http://www.nmfs.noaa.gov/sfa/domes_fish/StatusoFisheries/2005/finalSOS/Appendices_2-5_FINAL.pdf

Page 38-39 talks about "overfishing" on West Coast Salmon

on September 27, 2000, the Pacific Fishery Management Council's (PFMC) criteria for an overfishing concern are met if, in three consecutive years, the post-season estimates indicate a natural stock has fallen short of its conservation objective (MSY, maximum sustainable production (MSP2), or spawner floor as noted for some harvest rate objectives) as listed in
Table 3-1 of the Salmon FMP. It is possible that a failure to meet conservation objectives for three consecutive years could result from normal variation, as has been seen in the past for several previously referenced salmon stocks which were reviewed under the PFMC's former overfishing definition. However, the occurrence of three consecutive years of reduced stock size or spawner escapements, depending on the magnitude of the short-fall, may signal the beginning of a critical downward trend which may result in fishing that jeopardizes the capacity of the stock to produce MSY over the long term if appropriate actions are not taken.