January through April. Without knowing the rate of ex- 

 change or the frequency of intermixing among years, it is 

 impossible to evaluate whether we are dealing with one, two, 

 or perhaps as many as four breeding stocks of white whales 

 in the Bering and Chukchi Seas. White whales which are har- 

 vested by Alaska Eskimos in summer, as in Kotzebue Sound 

 and adjacent bays, as well as those along the northwest coast 

 probably should be considered management stocks because 

 of the timing of harvest occurring simultaneously with repro- 

 duction. 



Life History and Associated Information 



Reproduction 



The average age at sexual maturity for female white whales 

 in eastern Canadian Arctic waters has been reported to be 5 yr, 

 at 270 cm long or 85% full adult length (Doan and Douglas 

 1953; Brodie 1971; Sergeant 1973). Males, on the average, 

 were reported by Brodie (1971) and Sergeant (1973) to be sex- 

 ually mature at 8 yr of age. Kleinenberg et al. (1964) found 

 that female white whales in the eastern Siberian Arctic at- 

 tained sexual maturity at an average age of 3 yr, at 247-470 

 cm in length, compared with 2-3 yr and 380-450 cm for males 

 (Dorofeev and Klumov 1936). Disagreement in calculated age 

 at sexual maturity between the Soviet and Canadian data 

 may be due to the poor state of knowledge concerning ageing 

 methodology at the time of the earlier studies. 



Calving and mating apparently occur simultaneously from 

 May through August in eastern Siberian and Canadian 

 waters (Vladykov 1944; Laws 1959; Sergeant 1962, 1973; 

 Kleinenberg et al. 1964; Brodie 1971; Nishiwaki 1972). Simi- 

 larly, Belkovich (1960) found that in the Soviet Arctic (White 

 to Kara Seas) calving occurred from mid-June to mid-July, 

 later to the east. Calving in Alaska is believed to commence 

 in May or June (Klinkhart 1966); however, young calves are 

 commonly seen by coastal Eskimo residents as early as 

 March. Young of the year and neonatal calves have been 

 seen in April and May each of the 4 yr we have been studying 

 bowheads along the northwest coast of Alaska (Braham et al. 

 1979, 1980c). Small young of the year calves were observed 

 by the senior author 100 km north of Barrow on 28 Septem- 

 ber 1979. Calving may therefore occur into late summer or 

 early autumn. Mating locations in the eastern Bering Sea are 

 southeast Kotzebue Sound, Bristol Bay, Yukon Delta-Norton 

 Sound, and along the northwest coast of Alaska, particularly 

 near Peard Bay. 



White whales are reported to give birth nearshore to single 

 calves averaging 150 cm in length (Doan and Douglas 1953; 

 Sergeant 1962; Kleinenberg et al. 1964). Newborn calves have 

 been observed in river estuaries of the eastern Canadian Arc- 

 tic (Brodie 1969; Sergeant 1973) and western Canadian Arc- 

 tic, specifically, the Mackenzie River estuary (Sergeant and 

 Hoek 1974). 



Cows are believed to nurse calves for approximately 24 

 mo. Brodie (1971) and Sergeant (1973) estimated lactation 

 periods of 24 mo and 21 mo, respectively, for white whales in 

 eastern Canadian Arctic waters. Kleinenberg et al. (1964) 

 estimated the lactation period in Siberian Arctic waters to be 

 5-6 mo. 



Given a gestation period of approximately 12-15 mo (Vlad- 

 ykov 1944; Belkovich 1960; Kleinenberg et al. 1964; Brodie 



1971; Nishiwaki 1972; Sergeant 1973) and no more than a 2- 

 yr lactation, and assuming a cow nurses one calf at a time, 

 the reproductive cycle for white whales could last up to 3 yr. 

 Female white whales have been reported to mate on the aver- 

 age once every 2-3 yr (Degerboel and Freuchen 1935; Brodie 

 1971; Sergeant 1973). 



Food Habits 



White whales feed on fish, mainly, and invertebrates in estu- 

 aries, small streams, and rivers and in bays near the mouths of 

 rivers and on occasion, considerable distances up rivers. In 

 these areas they feed midwater to the bottom on organisms sel- 

 dom found deeper than 50 fathoms (Doan and Douglas 1953; 

 Sergeant 1962, 1968; Kleinenberg et al. 1964). 



Prey consumed in the eastern Canadian Arctic (Vladykov 

 1946; Doan and Douglas 1953; Sergeant 1973) and Siberian 

 Arctic (Kleinenberg et al. 1964) are more thoroughly docu- 

 mented than in the western Canadian and Alaskan Arctic. 

 For the Hudson Bay-Churchill region Sergeant (1968) re- 

 ported that the most common species of fish consumed by 

 white whales was capelin, which spawns in shallow water 

 close to river mouths, July-August. River fish, ciscos and 

 pike, marine worms, and squid are also taken. In Hudson 

 Bay's Whale Cove area, where capelin do not occur, white 

 whales forage primarily on decapod shrimp (bottom dwellers), 

 Arctic char, Greenland cod, and polar cod. 



Sergeant and Hoek (1974) reported that prey taken by 

 white whales in offshore areas of the Beaufort Sea in de- 

 creasing order of importance were squid, fish, and Crustacea. 

 The fish included lake herring and possibly Pacific herring. 

 Fraker et al. (1978) reported polar cod and squid to be com- 

 mon offshore species consumed by white whales in the Beau- 

 fort Sea and Amundsen Gulf. Prey species taken in the U.S. 

 Beaufort Sea are unknown, but Arctic cod is an abundant 

 species in the western Arctic. White whales resident to Bristol 

 Bay and Cook Inlet feed on five species of salmon, smelt, 

 flounder, sole, sculpin, blenny, lamprey, two types of 

 shrimp, and mussels, May to August (Alaska Department of 

 Fisheries 1955, 1956; Alaska Department of Fish and Game 

 1957). Prey taken by white whales in the coastal waters of the 

 Chukchi Sea vary greatly: Saffron cod, sculpins, capelin, rain- 

 bow smelt, Arctic cod, herring, whitefish, char, salmon, 

 suckers, cragonid shrimp, isopods, snails, octopus, gonatid 

 squid, and polychaetes (Lowry et al. 1980). 4 ' 



Group Composition 



Group size varies seasonally. Large pods congregate in the 

 early spring until the breakup of the pack ice (Kleinenberg et 

 al. 1964). Once this occurs they form smaller groups of two to 

 four individuals which spread out over several kilometers until 

 the summering areas are reached (Kleinenberg et al. 1964; 

 Fraker footnote 24). However, larger groups have been ob- 

 served in April and May during our aerial studies and at Point 

 Barrow and Point Hope. In the summering areas the whales 

 assemble into large congregations for feeding and/or repro- 



"Lowry, L., K. Frost, and J. Burns. 1980. Trophic relationships among ice- 

 inhabiting phocid seals and functionally related marine mammals in the Chukchi 

 Sea. Unpubl. final OCSEAP report, RU232, 58 p. Alaska Dep. Fish Game, 1300 

 College Road, Fairbanks, AK 99701 . 



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