STATUS OF THE PACIFIC WALRUS POPULATION, 1950-1989

The Pacific walrus (Odobenus rosmarus divergens) population is an impo rtant ecological and economic resource of the Bering Sea region. We de scribe population change, beginning with a low in 1950, through a high in about 1980, and ending in 1989. Estimates of abundance for the yea rs after 1989 were not attempted due to the lack of harvest data and o ther population parameters. Selective hunting practices resulted in bi ased data regarding population composition and reproductive performanc e. Rates of reproduction had to be estimated from ovarian data, which indicated a dramatic drop in the 1980s. High harvests in the 1980s lik ely contributed to a decline in the population, but uncertainties as t o accuracy of population estimates and other data raise reasonable dou bts, especially with respect to the number of males, for which the mos t recent (1985) population estimate suggests a sharp decline. Past pop ulation estimates were revised upwards to compensate for walruses unde rwater and not seen in aerial surveys. The weaknesses in the available data make it clear that effective management of the population will r equire many improvements in collection of data regarding harvests, pop ulation structure, reproduction, and population trend.