THIS PAPER NOT Ta BE CITED WITHOUT PRIOR REFERENCE TOTIIE AUTHOR

International Couneil forthe Exploration of the Sea

THE DOMINANT FISH FAUNA IN THENORTH SEA ANDITS DETERMINATION

Yang Jiming*Ministryof Agrieulture, Fisheries and FoodDireetorate of Fisheries ResearchFisheries Laboratory, LowestoftSuffolk, NR33 OHT, England

CM 1981/G:16Demersal Fish CommitteeRef. Pelagie Fish Committee

ABSTRACT,

Aeeo~ding to Wheeler (1978 and personal eommunieation), there are

,~ eonsidered to be three fish faunas in the North Sea eontributing a total

of 224 fish speeies.

An analysis was done by both the number of speeies (Ekman's 1953

method) and the biomass of eaeh fish fauna. Though the' Lusitanian fish

fauna is riehest in number of species - 49.1% of total speeies, the Boreal

fish fauna reaehes the highest biomass - 53.8% of total biomass.

Therefore the dominant fish fauna in the'North Sea is theBoreal one, and

biomass is the better index to judge domiriant fauha rather than the number

of speeies.

RESUME

Selon WHEELER (1978 et eommunieation personnel) il y aurait trois

faunes halieutiques dans la mer du Nord, reunissant un total de '224

especes. , .~ ..

On a effeetue une analyse du nombre d'espeees (methode d'E~1AN, 1953)

ainsi que de 1a biomasse de ehaque faune. Quoique 1a faune lusitanienne

soit 1a plus riehe au niveau dunombre d'espee~s - 49. 1% du total des

especes - 1a faune boreale represente 1a'biomasse 1a plus imporante ­

53.8%de 1a biomasse totale. La faune halieutique dominante de ,la mer du

Nord est ainsi 1a boreale et la biomasse fournit un meilleur element

d'appreeiation de la faune dominante que le nombre d'espeees.

*Permanent address: ' Institute of Oeeanology, Aeademia Siniea,7 Nan-Hai Road, Tsingtao, The People's Republie of'China.

1

'"

lNTRODUCTlON ~ ,,' .t.

., 1

Sinee Ekman (1953) the basic method of establishing. zoogeographie

regions and boundaries~'has J be~n based on the assessment of the number of

species wf.thin a fauna, whieh has been used by a number of authors .(Chu

and Wu, 1965; Briggs, 1974; Whee1er, 1978; and others)~ However, as 'our .'

know1edge of the anima1s in the sea has inereased it has beeome obvious

that biomass of a speeies may vary·great1y.both in,p1aee andtime and nay

also show differenees when two areas are eompared.' U11s "raises the

interesting possibility that evaluation of the eomponents of the bioaass

of ·a given systematic group within a geographieal region might produee a

truer ref1cetion of its geographiea1 affinities than a study based sicp1y

upon numbers of speeies. The present work attempts to make a eomparison .

between the tWQ methods ,and to establish the dominantfish fauna in the

. North Sea.

METHOD

The estimation of biomass within so 1arge an area as the North Sea

was impossible in,~he past and.is diffieu1t today•. However. theauthor

has made an estimate of .the fish.biomass in the,NorthSea, CM 1981/G:15. .

(Yang, 1981), and,an assessment of the faunistie affinitles of the speeies. " . '. . - .

has been obtained:from Wheeler (19~8, and personal eommunieation) and

B1aeker (personal eommunieation).

Six eategories of oeeurrenee or relative abundanee bf all North Sea

fish speeies eanbe derived from the literature (Day, 1880-1884; Jenkins,

1936; Haeer, .1966; Rae and Pirie, 1966,.1967a·,b,e, 1968a,bj :Blaeker~

1971, 1973; Whee1er. and.B1aeker, 1969; Whee1er, 1969,1978; lCES, 1951­

1981, and others) and estimates of biomass CM 1981/G:15 (Yang, 1981) as

follows:

•

CategoryDominantAbundantModcrate1y abundantFrequentRare, )

. Vagrant* ) :

Biomass· (thousand·tonnes)> 200

50-200 .10-502-10

<2,"-' .

Aeeording to .Wheeler (l978,.:and persona1.eommunieation), North Sea

fishes ean be eonsidered to represent three Hsh faunas: Boreal (thc dis­

tribution of these speeies is eentred north of the English Channel),

Lusitanian (the distribution of these speeies is eentred south of the

*Vagrant is used to deseribe speeies which oecur oeeasionally in the NorthSea, perhaps as a resu1t of unusual hydrographie.eonditions or aberrant

migrations.

2

'e

. '

,

l.

English Channel) and Atlantie (these speeies are widely distributed in the

Atlantie Oeean).

A total of' 224 species are" r~eord~d from the North Sea (Oay, 1880-:­

. 1884a,b; Jenklns, 1936; 'R<1e"and Pirie, 1966, 1967a~b,et 1968a,b; Blaeker,

1968a,b, 1971~'1973;: Wheeie~: 1969;' 1978;' whe~ier'and'Blaeker, 1969;

Wheeler'et 'al., 1975). Assessment'of the faunal affinity of these

speeiescan be based on the known total range of the sp~eies and its

abundanee in the North'Sea.' Most'of themf~ll elearlY into the one fauna1

eategory 'or'another; but ailoe~Üon'of a'few species,' for example, the

lampern and the flounder~"'to'one fauna ~Jther than another is arbltrary.

Tberefore, 66 speeies such ~s starry ray,herring, eod, Raitt's sandeel

and butter fish are alloeated to the Boreal fauna (Table 1), 110 speeies

such as pile~ard, whiting, hake, bass, ete. are elassified as LUsitanian

. (Table 2), and 48 speeies 'such as hagfish, ratfish; spurdog, salmon, blue­

fin tuna, sunfish and the remaining speeies are grouped into the Atlantie

fauna (Table 3).

OISCUSSlON ,

Table 4 shows a camparisan of both methods of judging the eomposition

of the fish fauna in the North Sea. Tbe two methods result in different'

eonelusions. Judging,by the index of the' number of speeies, the

Lusitanian,fauna is the riehest, possessing'49.1%:of total speeies; the~

Boreal fauna possesses only 29.5% of the total and the figure for the

Atlantie fauna is similar.' However,' jud~ing :bV biOlnass; the Boreal faunaI< ,I .~' ,"," ' • •

'has' the highest at' 53.8% of total biomass, the L\1sitanianfauna is

represented by 36.6% and thc Atlantie fauna by only 9.6% of the total •

As 'biomass cf fish i~ 'of,p~ime cancern to the fisheries of any area,

the assessmcnt of zoogeographie affinities by biomass estimates is of,

greater slgnifleanee than.oneba~~d on p~o~ori:1on:of spedes. This,

elearly, is also true of any study involving the eeologieal inter­

relatioriships cf the fauria~ Applicatiod of' bio~ss estimates' to the North

Sea shows that the dominant faunistie element is the Boreal, that the. ' ,,' .. " . ,

Lusitanian element is eorisiderable, butits importanee is enhaneed by the

abundanee of only four speeies, sprat, whiting, grey gurnard and plaiee,

and tliat' thc Atlantic e~e~ent is'" ~kall ~ith 'the only important,

eontributions to the biomass being spurdog a~dmackerel'

: ..

," ,

3

) . '"

ACKNOWLEDGEMENTS

This work was carried out unde~ ,~he ex~hange agreement between the

Royal Society and Academia Sinica. I,~ in~ebted to Dr:D.H.Cus.h~ng, F.R.S.,

Dr D.J. Garrod and Hr J.G. Pope who arranged fffj research work at' the, .. , ~ .. \ ~

Fisheries Laboratory, Lowestoft. Sincere thanks are due ,to Mr,A.C. Wheeler, ,'. ' . ~ ., '

and Mr R. Blacker who kindly provided information and personal communi-.' . '. -,.; , .

cations about the North Sea Hsh fauna,~md madeveryvaluable comments on

the draft manusc;ipt.' Special thank~ a~e~also,due to'Prof. ChuYuan-ting

who endorsed my nominati~n for '~articipation iri ,the ,ex~hange sCheme and to- " .",.. •• ~. , , " - • ~ «

Mr'A.R. Margetts ~ho provided assistanc~ wi~h fffj work.

REFERENCES '; , .

BLACKER, R.W., 1968a. English observations on rare fishesin 1966. Annls, biol. Copenh., 23, 212-13.

BLACKER, R.W., 1968b. English observations on rare Hshes in 1967. Annlsbiol. Copenh., 24, 202-03~ , " , .

BLACKER, R.W., 1971. English observations on rare fishes in 1967. Annlsbiol. Copenh., 27; 193-95~

BLACKER, R.W.,' 1973. ,English observations on rare fishin 1971.bioi., Copenh., 28, 221-22. " " .

" ;;,.

Annls

BRIGGS, J. C., 1974. Marin~~o~geogr~phy~ ,McG~aw-Hill Book Company, NewYork, 475' pp. ' '

Clro YUAN-rING and WUHAN-LING, 1965., A,preliminary. study of thezoogeography of the gobioid fishes of,China~ Oceanologia Limnol. Sin.,7. (2), 122-40~ ,'" ,; , .

DAY, F., 1880-84a. The fishes of Great Britain.and Ireland. Vol. 1.Williams and' Norgate, London, 336 pp. ~ 93 pI.'

DAY, F., 1880-84b. The fishes of Great Britain and Ireland. Vol. 2.Williams and' Norgate, u>ndon,' 388' pp:'~ . 8!l pI.

EKMAN, S., 1953. Zoogeography of the sea. S~dgw~ck and Jackson Limited,London, 417 pp.

·ICES, 1951-1981. Bulletin s.tattstiq~~~ yo~s~ ~2-63 (for the years 1947~1978).

JENKINS, J.T., 1936. The fishes of the British Isles, both freshwater andsalto Frederlck warne' & co.' Ltd~ Lon~ön. 408 pp.

;.' .

HACER, C.T., 1966. Sand' eels '(Ammodytidae) in the southern-western NorthSea; their biology and flshery. 'Flshery lnvest., Lond., Ser~ 2,24(6), 1-55. ' .... ' ., .

RAE, B.B. and PIRIE, S.F., 1966. Rare fish~s. Scott. Fish. Bull., 26,31-2. .

4

RAE, B.B. and PIRIE, S.F., 1967a. Scottish observations on rare fish in1965. Ann1s. bio1. Copenh., 22, 186.

RAE, B.B. and PIRIE, S.F., 1967b. Rare fishes. Scott. Fish. Bu11., 27,31.

RAE, B.B. and PIRIE, S.F., 1967c. Rare fishes. Scott. Fish. Bull., 28,30-1.

RAE, B.B. and PIRIE, S.F., 1968a. Scottish records of rare fish. Annlsbiol. Copenh., 23, 212,

RAE, B.B. and PIRIE, S.F., 1968b. Scottish records of rare fishes. 1967Annls biol. Copenh., 24, 201-2.

WHEELER, A., 1969. The fishes of the British Isles and North-West Europe.MacMillan, London, 613 pp.

WHEELER, A.., 1978. Key to the fishes of North Europe. Frederick Warne,London, 380 pp ••• WHEELER, A. and BLACKER, R.W., 1969.British Seas in 1966 and 1967.

Rare and litt1e-known fishes inJ. Fish. Bio1. (1969), 1" 311-31.

WHEELER, A., BLACKER, R.W. and PIRIE, S.F., 1975. Rare and 1itt1e knownfishes in British seas in 1970 and 1971. J. Fish. Bio1., ~ 183-201.

YANG JIMING, 1981. An estimate of the fish biomass in the North Sea.lCES CM 1981/G:15, 20 pp (mimeo.).

5

Iable Boreal fish species recorded and their abundance.in the North Sea.Key: D· Dominant, A • Abundant, M = Moderately abundant,

F = Frequent, Ra Rare, V • Vagrant, + • less than 0.1 orbeing ignored .

Fish species Oeeur- Biomass*~renee ('000 ton::u~~)

123456789

_ 10

-li1213141516171819202122232425262728

_29-30

3132333435363738394041424344451.647484950

Lamprey? LampernGreenland sharkStarry raySkateBlaek skateShagreen rayRound skateHerringUoutingTroutCharrGreater argentineSmelt (Sparling)CapelinCodHaddoekl~orway poutSaithe (Coalfish)Torsk (Tusk)Five-bearded roeklingllorthern rocklingFour-bcarded roeklingLingBlue lingTadpole HshViviparous blennyVahl 's eelpoutEsmark's eelpoutSars's eelpoutRough rat-tailStick1cbackFifteen-spined sticklebaekRed-fishNorway haddoekTwo-horn seulpinAtlantie hook-ear sculpinMoustache sculpinBull-routSen seorpionNorway bullheadHooknoseLuopouckerSea-suaHMontagu's sea-snailCatfish (Wolffish)Spotted eatHshJelly eatYarrell's blennySnake b lenny

/ .Petromyzon mal"-z..nusLampetra j2uviatiZisScmnwsus microcephaZusRaja radiataRaja batis'Raja nidarosiensisRaja tu7.ZonicaRaja fyZ,ZaeCZupea harengusCoregonus o:cyrinchusSalino truttaSaZveUnus aZpinusAJ:Ogentina situsOamerus eper ZanusMaZZotus viZZosusGailus morhuaNe Zanogramrrus aegZefinusTrisopterus esmarkiiPoZZachius virens' '"13l'osme brosmeCiZiata Tmlste ZaCiZiata septentrionatisEnchetyopus cimbriusMo Zva mol,vaMoZva dypterygiaRaniceps raninusZoarces vivipal'USLycodes vahU iLycodes esmarkiiLycencheZys sarsiiMacrourus bergZaxGasterosteus acuZeatusSpinachia spinaohiaSebas tes m::rrinusSebastes viviparusIce tus bicornisAJ:OtedieZZus atZanticusTztigZOpD rnu.rrayiMyoxocepnal,us ccorp1u.STauru 'Lus buba UsTauruZus UUjebol'gi11gonus catapr.ract'o.leCyc Zcpte!'Us ZumpusLir;m.·is UpariaLiparis montaguiArzarhichas lupusAnarhwhas mil1Ol"Anarhwhas denticut.atußChirolophis asaaniiLumpcnua ZampretaeforrnitJ

RRVDF·RMVDRRRARVDDD

'DMFRFMRRFRRRRFRRFRRRFFRRRRRM

RVRR

+++

453.14.3+

11.9+

250.6+0.4+

114~0

1.5+

386.8243.4591.6595.3

12.1++2.1

34.40.1++++++++0.25.5++0.5+++0.60.3++

22.9+++0.2

Table 1 (continued)

Fish species Occur- Biomass*rence ( '000 tonnes)

51 Spotted snake.blenny52 Butterfish53 Sandeel54 Raitt's sandeel55 Greater sandeel56 Fries goby .57 Diminutive goby58 Guillet's goby59 Jeffrey's goby60 Norwegian topknot61 Dab62 Lemon sole63 Witch64 Long rough dab65 Halibut66 Greenland halibut

Total 66 species

Leptoc'tinus macuZatus RPhoUs gunnel.Zus R?Arrrnodytes tobianus. FArrmodytes mt:ll'inus DHyperopl.us ZanoeoZatus ALesuerigobius J't'iesii FLebetus sCOl'pioides FLebetus guil.l.eti RBuenia jeftreysii RPhrtynorhombus norvegicus RLimanda l.imanda DMiCrostomus kitt AGl.yPtocephaZus cynogl.OS8Us MHippog'Lossoides ptatessoides DHippogl.ossus hippogl.OS8US FReinhardtius hippogl.ossoides R

+0.2

.+1180.7131.4

6.0+?+

.++

744.2178.731.4

227.26.20.1

5237. 9t·

*Mean of the biomass on 1 January in 1977 and 1978.tContributions from minor species (+) ignored.

•

Tablc 2 Lusitanian fish species recorded and their abundance in the North Ses.,Key: D • Dominant, A • Abundant, M a Moderately abundant,

F a Frequent, R • Rare, V • Vagrant, + • less than 0.1 orbeing igilored

FLah species Occur- Biomass*rence ( t 000 tonnes)

I Dogfish" Scyl-iorhinus canicuZa M 12.42 Nursehound ScyZiorhinus ateZZaris R +3 Black-mouthed dogfish GaZeus meZastamua F 2.14 Tope . GaZeorhinus gaZcus F 3.05 : Smooth hound .. Muste tus rruste tus. R +6 Starry smooth hound MusteZua asterias F +7 Monkfish Squatina aquatina V +8 Marbled electric ray Torpedo marmorata V +9 Electric ray Torpedo nobiZ,iana V +

10 Blonde ray Raja brachyura R +11 Roker Raja c Zavata F 6.612 Small-eyed ray Raja microceZZata V +13 Spotted ray Raja montagui F 7.514 Long-nosed skate Raja cxr:yrinchus R +15 Sandy ray Raja circuZaris M 14.716 Cuckoo ray Raja' r.a6VUS A 98.717 Undulate ray RajaunduZata V +18 Stingray Dasyatia paGtir~ca R +19 Eagle ray MyZiobatis aquiZa V +20 Sturgeon Acipenser sturio R +21 Moray Muzaaena he l.ena V +22 Conger Conger conger R 0.523 Sprat Sproattus sprattus D 755.324 Pilchard sardina piZc~uG R +25 Twaite shad AZosa fa ZZa:t: R +26 AlUs shad AZosa .aZosa· R +27 Anchovy EngrauUs encrasicolus 'R +28 Argentine Argentina sphyraena D 287.629 Two-spotted clingfish DipZecogaster bimacuZata R +

• 30 Angler (Monk) Lophius piscatorius A 67.831 Silvery pout . Gadiculus argentcus D 251.432 Whiting Merl.angws merl.angus D 355.633 Poor cod Trisopterus ininutus M 14.134 aib (Whiting pout) Trisopteruo luocuo R 1.935 Pollack Pollachius poZtachws M 11.936 Three-bearded rockling Gawopoarus vuZgaris R +37 .Fork beard . Phycis bZennoides R +38 Hake Merl.uccius merZuccius F 7.639 Pearlfish Echiodon dru.mondi R +40 Garfish BeZone beZone R 0.44J Sand-smelt Atherina presbyter R +42 Big-scale sand-smelt Atherina boyeri R +43 Dory Zcus faber R 0.144 Boar-fish .' Capros aper V +45 Snipefish Macroramphosus s(JoZo~ V +46 Greater pipefish Syngnat'kts acus R +47 Nilsson's pipefish Syngnathus roste ll.atus F +48 D~ep snouted pipefish Syngnat'kts typhZe ·R +49 Straight-nosed pipefish Nerophis ophidion R +50 Warm pipefish Nerophis Zwnbriciformis R +

Table 2 (continued)

Fish species Occur- Biomass*rence ('000 tannes)

51 Snake pipefish EnteZurus aequoreusI.R +

52 Seahorse Hippocampus ramuZosus V +53 Piper TrÜJZa Zyra R +54 Tub gurnard Tl"igl,a lucerna M 20.255 Red gurnard AspitrÜJZa cuculus R 1.956 Grcy gurnard EutrÜJl,a gurnardus D 639.257 Strcaked gurnard Trigl,oporus Zastoviza R +58 Bass DicentraI'cr.us Zabrax R .+59 Wreckfish Po Zyprion american:us V +60 Comber Serramts cabril,la V +61 Scad (Horse-mackerel) Trachurustrachurus D 223.262 Derbio Trachinotus ovatu.s V +63 Blac!, sca-bream SpondlJUOBOma cantharus R 0.264 Red sea-bream PageZZus bogaraveo R 0.265 Pandora Page Zlus erytJu:tin:us V +66 Spanish sca-bream PageZZus acarne V +67 Bogue Boops boops V· +68 Saupe Sca>pa sa Zpa V +69 Dentex Dente:c dente= V +70 Gilt-head Sparus aurata V +71 Meagre ArgyrosorrtUs regius V +72 Red mullet Mu'tZus surmuZetus R 0.273 Thick-lipped grey mullet Che Zoo Za'brosus F\ +74 Golden grey mullet Liza aurata R +75 Thin-lipped greymullet Liza ramada V +76 Cuckoo wrasse Labrua rrri:J; tus R +77 Ballan wrasse Labrus bergyZta R +78 Scale-rayed wrasse AcanthoZabrus paZtoni R +79 Rock cook Centro Zabms exo Zetus R +80 Goldsinny CtenoZabrus rupestris R +81 Corkwing wrasse CreniZabrus me tops R + •82 Greater weever Trachinu.s 'draao R +83 Lesser weever Echiichthys vipera M 26.484 Shanny Lipophrys phoZis V +85 Red band-Hsh CepoZa rübescens V +86 Smooth sandeel .Gymnarrmodytes semisquamatu8 M 42.087 Corbin's sandeel Hyperop Zus ·inmacuZatus' . F +88 Dragonet CaZZiooymus 7.yra . M 26.769 Spotted dragonet CaZZion:yrr..A.s 11UCUZatus R + .90 Reticulated dragonet . CaZZionymUG reticulat'..lG R +91 Black goby Gobius niger .' . F 6.092 Transparent goby Aphia minutel F +193 Crystal goby crystaZZogobius Zineari~ F +194 Two-spotted.goby Gcbiusculus fZavescens R +95 Common goby Pomatoschis'tua micropo F +196 Painted goby Pomatosahistus pia~~8 R +97 Sand goby Panatcsahistus mirrutUs F 6.098 Norwny goby Pcmatosaht.stua n01"'1Jegicus R +99 Brill Scophtha?mus rhorrJ:Ju8 . F 6.0

100 Turbot ScoplzthC.Zmus m::i:dmus. M 20.0

•

Table 2 (continued)

Fish species Occur- Biomass*rence ('000 tonnes)

101 Megrim102 Topknot103 Scaldfish104 Plaice105 ?Flounder106 Sand sole107 Sole108 Solenette109 Thickback sole110 Trigger fish

Lepidorhombus whiffiagonisZeugopt~s runctatusArnogZossus ZaternaPZeuroneates p~tessaPZatiahthys !ZesusPegusa ZasaarisSoZea soZeaBugZossidium ZuteumMwrochirus variegatusBaZistes aaroZinensis

I,

ARRDF?VARRV

52.8+0.4

530.28.0+.

51.41.5++

e Total 110 species

*Mean of the biomass on I January in 1977 and 1978.tContributions from minorspecies (+) ignored •

•

3561.7t

..Table 3 Atlantic fish species recorded and their abundance in the North Sea.

Key:D = Dominant, A ='Abundant, M = Moderately abundant,F = Frequent, R = Rare, V = Vagrant, + = less than 0.1 orbeing ignored

Fish species Occur- Biomass*'rence ('000 tonnes)

1 Hagfish2 Six-gilled shark3 Porbeagle.4 Hako5 Basking ~hark

6 Thresher7 Blue shark8· Smooth hammerheäd9 Spurdog

10 Velvet belly11 Darkie Charlie12 Rat-fish13 Eel14 Pearl-side15 Salmon16 Hatchet-fish17 Blue whiting18 Hollowsnout rat-tail19 Roundhead rat-tail20 Atiantic flying-fish21 Skipper22 Beryx23 Opah24 Oar-fish25 Deal-fish26 Blue-mouth27 Pilot-fish28 Ray' s bream29 Rough pomfret30 Long-finned bream31 Silver pomfret32 Black scabbard-fish33 Scabbard fish34 Frigate mackerei35 Mackerel36 Blue-fin tuna37 Long-fin tunny38 Little tunny39 Skipjack tuna40 Plain bonito41 Benito42 Louvar43 Swordfish44 Blackfish45 Cornish blackfish46 Sunfish47 Truncated sunfish48 Puffer-fish

Total 48 species

MYxine.gZutinosa FHemnchus griseus VLemma MsUS RIsu.rus oxyrinchus VCetorhinus m::z:x:imus RAZopias vuZpinus VPrionace gZauca· VSphyrtna zygaena' VSquaZus acanthias AEtmopterus spina:r: RDatatias Zicha RChimae~ monstrosa RAnguiZZa anguiZZa FMauroZicus mueZZeri RSa Zmo sa Zar FArgyropeZecus oZfersi RMiCramesistius poutassou MCoeZorinchus caeZorhincus RCoryphaenoides rupestris RCheiZopogon heterurus VScanberesox Saul'US VBeryx decadactyZus VLampris guttatus .VR~aZecus gZesne VTrachipterus arcticus VHeZicoZenus dactyZopterus RNciucrates ductor VBram:z brama M?Taractes asper .VTaractiChthys Zongipinnis Vpterycombus brama VAphanopus carbo VLepidopus caudatus VAuxis thazard VScomber scombrus DThunnus thynnus RThunnus ataZunga VEuthynnu s aUettaratus VEuthynnus pe Zamis VOrcynopsis uniCoZor VSarda sarda VLuvarus imperiaHs VXiphias gZadius VCentroZophus niger VSchedophitus medusophagus VMoZa moZa VRanzania Zaevia vLagocepha tua Zagocepha Zus V

5.1++' .'+++++

113.1. 0.9 .'+0.13.9+

'3.6+

154.2++++++++++

15.4.++++++

637.6.1.7++++++++++++

935.6t·

.e

•

*Mean of the biomass on 1 January in 1977 and 1978.tContributions from minor species (+) ignored.

..•

•Table 4 Comparison of indices for judging dominant fish

fauna in the North Sea

Fish species Individual species Biomass*

Boreal

Lusitanian

Atlantic

Number of

species

66

110

48

%

29.5

49.1

21.4

'000 tonnes

5237.9

3561. 7

935.6

%

53.8

36.6

9.6

* Mean of the biomass on 1 January in 1977 and 1978

Contributions from minor species ignored