ARCTIC VOL. 43, NO. 2 (JUNE 1990) P. 127-128

Spring Sightings of Narwhal and Beluga Calves in Lancaster Sound, N.W.T. ~~ SUSAN E. COSENS' and LARRY P. DUECK'

(Received 24 May 1989; accepted in revisedforrn 11 October 1989)

ABSTRACT. During aerial surveys1986 in of whales migratingin Lancaster Sound, observedwe newborn narwhalsearly as as 27 May and regularly thereafter.Beluga calves were first seen on31 May and wereseen sporadically throughout the study period.These observationsrepresent the earliest reported sightings to dateof newborn narwhals. Key words: narwhal, beluga,calves

RÉSUMÉ. Au cours de relevés aériens effectués 1986 en sur desbaleines sedirigeant versle détroit de Lancaster, on aobservé des bébés narvals dès le 27 mai età intervalles réguliers parla suite. Les premières observations de bébés bélugasont étéfaites le31 mai et on a ensuite aperçuces animaux de façon sporadique durant toutela périoded'étude. Ces observationsreprésentent jusqu'à ce jour lesobservations les plus précoces de bébés narvals. Mots clés:narval, Mluga, petits Traduit pourle journal par NésidaLoyer.

INTRODUCTION about one-third adult body length (see Brodie, 1971; Mans- field et al., 1975). Early accounts describe the narwhal (Monodon monoceros) as Flights began at the mouth of Admiralty Inlet (73"45'N, having either a protracted breeding season (Tomilin, 1957)or 84'05'W) and generally proceeded east along the ice edge to no breeding season at all (Degerb~rland Freuchen, 1935; Navy Board Inlet,north several kilometres from the ice edge, Porsild, 1922; Vibe, 1950). More recently, Best and Fisher west to Cape Craufordor beyond, then east along the ice edge (1974) used the technique of backdating conception dates to the startpoint (Fig. 1). Surveys done prior to mid-June were (Brodie, 1971; Sergeant, 1973)and concluded that narwhals frequently hampered by 80-99% pack ice, so flight paths are seasonal breeders. Hay (1984) similarly concluded that diverged fromthe preferred course to follow openleads that narwhals breed seasonally, with conception occurring be- were available. tween 20 March and 19 Mayand calving occurring in July and August. RESULTS AND DISCUSSION Evidence suggests that belugas have a protracted calving period and that the peak calving period varies with locality We saw young narwhal or beluga calves on15 of 27 aerial (Braham, 1984; Kleinenberget al., 1964). Braham (1984)indi- surveys. Our first sighting of a young, presumably newborn, cates that newborn belugas have been sighted in the Cana- narwhal calf was on 27 May. Thereafter, we regularly saw dian Arctic between Marchand September. Sergeant (1973) young calves throughout the study period (Table 1). They estimated the peak calving period for western Hudson Bay werefrequently seen swimming alongside the tails of belugas to be late June. Cumberland Sound belugas appar- adult females and were occasionally seen nursing. Beluga ently breed in May and calve mainly in late July to early calves were first sighted on 31 Mayand irregularly thereafter August (Brodie, 1971). (Table 1). Sight and collection records of newborn narwhals and The irregularity with which wesaw newborn belugas may belugas usually date from June to August,a result of the time be related to icebreaker activity during our surveys. Of ten frame when most studies are conducted in the Arctic (see Ellis, 1957; Falliset al., 1983; Greendale and Brousseau-Green- Island 62 dale, 1976; Hay and McClung, 1976; Mansfield et al., 1975). Few observations of arctic whales have been made at other times of the year (see Porsild, 1922). In 1986,as part of a study of the effects of icebreaker activity on the behaviour and distribution of narwhals and belugas, we conducted aerial Lancaster surveys of migrating whales in Lancaster Sound from May to July. We report observations of newborn narwhalsand belu- Sound gas made duringthese early spring surveys.

METHODS We flew 27 surveys between 24 May and 6 July 1986, with twoto three observers in a Bell 206Jet Ranger helicopter at an altitude of about 230 m and a flight speed of about 160 km/h. We collected data on whales sighted within a

250 m strip oneither side of the helicopter, identifylng spe- FIG. I. Preferred flight path used during aerial surveys. Actual flight paths cies, sex, approximate age and ongoing activity. Newborns depended on the distributionof pack ice in LancasterSound. Hatched areas were identified by their slate gray colour and small size, represent land-fastice (after Cosens and Dueck, 1988).

'Department of Fisheries and Oceans, Central andArctic Region,501 University Crescent, Winnipeg, Manitoba,Canada R3T 2N6 OThe Arctic Insitute of North America 128 / S.E. COSENS and L.P. DUECK

TABLE 1. Numbers of young narwhaland beluga calves seenduring ACKNOWLEDGEMENTS aerial surveys in1986" The study was supportedby funds from the Northern Oiland Gas Number of neonates sighted Action Program (NOGAP). The Polar Continental Shelf Project survey NarwhalDate of survey Beluga (Resolute Bay,N.W.T.) provided additional, much needed field support. Glenn Williams,the G.N.W.T. Natural Resources Officerin 27 May' 27 1 (6) - Arctic Bay, N.W.T.,provided helpful adviceand generously donated 28 May 3 (7) 0 storage space. Ipilee Koonoo, Timothy Sagoyak, Val Churney and 31 May 31 0 2 (6) Dave Yablecki assistedwith datacollection and campmaintenance. 1 June 4 (8) 0 4 Juneb,. 4 1 (4) - We thankour helicopter pilots for their patience and capable flying. 8 June. 1 (10) - We also thank Flip Nicklin,John Ford and the Japanese film crewfor 9 June 0 1 (Baffin Island, population. Journal of the Fisheries found that belugas were more likely than narwhals to be Research Board of Canada 281309-1318. absent from the study area when icebreakers were active. COSENS, S.E., and DUECK, L.P. 1988. Responses of migrating narwhal and beluga to icebreaker trafficat theAdmiralty Inlet ice-edge,N.W.T. in 1986. Hay (1984) found that early narwhal foetuses collected at In: Sackinger, W.M., and Jeffries, M.O., eds. Port and Ocean Engineering the same time varied in size. Usingthis variation and assum- under Arctic Conditions.Vol. 2. Fairbanks: Geophysical Institute, Univer- ing that all foetuses grow at the same rate, he calculated the sity of Fairbanks. 39-54. limits of the foetal growth curve and estimated the calving DEGERB0L, M., and FREUCHEN, P. 1935. Report of the mammals collected by the Fifth Thule Expeditionto arctic North America.In: Report of the Fifth period to be between 30 June and 29 August. Our results Thule Expedition 1921-24. Vol. 2, No. 4-5. Copenhagen: Gyldendalske suggest that, at least in some years, the calving period of Boghandel, Nordisk Forlag.1-278. narwhals begins at least one month earlier than this calcu- ELLIS,D.V. 1957. Some observations on mammals in the area between lated estimate. Our observations of newborn beluga calves Coppermine and Pond Inlet, N.W.T., during 1954 and 1955. Canadian are consistent with the existing literature for the eastern Field-Naturalist 71:l-6. FALLIS, B.W., KLENNER, W.E., and KEMPER, J.B. 1983. Narwhal surveys Canadian Arctic (Braham, 1984). and associated marine mammal observations in Admiralty Inlet, Navy It is not clear which parameters influence the length and Board Inlet, and Eclipse Sound, Baffin Island, N.W.T., during 1974-1976. variability of the calving period in these species. Observa- Canadian Technical Report of Fisheries and Aquatic Sciences1211.20 p. tions reported by Brodie (1971), Kleinenberget al. (1964) and GREENDALE, R.G.,and BROUSSEAU-GREENDALE,C. 1976. Observations of marine mammals at Cape Hay, Bylot Island during summer of 1976. Sergeant (1973) indicate that the peak calving period of Canada Department of the Environment, Fisheries and Marine Service belugas varies with locality. Comparable dataare not avail- Technical Report No. 680.25 p. able fornarwhals. Although Best and Fisher (1974)attribute HAY, K.A. 1984. The lifehistory of the narwhal(Monodon monoceros L.) inthe variation in the size of early narwhal foetuses to sampling of eastern Canadian Arctic. Ph.D. thesis, McGill University, Montreal. different populations, Hay (1984)assumes that the timing of and McCLUNG, R. 1976. Observations on beluga and narwhal inthe Canadian High Arctic,summer 1974. Fisheries Research Boardof Canada breeding by narwhals is similar in different parts of the Manuscript Report Series 1385.55 p. species range. KLEINENBERG,S.E.,YABLOKOV,A.V.,BEL'KOVITCH,B.M.,andTARASE- Sergeant (1973)found that the calving period of belugas in VICH, M.N. 1964. Beluga(Delphinapterus leucas): Investigation of the spe- Hudson Bay was more protracted than the mating period and cies. (Translated by Israel Program for Scientific Translations, Jerusalem, 1969.) suggested that the length of gestation must vary among MANSFIELD, A.W.,SMITH, T.G.,and BECK, B. 1975.The Narwha1,Monodon individuals. Individual variation in the gestation period of monoceros, in Eastern Canadian Waters.Journal of the Fisheries Research narwhals would broadenHay's (1984)estimate of their calv- Board of Canada 321041-1046. ing period and account forour early sightings of newborns in PORSILD, M.P. 1922. Scattered observations on narwhals. Journal of Mam- Lancaster Sound. malogy 41%-13. SERGEANT, D.E. 1973. Biology of white whales (Delphinapterus leucas) in The presenceof young narwhal andbeluga calves should Western Hudson Bay. Journal of the Fisheries Research Boardof Canada be considered in any discussions about increasing shipping 30:1065-1090. traffic in LancasterSound. The potential effects of underwa- TOMILIN, A.G. 1957.Mammals of the U.S.S.R. and adjacent countries.Vol. 9, ter vessel noiseon the ability of calves to communicate and Cetacea. (Translated by Israel Program for Scientific Translations, Jerusa- lem, 1967.) maintain contact with their mothers are unknown. Further VIBE, C. 1950. The marine mammals and marine fauna in the Thule district research is needed to determine whetheror not calf survival (N.W. Greenland) with observations on ice conditions in 1939, 1940, and is affected by increasedambient noise levelsdue to shipping. 1941. Meddelelser om Grenland150(6):1-117.