,
,
to
This paper not
be cited without prior reference to the aüthofs
C.M. 1996/N: 3
Marine MaiririiaIs Committee
the Exploration ofthe Sea . .'"
I b 11 ot h eh
'Interri~tional Cot.ulcil for ~i:r:"k~;l:":J!':(
nEvELOPMENT OF STANDAiIDIZED SAMFLING
METHOnS FORUSE IN REGULAR nIET STUDIES OF
NORTHEAST ATLANTIC MINKE WHALES
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BALAENOPTERA ACUTOROSTRAT.A
•
I
•
TORE BAUG, ULF LINDSTRßM & KJELL T. NILSSEN
Noiwegiari institute ofFisheries arid Aqüacultüre, P.O.Box 251 i, N-9002 Tromsß, Noiway
ABSTRACT
Impiementation ofpredator-prey interactions in multispecies models reqüires regidciriy updated
wormation about stomach contents of individual top predators. Miilke whales Balaenoptera
acutorostrata are now included iii the multispecies modet1irig of the Barents Sea resources.
This hiiS aCtlll1llzed development of an effective and feasible method desi~1(~d to provide
regular aiid representative irifonnation about stomach contents from the species. It is assumed
that this may be obt8.ined most conveniently by collection of data froin commerciaJ. catches.
H6wever, it was ackrlowledged thai the comprehensive arid tiffie- arid. resource-oonsuming
II1E~thods used in recent Norwegian scientific catch operations where the diet studies were
based on total forestomach coriümts (väryißg from i to 150 I) from eäch .whale, had to be
simplified considerably. Experiments designed to achieve this were .st3rted on a pilot seate
dtiring scientific whaling in 1994, and 'continued more ,comprehensively durlng commercial
whating in 1995. Thc results iridicate that such sinip1ification is possible. Under
ässumptions, randomized collection of rehitively smäII (2-3 I) subsampies laken direetly froin
the opened forestomach appears io be sufficient for an adequate and representative description
of minke whale diets. The 1995 nunke whale diets, as observed on 6 vessels participating in the
commercial ~tches,was. cllaräCtenzed by
äIffiost total dominance. of krill Thysanoessa. sp.
iri the northem Bärents Sea (mchiding areas west of Spiisbergen). The southem Barents Sea
areä was charactenzed by a more ßUxed minke. whale diet which contarned kri11 and herring
Clupea harengus mcomparable amounts, but wso corisiderable amounts of capelin Mal/alus
vi//osUs, cod Gadus morhUa äßd haddock Melanogrammus aeglefinus.
certam
an
1
r---------------
.
.
,
"
INTRODUCTION
In the managemerit cf fish stockS. a strategy far a gradual implementation of a multispecies
approach is currentiy being mvestigated: The madelling effort for resoufces in the Barents Sea
has yielded an area-sti'uctured multispecies modei. MuLTSPEC. where particuiar emphasis is
placed on the stocks of key fish species; capelin Mal/otus
villosUs. herrirlg Clupea harengus
. .
,"
e
M
and eod
Gadus
morhua. (Ulltang 1995). Although these fish stock~ eoristitUte the core of the
.
.
model,' Ulltahg (loc.cit.) emphasizes that the inciusiciri of manne mariuria1s is essential iri
multispecies models for the Barents Sea. Tbe current main purpose for including thc tWo m~st
numerous marine mamniai spedes in the area.
haip
seats Phoca groenlandica and minke
whales Balaenoptera acutorostrata. üi the model is to try i~ detennirie what data is necessarY
to predi~t the effects afthese two species' predation on the stocks cf capelin, herring arid cad.
1'0 ~ more limited eXtcnt. it is roso attempterl to irivestlgate. through simulation studies. likely
. lorig~i~rin effects
of different exploitation strategies on the fish äiid mammals stocks on the
ecosystem.
amanagement eciriteXt has so far been to quantify tbe ecideapeiin interactions. more specific~ly to eStimäte the im~ciation mortaIities of mature capelin
Tbe main use cf MuiTSPEC in
generated
,"
by
..
',
eod (Ulltang 1995). Additiofially. Bogstad et al. (1996) have desCrlbed
_.
.',
" "
"".
",:.,'
,",',
""",
."
,
MULTSPEC as a simulation model where herring is included and ",here the sensitiVity of the
model to aSsumptions of food preferenees cind stock sizes cf ~e wh3.1es anrl harp seals are
exi>lored.
.The development of mwtlspecies modeis has given tbe analysis cf thc feedirig ecology of
Tlic noith~t Atlanti~ stock' of minke' whaIes is
boreo-arctic. With migi-ations to feeding äi~ iri the far north in spririg '3.ndearly summer. arid
.important top predators particular actUality.
southwards to breeding areas in the autumn (Jonsgard 1966). In order to evaluate the
2
-
"
ecologiciat significance of this stock, a scientific whafulg program, 'addressing paiticulärly
questioiis conceming feeding ecölogy
by using stornach analyses arid coneurrent estlmates of
im~y av8ilabiliiy, was conducted by Norway in i992-1994 (Haug et a/. 1995a,b, 1996a, Skaug
et al. 1996). When choosing food preference parameters for nUnke whales m the MULTSPEc
model, results from the 1992-1994 diet 'studies were used for setting the ilicely ranges of the
parameter values (Bogstad et 0/. 1996)..
The eStimation part of the MULTSPEC prograIn requires updated irifonnation from anriual
field samplings targeted especiaily towai-rls stornach content data (ai present only from the
'predator cod). Userl as
asimulation model, however, the rieed of'ariri~auy' updated stoin~ch
cont(mt dat~ is not equaIiy critical. On a longer tenn, however, it is desirable also to mchide
interactions other than the cod-capelin interaction in
program. This
\viiI
tbe. estiniatiori part cf the MoLTSPEC
require regularly updated mforination about sio~ach contents of other
incltided top predators such as minke whales. It will be particularly iinportarit to have claia
desenbillg the whaie diets under different
~cologicat sitüations, arid .to identity whai happens
when changes occur.
Sdentitic whaIing operations are eXtensive and exPensive arid unllkely to be camed out
routiIiely. Thus, in order to provide regUlar data on ininke whwe feedmg ecology, a simpler
solution has to be sought. The most convenient way to obtäiri such datll is probably by
colIeCtiön
•
cf aclequate material froßt minke whales taken in coirimerciai catches. Thc methods
used dunng the scieriimc whaling operations were based on the examinatiori of the toial
forestomach contents (rariging in volume from less thari 1 I to more thän 150 I) in each whale,
and were, therefore, eXtremely time- aiid resource-constiming (see Ha~g er al.1995a; i996a, b,
Lindstrorn
et al.
1996). Routirie sarnpling from cömrnerciat eatches Will, then~fore, require
an
substaniiai siIDplificaiions. The developmeni of etfective and feasible method which gives
.
representative stornach content .data duringcoinme~cial riünke whalirig ope~ationS. was thc
mam purpose of the invesiigaiions reported here.
Some, pilot SampIes were taken during
sdentific whalirig operations iri 1994, whereas the major sampling took place durmg the 1995
commercial whaIirig season.
3
~
..
,~
MATERIAL AND MEmODS
Sampling 0/ whales
·ln
1993~ the Internatiorial Whalirig Conumssion (IWC) deCided that the so-called "small areas"
boundaries should be rctamed for thc management of Northeast Athintic minke whales.
According to this division, minke whales from thc Noi'th Sea (EN), cOaStal areas of Lofoten
ancl Vester!Ien <BC), coas( ~f Finrimark arid the Barcnts Seä (EB), and
Spitsöergen waters (ES)
Bear
Islarid arid
are corisidered to beiong to different brecding stockS (seeFig 1),
althougb there was cvidencc of exchange arriong some of thc areas, in parti6l.11ai"(Aßon. 1993). Durlrig co~ercial catch operations, quotas are set per small
EB-E8-EN
ärea,
and each
one 01- tWo of the designated small
areas meach season. Iri 1995, stornach sarnples were collected from ",hales caugltt by three
operatirig vessel is ailocaü~d a pariiculär boat quota in
vessels operating in area EB, two vessels opearting in area ES arid orie vessei with separate
·quotas in both these areas. Adequate sarnples were obtained frorii 37 minke whales (18 iri ~ea
EB, 19 iri area ES, see Fig. 1). In thc methodological arialyses, stomach sarnples from 16
minke whales taken in the 1994 scientific whaling operatio~ (3 from BC, 6 from EB arid
"1
from E~) wcre also included (see Haug et al. 1996a).
Whaies taken dUrlrig the 1994 scientifi6 whaling ·operations (6 July - 6 September) were
sampied raridorßIy on chärterecl
wfuwng vessels using
along predeterniined transects "(Haug ei
procedtires which included searching
ai. 1996a). Thc whales taken in the 1995 corrirrierdai
whaling operations were siirriplcd opportunisticallY in areas With expected high densities of
whales (Clmstensen &. 0ieri 1990) duririg thc period 13 May - 11 June.
Analyses and reconstruction 0/minke whale stomach contents
Tbe complete digestive tract was t3.ken out of the whale as soon as possibie (i-3 hours post
"IOrtern).
Minke whale stomaehs consist of aseries of four chiimbers (Olsen et aI.
1994), but
Lindstroin et ai. (1996) have shoWn that sampÜng and analyses of cOllterits from the flfst
chamber (the forestomach) is sufficient to describe
Iniitke whale diet. Thiis, onty
forestoniach contents were used in these anatyses. The onboard and iaboratory treatment ofthe
full forestomach contents are as descrlbed i~ detail by Haug et ai. (1995a, 1996a).
thc
4
In addition to the ordinarjr forestomach sampIes taken io estimate the iotal coritent (TS),
smalIer sub-samples (SS) of 2-3 i (after liqUid bad been filtered off) were colleeted from 43
forestomachs in 1994 arid 1995. Iri cases where tbe forestorriachs contained undigesierl, iarge
6sh (such as gadoids), these were reriioved, cotinied arid measun~rl onboard, after which the
remamirig arid more digested contents, if present, were subsampled. In allother cases thc
,
,
subsarnples were taken raridoIn1y from thc iotal forestörnach contents. All subsarnples were
frozen onboard for tater laboratory treatment. The contents remainirig iri the forestomach after
subsampliitg was transferred to the tuh arid sieve system arid treated as descnbcd by H3.ug
,
,
.
'
et
ai.
(1995a, 1996a). Laboratory treatment of SubSampIes aIid remaining contents from thc
forestomachs were identical, arid iheir sum became the estimated total forestomach sarnple. .
iritaet specimens of fish were identificd according to gross morphologicat charäctenstics
(pethon 1985), whlle sagittal otoliths arid cnistaceans were i~entified io 10weSt possihle taxon
(Enkell.1980, Breihy 1985, Härkönen '1986). The total nUffiber of eaeh flsh species was
cciIciJlated by ädding the number of fTesh speCiniens, intact skulls and half the total number of
otollths. For large gadoids, such as eod, haddock and smthe, free otoliths were separated into
nght arid letl otoliths and divided iritö geometrie Classes (with 0.2 mm intervats) whereas
otolithS. preseri~ iri. skulls, were paired arid nieasim~d~ Fro~ otolith .len~h-fish len~h1mass
correlations and rändom sub-samples of.200 iiödigested otoliths (or as many äs possible) from
each fish species, the initial prey masse!; at the time of ingestion were eSiimäted.
When estimating th~ hiomass of clustaceans found iri the stomachs at thci time of ingestion,
meari iriclividual weights of digested Crusüiceans were recorded. These maSses were based on
weights of a knoWn riinnber of individt.i8J.s (usually 250-300) in subsämple. Usmg krioWri
mean masses of fresh crUstaceans (see Haug er al.• 1995a), thc orlginaI biomass of ihe
crUsiäceans eaten by the fitinke whales was crudely estiriiated.
a
e
"
. Several feeding indices are comrrioOly used in Stömach analyses oftöp predators (Hyslop 1980,
Pierce & Boyie 1991). in ihe 1992-1994 diet studies of the ininke whale, the prey was
qi.uintified tising frequene;y of occiuTence, arid maSs and riuinerlcal fiieticins of iridividual prey
categones (Haüg et al. 1995a, 1996a). No feedirig iIidex, however. gives a complete or fully
re8Iisii~ pictiire of dietary comjlOsition. The esiimated masses of individtiaI minke ",haIe
forestomach contents vary cönsiderably (0-250 kg, see lfuug cl al., 1996b) in response to the
vanous states of Satiation the whales were caüght at. By using the traditional numerleal arid
mass fraCtions of mdividual prey categones to describe the minke whale diet, forestomachs
coniainirig large amounts of food äre given exaggerated importanee coinpared to ihose
coritammg little food. This problem rriay be avoided, however, by
an alternative mass
. index, catculatecl by summansing ihe percentage of each prey species froin each mdividuat
usmg
5
.
whale and dividing this by the total summarised percentages of all prey specimens from all
whales. This index give each forestomach the same importance irrespective of the very variable
content mass.
In this paper, the 1995 diet data are presented as frequency of occurrence of each prey item
arid as percentage weight of each prey species (method A) using the alternative mass index:
n
LWtI
WL = --:,;t==l_ _
7
n
LLWtI
1=1 t=1
. where. Wti is the relative contribution of mass (%) by prey species i to the 'contents in
forestomach t and
D
e
is the number of forestomachs inc1uded in the investigation. To simplitY
the presentations and calculations, prey items were gfouped into the following
.
taxa (see Figs
. 2
and 3): ZOOPLANKTON [krill (Thysanoessa sp.), copepods (Ca/anus sp.) and amphipods
(Parathemisto sp.)], HERR;ING, CAPELIN, COD, ~:bOCK Me/an~grammus aeg/efinus,
PELAGIC FISH [sandeel (Ammodytes sp.) and saithe Po//achius virens] and VARIOUS
FISH. Thus, i = 7.
. When comparing the food composition in the total forestomach sampie (TS) with the subsampie (88), the mass index.method (method A) w3:s compared with the more traditional bulk
.biomass index method (method B):
Bi = (bi/bt) x 100
. where bi is the total mass of prey catego.ry i (i = 7), and bt is the total mass cf an prey
categories
RE8ULT8
The 1995 die!
A minimum of 12 different prey species were identified in the stomaehs ofthe minke whales
sampled during commercial whaling operations in 1995 (T~le 1). Herring and kri11 occurred in
most stomaehs in the southern coastal EB area where 11 prey species were observed. Only 4
6
•
.
,
prey speeies were observed in the more northem ES area where the oeeurrenee of kriu was
par..ieularlY conspicuous. Using aFisher's exact test, it was evident that minke whaies in the
riorthex:n ES area had eaten
(P<O.OS).
,
_._
_;
,,_..
krill significantly more frequeritly than whales in the south ~B)
:.',';.'
.'. .
:
'
:
.
-
.
•. • :
I
In terms of calcuhited fresh mass (Fig. 2), zooplankton (krill) and herring (30% and 24%,
respectively) eonstinited more ihan half of the prey biorriass in area EB, wbere also eapeIin
(19%), 'haddoek (14%) arid ead (13%) were observed in eonsiderable amounts. The prey
, biciinass in area ES was ehaiactenzed by an aIniost total dominance (nearly 100%) ofkrill.
subSampies vs. total sampIes 0/ contentsIrom/orestomacns
Corripansan cfsubsarnples (SS) witn total sampIes (T~h were made on the basis of pooled data
from forestomaehs sampled during scientifie (1994) arid eommerciai (1995) wha1irig
operatioris. Thc matC::~al reveals a dominanee in reeonstrueted prey biomass of zooplankton
änd bemng, with sinaller eontributions of eapelin, eod, naddoek iind pelagie fish (Fig. 3).
App~e~t1y, the use of thc reeommended method A (tbe pereentage mass index method)
. mStead of nietbod B (the more traditional bulk biorriass index methad) inereased the relative
importanee of zooplankton and eorresporidingly deerased thc irriportanee cf most fisb species.
More interestirigly, however, it appears that the use of methcd A gives more siriillar results
•
~
.
when eompanson is made between the SS and TS sampIes. For instanee, the cont~bution of
zooplclnkton arid nemng to thc total biomaSs was simitai- (54% and 25%, respectiveiy) when
methöd' A was applied to both tbe SS al1d TS data. Appiyirig method H, however, thc
corresponding numbers differed betWeen SS. and TS and were, respeetively, 32% arid 44% for
zooplankton arid 42% arid 28 % for herring. Pairwise eomparisons of thc relative iritportanee
of ail 7 prey taxa, aS ealeulated using method A, between SS and TS using a WJeoxon signed
test, revealed no sigiUflcant differences (all p>0.05).
..
.,
-.}.
DISCUSSION
The observed 1995lriinke whale diet was cbaracterlzed by arlominanee ofzoopiarikton, niainIy
iciill, in the noithem (ES)
arid offish in the soüthem (EH) area..
area
The proininent role of krin in the northem area resembles observationS made duririg seientific '
whaIing iri 1993 'and 1994 (Haug et al. 1995b, 1996a), and i~ corisisterit with tbe current status
of the Barents seil ecosystem whieh, sinee 1992, häs been eharacterized by relatively large
7
amoinits ofzooplankton and a very iow abimdance cfcapelln (Anon. 1996). Atthough krill häS
been shown to play an unporuini roie on the nunke whale diet in are~ ES
iri
previous yeärs
(ionsgard 195i, 1982, Nord")' & BliX 1992), it is kriöwn thai capellit, ifabundant in sumcient
amoimts, may also be
an irnportarit dietary constittierit there
(Jonsgärd 1951; Haug et al.
1995a).
The riüxed fish diet documented in the EB area resembles observatioris made during the spring
ind ~ummer in all years (1992-1994) of sCientific whalirig when also hei-ring and gadoids
charaCieriZed the minke whaie diets
iri the more southem parts of the Barenis Sea and coastal
areas cf North Norway cHaug et 01.
i 995a,b,
1996a). Tbe timing of thc 1995 sampling froni
commercial catches coincided with paris of holh the spring and summer sampling periods of
the 1992-1994 investiglltions. SUIIÜner predation of minke whales upon hemng has also beeri
observed in coastal areas ofNorth NOrWay in preVious yeai-s (ionsgärd 1951, i982, Lydersen
et al. 1991, Nord")' & nlix 1992)..
While kriit was scarce in the observed 1992-1994 diets of minke whales in thc southem cOaStal
it contnbllterl significantly to the EB area diet iri
Analyses of the data colleeted dllring the scientific whäimg operations clearly showed
areas ofthe Barents Sea änd North Norway,
1995.
that minke whale meals consisting of zooplanktori tended to be smaller thm those consisting of
herring", cod arid haddock (Haug
ct al.
1996b). Furthermore, it is evident thai the, use of
traditionaI numericäl arid mass fuiction of individual prey categorles iends to give. whale
forestomachs that contäin large ämollrits of food an exaggerated irriportance compared with
those containing little food. Use ofthe traeÜtioriaI diet indices when presenting the results from
the 1992-1994 scientillc whaling operations (Haug
et al.
i995a, 1996a) may, tberefore, have
cönirlbuted to an uriderrepresentation of zoopicinktori aS compared to fish species. Use of the
perceniage mass index (methöd A), gives each stomach the salne irnportance irrespeCtive of
stomach cciriterii inäss and elhninates the problem with prey specrnc variat~cins. CertairiIy, krill
is kIloWn to h3.ve beeri Unportant fciod for minke whales in area EB älso
in previous yearS
(Chclstensen 1972, i974, Nord")' &. Blix 1992).
A comparison of the forestomach total (TS) and sub (SS) sampIes using both method A and
the more traditionäl buik biorriass index (method B) shows how the irnporiance of fish
increases and zooplankton decreases when the latter method is used. Also, the use of method
B appears to result in Ccinsiderable differerices in prey irnportance between the subsampie and
total sarnple. whereaS method A gives siriülar results for the two s~ts of forestomach sampIes.
In summary, the: present study_ seems to indicate that the colleetiori of relatively small
forestomach subsampIes appears to be sufficierii for an adequate arid ~ep~e~eritative descnption
of the diet of minke whales. Forestomachs contäining undigesü~d large fish (such
8
aS gadoids)
•
will, however, need a somewhat different treatment, either through increasing the size of the
subsampIe or through the analyses of the unäigested portion (counted and measured) on the
shi~. Aprerequisite for the use of subsmpies is ihe application of the p~icentage weight index
(method A) when the irnportance ofthe different prey items is quantified.
ACKNOWLEDGEMENTS .
Sincere thanks are due to field assistants and crews onboard the whallng vessels Ann Brita,
BrmuJsholmboen, Nybrama, Rango, Reinebuen and Ulvos. I. Ahlquist did the data work
necessary to plot the catch position and small area bOlll'idaries on ihe map, G.L. Andersen and
L. LindbIom did most of the laboratory treatment of the whale stomach contents, and we thank
G. Vlkingsson and RT. Barrett for- useful review and linguistic improvement of the
mamiscript. The ecological studies of Northeast Ailantic minke whales are supported
economically by the Research Council ofNorway, projeci i08146111O.
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•
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9
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e
.. Haug, T., Lindstmm, U., Nilssen, K.T., Rmtingen, I. & Skaug, H.J. 1996a. Diet arid food
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10
•
I
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Nord"}', E.S. and Blix, AS. 1992. Diet ofminke whales in the nartheastem Atlantic. Rep. illt.
Whal. Commll 42: 393-398.
Olsen, M.A, Nord")', E.S., Blix, A.S. and Mathiesen, S.D. 1994. Functional anatomy ofthe
gastrointestinal system of north-eastem Atlantic minke whales (Balaelloptera
acutorostrata). J. Zoo/., Lond. 234: 55-74.
Pethon, P. 1985. Asehehougs storejiskebok. Aschehoug, H. and Company (Nygaard, W.) NS.
Pierce, GJ. and Boyle, P.R 1991. A review ofmethods far diet analysis in piscivorous marine
mammals. Oeeanogr. Mar. Biol. Allnu. Rev. 29: 409-486.
Skaug, H.J., Gjßsreter, H., Haug, T., Lindstmffi, U. & NJ1ssen, K.T. 1996. Do minke whales
Balaelloptera acutorostrata exhibit particular prey preferences? J. Northw. Atl. Fisk
Sei.: in press.
•
Ulltang, 0. 1995. Multispecies modelling and management with reference to the Institute of
Marine Research's multispecies model for the Barents Sea. Pp. 659-670 in: Blix, A.S.,
WalIße, L. & Ulltang, 0. (eds). Whales, seals,jish andman. Elsevier Science B.V.
11
\
Table 1. Frequency of occurrence of empty forestomachs
and species identified in forestornachs of minke whales
caught in two regions in the Northeast Atlantic in Maylune 1995. The two most important prey species are
shaded. N = number of stomachs examined.
PERCENTAGEOCCURRENCE
PREY lTEM
EB
ES
ON=19)
Empty stomachs
Crustaceans
Calanoida
Calanus spp.
Euphausiacea
Thysanoessa spp.
Meganyctiphanes norvegica
0
0
5.6
~I3
21.1
Pisces
Clupeidae
Clupea harengus
t~sg
Osmeridae
Mallotus villosus
26.3
Gadidae
15.8
Gadus morhua
Melanogrammus aeglefinus 31.6
Pollachius virens
5.3
Molva molva
5.3
Unid. gadoid remains
15.8
Scorpenidae
Sebastes sp.
5.3
Myctophidae
Benthosema glaciale
10.5
Ammodytidae
Ammodvtes sp.
5.3
Unidentified remains
ON=18)
31.6
12
5.6
•
SPITSBERGEN
o
I
BARENTS SEA
ES
Q
BEAR ISL.
•
o
•
EB
00
•
0
Fig.1.
Ecological studies of northeast Atlantic minke whales based on forestomach analyses: Catch
positions for minke whales taken in 1994 (scientific whaling, n = 16; open circles) and 1995
(commercial whaling, n = 37; filled circles) in catch areas EC, EB and ES (see text for
explanation).
13
N=19
N=18
100 . . - - - - ,
80
60
40
111 Zooplankton
IIIJ Herring
~ Capelin
ml Cod
lIIl Haddock
• Varioua fiah
20
o
L..-
_
ES
EB
AREA
•
Fig.2.
Ecologica1 studies of northeast Atlantic minke whales based on forestomach analyses: Relative
dietary importance of prey items, measured by method A (see text) applied to total
forestomachs sampies, in whales taken in commereial cateh operations in areas EB and ES in
1995.
14
........
":
.
100 , - - - - -
-~
e,
80
iLl
u
Z
~
60
~
0
~
::2
1004
40
D Zooplankton
ll!I H'erring
rza Capclin
~ Cod
on Haddoek
~ Pelasie fish
• Various fish
)4
~
~
~
20
0
1'8
1'8
SS
SS
SAMPLB
•
Fig.3.
Eeologic::a1 studies of northeast Atlantic rniDke whates based on forestomach aI1a1yses:
Comparison of dietary importanee öf prey items) measuroo by methods A and B (see text)
applied to tötal and sub sampIes of forestomach contents, in whates taken in scientific whaling
operations in 1994 and in commercial whallng operations in 1995.
IS