R.V. Celtic Explorer – OSS Oceanographic Survey 2010
Cetacean Distribution & Relative Abundance Survey
16th May – 22nd May 2010
Surveyor: Dave Wall
Ship Surveys Programme Irish Whale and Dolphin Group Marine Biodiversity Research Group Galway-Mayo Institute of Technology
Basking sharks (© Dave Wall)
Introduction
The waters of Ireland’s Exclusive Economic Zone (EEZ) are thought to represent
one of the most important cetacean (whales, dolphins and porpoise) habitats in
Europe. To date 24 species of cetacean have been recorded (Appendix I), with
seven of these having been confirmed as calving within the Irish EEZ, while a
number of other species are possibly calving (e.g. minke whale and northern
bottlenose whale) (Berrow 2001). In recognition of their importance for
cetaceans, the Irish government declared all Irish waters (within the EEZ) to be a
whale and dolphin sanctuary in 1991 (Rogan and Berrow 1995). Despite this
recognition, information on the distribution and relative abundance of cetaceans
within the Irish EEZ, especially in offshore waters, is very limited (Wall et al.
2006).
The Irish Whale and Dolphin Group (IWDG) have been collecting data on the
distribution and relative abundance of cetaceans in Irish waters (including
Northern Ireland) since 1991. The IWDG casual and constant effort sightings
schemes record data mainly from land-based sightings and surveys (Berrow et
al. 2001). The IWDG has conducted cetacean surveys on board commercial
ferries since 2001, on board research vessels since 2003 and on board naval
service vessels since 2008.
In 2008, the IWDG in collaboration with the Galway-Mayo Institute of
Technology commenced PReCAST, a three-year project (2008-2011) which aims
to provide robust scientific data to support conservation policy and provide
guidance to state agencies in implementing national and international
obligations. PReCAST is committed to gaining a more complete understanding of
the seasonal distribution, relative abundance and habitat use of cetaceans within
the Irish EEZ.
As part of this project a cetacean distribution and relative abundance survey was
conducted on board the Marine Institute vessel Celtic Explorer during the OSS
Oceanographic Survey from 16th – 22nd May 2010.
Methods
The survey was conducted on board the Marine Institute vessel Celtic Explorer
during the OSS Oceanographic Survey between the 16th and 22nd May 2010. The
survey area covered waters over the Irish Shelf to the west and south of Ireland.
The survey areas were opportunistic and based on survey transects chosen for
the OSS Oceanographic Survey 2010.
Visual Survey
A single marine mammal observer was present on board during the survey and
conducted watches from the ships crow’s nest located 18m above sea level.
Observer effort focused on a 90-degree arc ahead of the ship; however sightings
located up to 90 degrees to port and starboard were also included. The observer
scanned the area by eye and using 10 X 40 binoculars. Bearings to sightings were
measured using an angle board and distances were estimated with the aid of
distance measuring stick. Environmental data were recorded every 15 minutes
using Logger 2000 software (IFAW 2000). Sightings were also recorded using
Logger 2000. Automated position data were obtained through a laptop computer
linked to GPS receiver.
As this was a survey onboard a vessel of opportunity, the survey was conducted
in ‘passing mode’ and cetaceans sighted were not approached. Sightings were
identified to species level where possible, with species identifications being
graded as definite, probable or possible. Where species identification could not
be confirmed, sightings were downgraded (e.g. unidentified dolphin /
unidentified whale / unidentified beaked whale etc.) according to criteria
established for the IWDG’s cetacean sightings database (IWDG 2010).
Passive Acoustic Survey
A towed hydrophone setup was used onboard the Celtic Explorer. This consisted
of a 200m array having two elements separated at 25cm and no depth sensor.
This MagRec built hydrophone had its elements refitted by the Sea Mammal
Research Unit (SMRU), St. Andrew’s, Scotland in August 2009. Two channels
were sampled at 140 ks/sec, providing a 2-70 kHz frequency range. The acoustic
array was connected to a MACREC LTD HP-27st bufferbox. The output from the
buffer-box was fed to a laptop with a Realtek HD Soundcard.
This laptop used IFAW´s Logger (ver. 4.06.0001), RainbowClick (ver. 4.08.0001)
software and PAMQUARD (ver. 1.5.01) Beta software for data acquisition and
click detection. An external GPS unit provided GPS data to the set-up. A 2 TB
hard drive provided storage and backup facility for the data collected. Raw
recordings and click files were stored on the laptop and backed up to the hard
drive every day.
During transects the hydrophone was deployed and monitored by a single
observer for the majority of the deployment time. Raw recordings and click files
were stored to the laptop and backed up to hard drive for later analysis.
Results
Environmental Conditions
Environmental data was collected at 131 stations. Sea state was ≤ 3 at 84.7% of
environmental stations, ≤ 4 at 91.6% of stations and ≤ 5 at 100% of stations.
Visibility was >5km at 28.2% of stations and 1–5km at 55% of stations and 500-
1000m at 12.9% of stations. Rainfall was recorded at 4.5% of stations and
fog/mist was recorded at 75.6% of stations (fig. 1). One full days of survey effort
and one half day were lost due to bad weather (sea state 6 or more) and/or the
dense fog.
Figure 1. Sea state, swell conditions and visibility recorded twice daily during days on survey.
Cetacean Visual Survey Results
30.4 hours of survey time were logged with 83.6% (25.4 hrs) of this at Beaufort
sea state three or less; 91.4% (27.8hrs) at Beaufort sea state four or less and
100% at Beaufort sea state five or less. 38 sightings of three cetacean species and
one seal species, totalling 170 individuals were recorded (fig. 2).
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Sea State (Beaufort)
Visibility (0-4)
Swell (0-3)
Figure 2. Distribution and group size of cetacean species recorded during the survey.
Figure 3. Distribution and group size of cetacean species recorded during the survey.
Identified cetacean species were common dolphin (Delphinus delphis), harbour
porpoise (Phocoena phocoena) and minke whale (Balaenoptera acutorostrata).
Grey seals (Halichoerus grypus) were sighted in offshore shelf waters, with
feeding noted in several cases. Two basking sharks (Cetorhinus maximus) were
also sighted, west of Aranmore, one of which breached close to the ship.
Table 1. Sightings, counts and group size ranges for cetaceans sighted during the visual survey.
Species
No. Sightings
No. Individuals
Range of Group Size
Juveniles/ Calves
Common dolphin 10 129 2-20 2
Harbour porpoise 14 25 1-3 -
Minke whale 2 2 - -
Grey seal 11 12 1-2 -
Cetacean Passive Acoustic Survey Results
46 hours of acoustic time were logged during the survey. Most of this effort was
conducted with an observer monitoring the software and noting acoustic
detections as they happened. All hydrophone recordings were saved and will
undergo a full re-analysis of all the acoustic data recorded during the survey.
Following preliminary analysis, a total of 47 identified acoustic detection events
were logged (table 2). As these results were based on a preliminary analysis of
the data, changes in the final dataset should be expected.
Table 2. Acoustic detections recorded during the Cetacean Passive Acoustic Survey.
Species
No. Detections
Common Dolphin 2
Unidentified dolphin whistles 29
Unidentified dolphin clicks 16
Fig. 4 Distribution of dolphin acoustic detections recorded during the survey.
The only confirmed species detected was common dolphin (fig. 4). All dolphin
acoustic detections where species was not confirmed by a sighting were classes
as unidentified dolphins, pending further analysis of the data.
Bird Activity
Daily species lists were made of all seabird species seen around the survey
vessel. 13 seabird species were recorded during the survey: arctic tern (Sterna
paradisaea), guillemot (Uria aalge); razorbill (Alca torda), puffin (Fratercula
arctica), gannet (Morus bassanus); fulmar (Fulmarus glacialis); manx shearwater
(Puffinus puffinus), kittiwake (Rissa tridactyla); lesser black backed gull (Larus
fuscus); great skua (Stercorarius skua), pomarine skua (Stercorarius pomarinus),
storm petrel (Hydrobates pelagicus) and great northern diver (Gavia immer).
References
Berrow, S.D., Whooley, P. and Ferriss, S. (2001) Irish Whale and Dolphin
Group cetacean sighting schemes: development of a system to record sightings of
cetaceans (whales, dolphins and porpoises) in Irish waters. Final report to the
Heritage Council (Ireland), Kilkenny.
IFAW (2000) Logger 2000 software. Inter-national Fund for Animal Welfare,
London.
IWDG (2009) IWDG Cetacean Sightings Database (Rep. Ireland & Northern
Ireland). http://www.iwdg.ie/Iscope/
Ó Cadhla, O., Mackey, M., Aguilar de Soto, N., Rogan, E. & Connolly, N. (2004).
Cetaceans and Seabirds of Ireland’s Atlantic Margin. Volume II – Cetacean
distribution & abundance. Report on research carried out under the Irish
Infrastructure Programme (PIP): Rockall Studies Group (RSG) projects 98/6 and
00/13, Porcupine Studies Group project P00/15 and Offshore Support Group (OSG)
project 99/38. 82pp.
Rogan, E. and Berrow, S.D. (1995) The management of Irish waters as a whale
and dolphin sanctuary. In A.S. Blix, L. Walløe and Ø. Ulltang (eds), Whales, seals,
fish and man, 671..81. Amsterdam. Elsevier Science.
Wall D., O’Brien J., Meade J. & Allen B.M. (2006) Summer distribution and
relative abundance of cetaceans off the west coast of Ireland. Biology and
Environment: Proceedings of the Royal Irish Academy, 106B (2), 135 - 142.
Previous Survey Reports
Wall D. (2010) Cetacean Distribution and
Relative Abundance Survey during FRS Mackerel
Egg Survey 2010. Report to the Fisheries Research
Services, Aberdeen, Scotland.
Wall D. (2010) Cetacean Distribution and
Relative Abundance Survey during FSS Mackerel
Egg Survey 2010. Report to the Marine Institute,
Oranmore, Galway, Ireland.
Wall D. et al. (2010) Cetaceans on the Frontier
Survey 2010. Cruise report to the Marine Institute,
Oranmore, Galway, Ireland.
O’Brien J. (2010) Cetacean Distribution and
Relative Abundance Survey during the Marine
Institute Oceanographic Survey 2010. Report to
the Marine Institute, Oranmore, Galway, Ireland.
Wall D. (2010) Cetacean Distribution and
Relative Abundance Survey during the LE Roisín
& LE Niamh January Patrol 2010. Cruise Report to
Irish Naval Service, Haulbowline, Cork, Ireland.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during FSS
Deepwater Survey 2009. Report to the Marine
Institute, Oranmore, Galway, Ireland.
O’Brien J. (2009) Cetacean Distribution and
Relative Abundance Survey during FSS
Groundfish Survey 2009. Report to the Marine
Institute, Oranmore, Galway, Ireland.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during FSS
Southwest Herring Acoustic Survey 2009. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. and O’Brien J. (2009) Cetacean
Distribution and Relative Abundance Survey
during the NPWS Geogenic Reef Habitat Mapping
Survey 2009. Cruise Report to the National Parks
and Wildlife Service, 7 Ely Place, Dublin 2.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the AFBI
Autumn Herring Acoustic Survey 2009. Cruise
Report to the Agriculture, Food and Biosciences
Institute, Belfast.
Wall D. et al. (2009) Cetaceans on the Frontier
Survey 2009. Cruise report to the Marine Institute,
Oranmore, Galway, Ireland.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the AFBI
Biological Oceanography Survey 2009. Cruise
Report to the Agriculture, Food and Biosciences
Institute, Belfast.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the AFBI
Nephrops Survey 2009. Cruise Report to the
Agriculture, Food and Biosciences Institute,
Belfast.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the AFBI
Summer Herring Acoustic Survey 2009. Cruise
Report to the Agriculture, Food and Biosciences
Institute, Belfast.
Kavanagh L. (2009) Cetacean Distribution and
Relative Abundance Survey during FSS
Northwest Herring Acoustic Survey 2009. Cruise
Report to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during the NUI
Galway, Climate Change Survey 2009. Cruise
Report to National University of Ireland, Galway,
Ireland.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the AFBI
Juvenile Gadoid Survey 2009. Cruise Report to the
Agriculture, Food and Biosciences Institute,
Belfast.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during the NUI
Galway, Coralfish Survey 2009. Cruise Report to
National University of Ireland, Galway, Ireland.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during the LE Emer
April Patrol 2009. Cruise Report to Irish Naval
Service, Haulbowline, Cork, Ireland.
O’Brien J. (2009) Cetacean Distribution and
Relative Abundance Survey during the Tridens
Blue Whiting Survey 2009. Report to the Dutch
Ministry of Agriculture, Nature and Food Quality
(LNV), Den Haag, The Netherlands.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the AFBI
Groundfish Survey 2009. Report to the
Agriculture, Food and Biosciences Institute,
Belfast.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during the Marine
Institute Oceanographic Survey 2009. Report to
the Marine Institute, Oranmore, Galway, Ireland.
Tuffy P. (2009) Cetacean Distribution and
Relative Abundance Survey during AFBI Gadoid
Survey 2009. Report to the Agriculture, Food and
Biosciences Institute, Belfast.
Murray C. (2009) Cetacean Distribution and
Relative Abundance Survey during the Marine
Institute Nutrient Survey 2009. Report to the
Marine Institute, Oranmore, Galway, Ireland.
Wall D. (2009) Cetacean Distribution and
Relative Abundance Survey during the LE Niamh
January Patrol 2009. Report to Irish Naval Service,
Haulbowline, Cork, Ireland.
Wall D. (2008) Cetacean Distribution and
Relative Abundance Survey during the LE Róisín
December Patrol 2008. Report to Irish Naval
Service, Haulbowline, Cork, Ireland.
Tuffy P. (2008) Cetacean Distribution and
Relative Abundance Survey during IFREMER
Groundfish Survey 2008. Report to the French
Institute for the Exploitation of the Sea.
Murray C. (2008) Cetacean Distribution and
Relative Abundance Survey during CEFAS
Groundfish Survey 2008. Report to the Centre for
Environment, Food and Agriculture Sciences,
Suffolk, England.
Tuffy P. (2008) Cetacean Distribution and
Relative Abundance Survey during AFBI
Groundfish Survey 2008. Report to the
Agriculture, Food and Biosciences Institute,
Belfast.
Wall D. (2008) Cetacean Distribution and
Relative Abundance Survey during FSS
Southwest Herring Acoustic Survey 2008. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2008) Cetacean Distribution and
Relative Abundance Survey during FSS Deep
Water Survey 2008. Report to the Marine
Institute, Oranmore, Galway, Ireland.
Murray C. (2008) Cetacean Distribution and
Relative Abundance Survey during AFBI
Nephrops Assessment Survey 2008. Report to the
Agri-Food and Biosciences Institute, Northern
Ireland.
Wall D. (2008) Cetacean Distribution and
Relative Abundance Survey during NIOZ Cold
Water Coral Fish Survey 2008. Report to the
Royal Netherlands Institute for Sea Research and
the Marine Institute, Oranmore, Galway, Ireland.
Wall D. (2008) Cetacean Distribution and
Relative Abundance Survey during FSS Blue
Whiting Acoustic Survey 2008. Report to the
Marine Institute, Oranmore, Galway, Ireland.
Baer J. (2008) Cetacean Distribution and
Relative Abundance Survey during CEFAS Irish
Sea Plankton Survey 2008. Report to the Centre
for Environment, Fisheries & Aquaculture Science
and the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2007) Cetacean Distribution and
Relative Abundance Survey during FSS
Southwest Herring Acoustic Survey 2007. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2007) Cetacean Distribution and
Relative Abundance Survey during FSS Deep
Water Survey 2007. Report to the Marine
Institute, Oranmore, Galway, Ireland.
Wall D. (2007) Cetacean Distribution and
Relative Abundance Survey during NIOZ Canyons
Survey 2007. Report to the Royal Netherlands
Institute for Sea Research and the Marine
Institute, Oranmore, Galway, Ireland.
Wall D. (2007) Cetacean Distribution and
Relative Abundance Survey during Rockall
Trough Oceanographic Survey 2007. Report to
the Marine Institute, Oranmore, Galway, Ireland.
Wall D. (2007) Cetacean Distribution and
Relative Abundance Survey during FSS
Northwest Herring Acoustic Survey 2007. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2006) Cetacean Distribution and
Relative Abundance Survey during FSS
Southwest Herring Acoustic Survey 2006. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2006) Cetacean Distribution and
Relative Abundance Survey during FSS Deep
Water Survey 2006. Report to the Marine
Institute, Oranmore, Galway, Ireland.
Wall D. (2005) Cetacean Distribution and
Relative Abundance Survey during FSS
Southwest Herring Acoustic Survey 2005. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
Wall D. (2005) Cetacean Distribution and
Relative Abundance Survey during Irish Seabed
Survey: Leg 17. Report to the Marine Institute,
Oranmore, Galway, Ireland.
Wall D., O’Brien J., Meade J. & Allen B.M.
(2004) Summer Distribution and Relative
Abundance of Cetaceans off the West Coast of
Ireland. Final report to the Heritage Council,
Kilkenny, Ireland.
O’Brien J. (2004) Cetacean Distribution and
Relative Abundance Survey during FSS
Northwest Herring Acoustic Survey 2004. Report
to the Marine Institute, Oranmore, Galway,
Ireland.
O’Brien J. (2004) Cetacean Distribution and
Relative Abundance Survey during FSS Blue
Whiting Survey 2004. Report to the Marine
Institute, Oranmore, Galway, Ireland.
Wall D. (2004) Cetacean Distribution and
Relative Abundance Survey during the Celtic Sea
Herring Acoustic Survey 2004. Report to the
Marine Institute, Oranmore, Galway, Ireland.
All reports are available online at:
www.iwdg.ie/shipsurveys/
Appendix I: List of cetacean species recorded within the Irish EEZ and
adjacent waters.
Atlantic White-Sided Dolphin Lagenorhynchus acutus
Beluga Delphinapterus leucas†
Blue Whale Balaenoptera musculus
Bottlenose Dolphin Tursiops truncatus
Common Dolphin Delphinus delphis
Cuvier's Beaked Whale Ziphius cavirostris
False Killer Whale Pseudorca crassidens
Fin Whale Balaenoptera physalus
Gervais’ Beaked Whale Mesoplodon europaeus*
Harbour Porpoise Phocoena phocoena
Humpback Whale Megaptera novaeangliae
Killer Whale Orcinus orca
Minke Whale Balaenoptera acutorostrata
Northern Bottlenose Whale Hyperoodon ampullatus
Northern Right Whale Eubalaena glacialis
Pilot Whale (long-finned) Globicephala melas
Pygmy Sperm Whale Kogia breviceps
Risso's Dolphin Grampus griseus
Sei Whale Balaenoptera borealis
Sowerby's Beaked Whale Mesplodon bidens
Sperm Whale Physeter macrocephalus
Striped Dolphin Stenella coeruleoalba
True's Beaked Whale Mesplodon mirus
White-Beaked Dolphin Lagenorhynchus albirostris
† Vagrant * Recorded only from Stranding