Foods Utilized by Bowhead Whales NearBarter Island, Alaska, Autumn 1979

LLOYD F. LOWRY and JOHN J. BURNS

Introduction

Bowhead whales, Salaena mystice­tus, spend the late spring, summer, andearly autumn in the Beaufort Sea (Ser­geant and Hoek, 1974). On their north­ward spring migration they usuallybegin to pass Point Barrow, Alaska, inthe latter part of April (Durham, 1979;Braham and Krogman l

; Marquette2).

Their penetration of the spring ice sheetfrom the central Bering Sea is as muchas 3,000 km (Tomilin, 1957). DuringSeptember and October they again passPoint Barrow on their way into theChukchi Sea, some at least havingmoved westward along the Alaskancoast (Braham and Krogman, footnoteI). The latest sighting of a bowheadnear Point Barrow in the autumn, ofwhich we are aware, was of one seen on14 November 1977 (Burns, pel's. obs.).

The Beaufort Sea is a region of greatseasonal extremes. A cover of ice andsnow largely prevents photosynthet­ic primary production for at least 4months of the year. A brief period ofopen water occurs each summer, theduration and geographical extent ofwhich vary greatly from year to year. Inspite of such conditions, which wouldappear not to favor regular productionof large plankton stocks, several spe­cies of animals, including the bowheadwhale, use the Beaufort Sea as a sum­mer-early autumn feeding area.

'Braham, H., and B. D. Krogman. 1977. Popula­tion biology of the bowhead (Sa/aena mysticetus)and beluga (De/phinapterus /eucas) whale in theBering, Chukchi, and Beaufort Seas. Processedrep., 29 p. Natl. Mar. Mammal Lab., Natl. Mar.Fish. Serv., NOAA, 7600 Sand Point Way N.E.,Bldg. 32, Seattle, WA 98115.2Marquette, W. M. 1977 The 1976 catch ofbowhead whales (Sa/aena mysticetus) by Alas­kan Eskimos, with a review of the fishery, 1973­76, and a biological summary of the species.Processed rep., 80 p. atl. Mar. Mammal Lab ..Natl. Mar. Fish. Serv., NOAA, 7600 Sand PointWay N.E., Bldg. 32, Seattle, WA 98115.

88

It is not known whether bowheadsfeed during winter while they are in theBering Sea. They feed only little or notat all during their spring migration(Johnson et aI., 1966; Marquette, foot­note 2; Foote3 ). Intensive feeding oc­curs during summer and autumn in theeastern Arctic (Scoresby, 1820) and in­deed in Alaskan waters the only whalestomachs which contained appreciableamounts of food have been taken dur­ing the autumn whaling season (Lowryet aI., 1978). Large aggregations ofbowheads, which appeared to be feed­ing, have been seen nearshore east ofPoint Barrow in September (Brahamand Krogman, footnote I; Burns, pel's.obs.). Intensive feeding presumablyoccurs while the whales are in theBeaufort Sea. The quantities and kindsof available food in this region must beadequate to meet immediate bioener­getic requirements of whales and toprovide reserves for periods of reducedfeeding.

There are no published accounts ofwhat foods are utilized by bowheads inthe Beaufort Sea east of Point Barrow.We have recently acquired and ex­amined samples of stomach contentsfrom fi ve of these animals taken be­tween 20 September and 11 October1979 near Barter Island, Alaska.

Methods

In the field, samples ranging involume from about 200 to 2,500 mlwere randomly collected from thewhales' stomachs. From the whaledesignated as 79-KK -5, an additionalnonrandom sample was taken whichincluded primarily large, unusual ap­pearing items. With the exception of

3Foote, D. C. 1964. Observations of the bowheadwhale at Point Hope, Alaska. Unpubl. manuscr.,78 p. Geogr. Dep .. McGill Univ., Montreal,Que.. Can.

Lloyd F. Lowry and John J. Burns are with theAlaska Department of Fish and Game, 1300 Col­lege Road, Fairbanks, AK 99701.

whale 79-KK-I, which was recovered 2days after it was struck, samples werecollected within a few hours of the timethe whale was killed and landed. Sampleswere labeled, preserved in a 10 percentFormalin4 solution, and delivered to Fair­banks, Alaska.

In the laboratory, a 100 ml aliquot ofeach sample was taken for possiblefuture fatty acid content analysis. Theremainder of the samples were drainedand gently washed on a 1.00 mm meshsieve. The stomach contents were thensorted macroscopically into major tax­onomic groups, and the volume of eachgroup was determined. The items ineach group were examined microscop­ically when necessary and identified tospecies if possible. The number ofindividuals and total volume of eachprey species were determined and thelengths of representative specimenswere measured. In the case of abun­dant, small organisms such as cope­pods. the volume and number of thevarious species were estimated fromsubsamples.

Results

Based on the quantities and condi­tion of the stomach contents, all fivewhales were feeding at the time theywere killed. Estimated total volume ofstomach contents varied from 19 to 45 I(5-12 gallons). A summary of the spe­cies present, approximate abundance ineach sample, and those previously re­ported as food items in whales taken offnorthern Alaska are presented in Table1. Copepods were found in all fivesamples and were the dominant fooditem in three. Calanus hyperboreuswas by far the most commonly eatenspecies. The stomach contents of whale79-KK-4 were in particularly goodcondition. In that whale most of the C.hyperboreus eaten were copepod idStage Y. Euphausiids, almost exclu-

"Reference to trade names or commercial firmsdoes not imply endorsement by the NationalMarine Fisheries Service, NOAA.

Marine Fisheries Review

Table 1.-Food items from bowhead whale stomach samples collected at Kaktovik, Barter Island, Alaska, September-October 1979.

Whale specimen number Whale specimen number

Food item 79·KK-l 79-KK-2 79-KK-3 79-KK·4 79-KK-5 Food item 79-KK-l 79-KK-2 79-KK-3 79-KK-4 79-KK-5

Copepods Monoculoides c.f. M. schneider; X XCalanus finmarchicus XX Munnopsis c.t. M. typica XCalanus hyperboreus XXX XXX XX XXX XX Onisimus glacialis XChiridius obtusifrons XX Onisimus Jiloralis -XHeterorhabdus sp. XX XX Rozinante fragifis 1 XMetridia lucens XX XX Weyprechtia heulgini X

Family Lysianassidae XEuphausiids

Thysanoessa raschii' XX XXX XX XXX ShrimpsThysanoessa inermis X Euafus gaimardii X

Sabinea septemcarinata XMysids Family Crangonidae X

Mysis litora/is XX XX XX Unidentified X

Hyperiid amphipods IsopodsHyperia medusarum X Saduria entomon XHyperia sp. XParathemisto abyssorum 1 XXParathemisto libel/ula I X X X X Cumaceans

Oiastylis sp. X

Gammarid amphipodsAcanthostepheia behringiensis' X FishesAcanthostepheia incarinata X Boreogadus saida XApherusa glacialis X Myoxocephalus quadricornis XAtyJus carinatus X X Pungitius pungitiusGammaracanthus loricatus X Unidentified XGammarus Sp.1 X

Pebbles X X

XXX = dominant item in sample.XX = more than 10 individuals in sample.X = 1·10 individuals in sample .. = present in qualitative sample only.'Indicates previously reported food items of bowhead whales from northern Alaska (Lowry et al .. 1978; Marquette. 1979).

1The overall mean percent of contents was calculated based on the volume and percent composition of each sample and theestimated total contents of stomachs from which the samples were taken.

Table 2.-Quanlitative composition of stomach contents from bowhead whales collected at Kaktovik, autumn 1979.For each whale, numbers indicate percent of the sample volume comprised of each prey type.

Whale specimen number Overall meanpercent of

Prey type 79-KK-l 79-KK·2 79-KK-3 79-KK-4 79-KK-5 contents1

Copepod 99.7 99.0 23.4 88.3 <0.1 598Euphausiid 0.3 67.8 4.9 97.9 37.2Mysid 0.3 7.0 0.8 0.2Hyperiid amphipod <0.1 0.1 0.5 0.4 0.1Gammarid amphipod 0.1 0.1 0.3 2.4 01 0.4Other invertebrate <0.1 ,'_0.1 2.3 1.1 0.6Fish <0.1 0.1 1.0 1.7 0.4Sample volume (ml) 2,406.2 545.2 399.7 131.3 357.9Estimated total volumeof contents (gallons) 12 6 5 10

sively Thysanoessa raschii, occurredin four samples and were dominant intwo. Mysis litoralis was common inthree samples. Although at least 22other prey species were identified,none were major components of thefood. The majority of identified specieswere amphipods, most of which arebenthic forms.

A quantitative summary of the majorprey types found in the samples isshown in Table 2. In addition to theproportion of each sample which wascomprised of each prey type, an overallmean percentage of contents was calcu­lated for each prey type based on thevolume of subsamples, the proportionof prey types in the subsamples, and theestimated total contents of each stom­ach. Copepods and euphausiids in com­bination made up 91.2-99.7 percent ofthe contents of all subsamples. Therelative importance of these two preytypes varied markedly from over 99percent copepods in whales 79-KK-Iand 79-KK -2, to almost 98 percenteuphausiids in 79-KK-5. In the overallcomposition of the food, cope podswere more important in terms of vol-

Sept.-Oct. 1980

ume than were euphausiids. All otherfood types were insignificant in termsof overall volume consumed.

Discussion

The samples of stomach contents justdescribed constitute the only data avail­able on bowhead whale foods in theeastern portion of the Alaskan BeaufortSea. Two whales taken at Barrow inSeptember 1976 had eaten mostly eu­phausi ids (Lowry et aI., 1978). Theprincipal euphausiid species (Thysa-

noessa raschii) found in whales takenat Kaktovik was the same as that foundin the whales taken at Barrow. Thisspecies is widely distributed in Arcticwaters (Geiger et aI., 1968) and is ofgreatest abundance in the nearshoreneritic zone (Nemoto, 1966). A whaletaken at Barrow in May 1977 had eatenmainly copepods (Marquette, 1979).None of the copepod species eaten atKaktovik were found in the whale takenat Barrow. This is particularly interest­ing since the main species eaten at

89

Figure I -Diagrammatic representation of major trophic connections in the pelagicfood web of the western Beaufort Sea.

bowheads ----..

phytoplankton ~e:::.:::'~d~J/ ?'WC cod~ ',"ged seal, ~meroplankton -------7- !/ belukhas humans

bacteria hyperl;d amph,pods ~ /

myslds \ ~detritus r.mged seals ~ polar bears ]

~<lrctlc foxes

birds -------=- ~

Barrow (Calanus glacialis and Me­tridia longa) and Kaktovik (Calanushyperboreus) are all considered to bewidely distributed in surface waters ofthe Arctic Ocean (Grainger, 1965). It isprobable that copepods and euphau­siids are, overall, the most importantbowhead foods in the Beaufort Sea.Mysids and hyperiid amphipods alsoare concentrated in some regions andmay be locally important foods.

A large number of prey species wereidentified from the Kaktovik whales.Mysids, isopods, and cumaceans werenot found among the Barrow speci­mens. The only previous indication thatfishes might be eaten by bowheads wasa fish scale in specimen 77-B-5 (Mar­quette, 1979). Fishes representingthree species were found in the whalestaken at Kaktovik. In addition, at least10 species of amphipods and 2 speciesof shrimp were first recorded as bow­head prey in these samples.

Although organisms such as gam­marid amphipods, fishes, and isopodsare apparently not major foods of bow­heads in terms of quantities consumed,their presence in the stomach contentsis of some significance. The presenceof pebbles and bottom dwelling speciesindicates that all the whales taken atKaktovik had fed at least partially nearthe sea floor. Pelagic prey far outnum­bered the benthic organisms. There­fore, a feeding dive probably involvesswimming obliquely from surface tobottom and back, feeding the entiretime. Saduria entomon has not beenfound deeper than 44 m in the BeaufortSea (McCrimmon and Bray, 1962).Myoxocephalus quadricornis and Pun­gitius pungitius are characteristic ofcoastal fresh and brackish water (An­driyashev, 1954; Walters, 1955). There­fore, at least whales 79-KK-3 and 79­KK-5 had fed in relatively shallow,nearshore waters.

Although exploration and develop­ment of Beaufort Sea hydrocarbonreserves are underway in Canadianwaters and imminent off Alaska, thepotential effects of such activities onfoods of bowhead whales and foodwebs of the Beaufort Sea are impossibleto predict at this time. The only majorbowhead prey species which has been

90

tested for hydrocarbon sensiti vity isCalanus hyperboreus. This specieswas found to be "surprisingly resistantto all of the oils tested" (Percy andMullin, 1975). Hydrocarbon sensitiv­ity data for other key species in theBeaufort Sea food web such as othercopepods; Arctic cod, Boreogadussaida; euphausiids; mysids; and hy­periid amphipods are urgently needed.

In the Alaskan Beaufort Sea, bow­heads depend primarily on a pelagicfood web (Fig. I). Arctic cod feedprimarily on copepods in offshore(greater than 40 m deep) waters duringsummer (Frost et a1. 5 ). During thesummer, ringed seals, Phoca hispida,feed mostly on euphausiids, hyperiidamphipods, and mysids (Lowry et a1. 6 ,

1978). Ringed seals and Arctic cod areprobably the most significant trophiccompetitors of bowhead whales inthe Beaufort Sea. Changes in popUla­tions of these competing species,whether natural or caused by AlaskaOuter Continental Shelf oil and gas

5Frost, K. J., L. E Lowry, and J. J. Burns. 1978.Offshore delrersal fishes and epibenthic inverte·brates of the northeastern Chukchi and westernBeaufort Seas. Appendix to: Trophic relation­ships among ice inhabiting phocid seals. AnnuRep. RU 232, 39 p. U.S. Dep. Cammer., Natl.Oceanic Almas. Admin., Outer Continental ShelfEnvironmental Assessment Program, Boulder,Colo.6Lowry, L. E, K. J. Frost. and J. J. Burns. 1979.Trophic relationships among ice-inhabiting pho­cid seals. Final Rep. Beaufort Sea Activities, RU232,55 p. U.S. Dep. Commer., Natl. OceanicAlmos. Admin .• Outer Continental Shelf En­vironmental Assessment Program. Boulder,Colo.

development activities, may affect thesize and recovery rate of the bowheadpopulation.

Acknowledgments

This study was part of ProjectWhales (Research Uni t 280), com­pleted by the Naval Arctic ResearchLaboratory, Barrow, Alaska. ProjectWhales was funded by the U.S. Bureauof Land Management/Outer Conti­nental Shelf studies. T. Albert, Univer­sity of Maryland, coordinated the ac­quisition of specimens and undertookfield work to acquire some of them. G.Jarrell, M. Nerini, and D. Smullin,with the National Marine FisheriesService, Seattle, Wash., also providedassistance -Jarrell and Smullin by ob­taining some specimens at Barter Islandand Nerini by transporting and makingthem available to us. Laboratory fa­cilities were provided by the AlaskaDepartment of Fish and Game, Fair­banks. We are indebted to G. Mueller,A. Adams, and K. Coyle, University ofAlaska, Institute of Marine Sciences,for identification of copepods and am­phipods. K. Frost, Alaska Departmentof Fish and Game, Fairbanks, providedinvaluable assistance in all phases ofthis study. Our thanks are also extendedto those whaling captains and crewsat Barter Island who cooperated inthis effort.

Literature CitedAndriyashev, A. P. 1954. Ryby severnykh

morei SSSR (Fishes of the northern seas of the

Marine Fisheries Review

U.S.S.R.). Acad. Nauk SSSR, Opredelitelipo Faune SSSR 53, 566 p. Izd. Akad. NaukSSSR, Moscow-Leningrad. (Translated by Isr.Program Sci. Transl., 1964,617 p.; avail. U.S.Dep. Commer., Natl. Tech. Inf. Serv.,Springfield, Va., as OTS63-11160.)

Durham, F E. 1979. The catch of bow­head whales (Ba/aena mysticetlls) by Eski­mos' with emphasis on the western Arctic.Nat. His!. Mus. Los Ang. Cty., Contrib. Sci.314,14 p.

Geiger, S. R., K. Rodriguez, and M. M. Murillo.1968. Euphausiacea of the Arctic Ocean andits peripheral seas. Bull. South. Calif. Acad.Sci. 67:69-79.

Grainger, E. H. 1965. Zooplankton from theArctic Ocean and adjacent Canadian waters.J. Fish. Res. Board Can. 22:543-564.

Johnson, M. L., C. H. Fiscus, B. T. Ostenson,and M. L. Barbour. 1966. Marine mam­mals. InN. J. Wilimovsky and J. N. Wol fe(editors), Environment of the Cape Thompson

region, Alaska, p. 877-924. U.S. A. E c.,Oak Ridge, Tenn.

Lowry, L. F, K. 1. Frost, andJ. J. Burns. 1978.Food of ringed seals and bowhead whales nearPoint Barrow, Alaska. Can. Field-Nat. 92:67-70.

Marquette, W. M. 1979. The 1977 catch ofbowhead whales (Ba/aena mysticetlls) byAlaskan Eskimos. Rep. Int. Whaling Comm.29:28 I-289.

McCrimmon, H., and J. Bray. 1962. Obser­vations on the isopod Mesidotea entomon inthe western Canadian Arctic Ocean. J. Fish.Res. Board Can. 19:489-496.

Nemoto, T. 1966. Thysanoessa euphausiids,comparative morphology, allomorphosis andecology. Sci. Rep. Whales Res. Inst. 20:109-155.

Percy, 1. A., and T. C. Mullin. 1975. Effectsof crude oils on arctic marine invertebrates.Beaufort Sea Project Tech. Rep. II, 167 p.Dep. Environ., Victoria, B.C.

Scoresby, W., Jr. 1820. An account of theArctic regions, with a history and descriptionof the northern whale-fishery. Vol. 2. Archi­bald Constable and Co., Edinburgh, 574 p.

Sergeant, D. E., and W. Hoek. 1974. Sea­sonal distribution of bowhead and whitewhales in the eastern Beaufort Sea. In J. C.Reed and J. E. Sater (editors), The coast andshelf of the Beaufort Sea, p. 705-719. ArcticInst. North Am., Arlington, Va.

Tomilin, A. G. 1957. Zveri SSSR i prile­zhashchikh stran (Mammals of the U.S.S.R.and adjacent countries). Vol. 9. Kitoobraznye(Cetaceans). Izd. Akad. Nauk SSSR, Mos­cow, 756 p. [In Russ.] (Translated by lsI.Program Sci. Trans!., 1967,717 p.; avail. U.S.Dep. Com mer. , Natl. Tech. Inf. Serv.,Springfield, Va., as TT 65-50086.)

Walters, V. 1955. Fishes of westernArctic America and eastern Arctic Siberia,taxonomy and zoogeography. Bull. Am.Mus. Nat. Hist. 106:259-368.

Table 1.-Amino acid content of urine from a bowheadwhale.

Some Observations on UrineFrom a Bowhead Whale

also occasional oxalate crystals as wellas a few triple phosphate crystals.

On further analysis the following re­sults were obtained: Sodium ion 183meq/I, potassium ion 14.4 meq/I,chloride ion 433 meq/I, osmolality1,440 milliosmols/I, creatinine 400mg/dl, urea N 3,000 mg/dl. The aminoacid pattern obtained can be seen inTable I and is similar to that seen inadult mammals such as the dog, The

W. MEDWAY

The analysis of urine is an essentialpart of any examination of an animal todetermine its health status. This is trueespecially when (for purposes of com­parison) there is a large store of dataabout urine of the species in question.The urine of the bowhead whale,Balaena mysticetus, has apparently notbeen examined.

On 18 May 1978 a urine sample iden­tified as having originated from abowhead whale, designated by the Na­tional Marine Fisheries Service as#78B2, was presented to this labora­tory. The urine was obtained by cys­tocentesis from a male about 8.4 m inlength, taken by Eskimo hunters on 2May 1978 at Barrow, Alaska. The urinewas refrigerated until 6 May, then fro­zen. On 15 May the frozen specimenwas prepared for shipment. Unforeseen

W. Medway is Chief. Section of ClinicalLaboratory Medicine, School of VeterinaryMedicine, University of Pennsylvania, Philadel­phia, PA 19104.

delays during shipment allowed theurine to thaw by the time it reached thislaboratory. Findings are presented herenot only for general information butalso as a small contribution to the dataconcerned with the biology of this en­dangered species.

Results and Discussion

On routine clinical urinalysis the fol­lowing observations were made. Theurine was dark amber, clear, and had noodor. The pH was 5.5, and the specificgravity (SG) was 1.032; there was atrace of protein; and the tests forketones, glucose, reducing substances,bile pigments, hemoglobin, andurobilinogen were negative_ Micro­scopic examination of the sediment re­vealed a few red and white cells, but nocasts; however, there were myriads ofepithelial cells (some were cornified),and there were some bladder transi­tional cells and caudate cells. Therewere many unidentified spheroid crys­tals (probably urates), and there were

Amino acid

ThreonineSerineAsparagineGlutamineProlineGlutamic acidGlycineAlanineex Aminoadipic acida Amino-n-butyric acidValineHalf cystineCystathionineMethionineIsoleucineLeucineTyrosinePhenylalanineOrnithineLysine1-MethylhistidineHistidine3-MethylhistidineArginineTrimethyllysineNN dimethylarginineN'N dimethylarginine

Nanomoles/mgcreatinine

312899326411844314.51718

1152510

Trace182910

Trace17

Trace16

TraceTrace204

3124

Sept.-Ocr. 1980 91