Robin W. Baird, Pam J. Stacey, David A. Duffus and Ken M. Langelier
Reports of the International Whaling Commission Special Issue 17: in press.
Abstract: Gray whale (Eschrichtius robustus) mortality incidental to commercial fishing operations in British Columbia (B.C.), Canada was evaluated by two methods: 1) a mail-out questionnaire survey of all commercial fishing licence holders in the province, and 2) a review of records of incidental catches, strandings and dead floating animals from published and unpublished sources. From 5,375 surveys sent out, 848 were returned, a response of 16% Of these, 729 were used in the analysis; the remainder were excluded as incomplete. Forty-two incidents with gray whales were reported, including three mortalities. From sources other than the questionnaire, 41 records of stranded and dead floating gray whales were obtained, of which 4 were judged to have been killed incidental to fishing operations. Twenty-six of these animals had not been examined closely, but extrapolation from the 15 detailed records suggest that 27% of the dead gray whales reported in B.C. die incidentally in fisheries. Collisions with fishing gear are estimated to occur approximately 20 times per year. Mortality occurs in salmon drift gillnet, salmon seine, longline and trap fisheries. There is also one record of an individual entangling and drowning in a herring net pen, as well as an individual entangling in a herring set gillnet. Estimates of annual mortality are approximately 2 individuals using data obtained from the questionnaire, and 2.4 individuals using stranding data. Biases are present for both sampling methods, but the estimated mortality levels are very small relative to population size.