EXXON VALDEZ Oil Spill Restoration Project 99188 Final Report: Otolith Marking of Pink Salmon in Prince William Sound Salmon Hatcheries

摘要

In the fall of 1995, 1996, and 1997, thermal marks were applied to otoliths of all hatchery pink salmon in Prince William Sound (PWS). The marks were highly visible on voucher samples taken from hatchery fry in the spring of 1996, 1997 and 1998. For brood year 1996 and 1997 pink salmon, accessory thermal marks, applied after the fry hatched, allowed identification of within-hatchery treatment groups. Double-blind tests were conducted to assess the ability of laboratory personnel to correctly identify hatchery otolith marks laid down in brood years 1995-1997 salmon. The tests indicated that the probability of a successful identification between hatchery and wild pink salmon was 99.6%, 99.7% and 99.3% for brood years 1995-1997, respectively. Catch-sampling and estimation protocols were used to estimate the contribution of hatchery fish to PWS 1997 and 1998 pink salmon commercial fisheries. Preliminary estimates of the stock composition of an area-time specific catch were available within 24 hours after fishery closures.