GROWTH AND SEXUAL DIMORPHISM OF ATLANTIC WALRUSES (ODOBENUS-ROSMARUS-ROSMARUS) IN FOXE BASIN, NORTHWEST-TERRITORIES, CANADA

Growth of Atlantic walruses (Odobenus rosmarus rosmarus) was investiga ted using morphological data collected in association with Inuit subsi stence walrus hunts. Four growth models were examined. The growth para meters of a constrained Richards model were used to quantify growth an d to test for sexual dimorphism. The asymptotic length of male walruse s (315.2 cm +/- 3.8 (SE), n = 103) was significantly larger (t = 7.21, df = 191, P < 0.05) than the asymptotic length of females (276.6 cm /- 3.4, n = 90). Sexual size dimorphism in adults was due to a longer growth period and a faster growth rate in males. The predictive equati on relating mass (M, kg) to standard length (SL, cm) was: Log(10)M = - 3.74 + 2.68(Log(10)SL), n = 25, r(2) = 0.98. There were no significant differences in the size of male walruses from Foxe Basin collected in the 1950s and this study. There were too few data to compare females. There were no significant differences in size between walruses sample d in Greenland and Foxe Basin in the 1980s and 1990s. Foxe Basin walru ses were significantly larger than walruses sampled in northern Hudson Bay in the 1950s. Female Atlantic walruses sampled in Foxe Basin were larger than female Pacific walruses (Odobenus rosmarus divergens) sam pled in Alaska.