pancreas. Look for parasites, particularly in the pancreaticducts. Place a 1 cm3 piece of pancreas tissue in 10% formalin forhistopathological examination.
Examine the mesenteric lymph node and put a 1 cm thick cross-sectionalslice from halfway its length in 10% formalin for histopathologicalexamination.
Open the cardiac section of the stomach. Collect any fish bones, otolithsand other food remains and preserve in 70% ethanol or freeze for preystudies. Any parasites should be collected. Describe any lesions, includingthe distribution and size of any ulcers.
Open the fundic and pyloric sections of the stomach. Any food materialand parasites should be preserved as for the cardiac section. Any nodulesin the walls of the fundic and pyloric sections should be noted and, if theyare found, attempts should be made to express the contents. Anyparasites found in the contents should be collected.
Free the intestine from the mesentery and open the entire length of theorgan collecting any contents in a bucket. The contents should be dilutedwith water and sieved through a 500 �m sieve to collect otoliths and otherrecognisable food remains. These should be stored in 70% ethanol (oralternatively stored frozen). Any parasites should be collected.
The Natural History Museum 92
AA. The body condition, or state of decomposition of a carcass, can bedescribed using the following condition code:
1) live (becomes code 2 at death)
2a) extremely fresh (as if just died, no bloating, meat is considered bymost to be edible)
5) indeterminate (mummified carcass or skeletal remains, no organspresent)
B The body weight can be estimated from the heart weight using theformulalog W = (log H + 2.2) / 0.984, with H = heart weight and W = bodyweight, both in kg.
