Ocean Fishery Impacts
by Robert Kope, NOAA Fisheries
This is in response to your voice message asking about fishery impacts on Idaho salmon and steelhead. I've tried calling, but get no answer or machine.
Sockeye, steelhead, and spring Chinook are not caught in coastal fisheries in numbers high enough to estimate what the impacts are. They all rear in the central North Pacific and are only vulnerable to coastal fisheries briefly during their spawning migration, and then only when that coincides with open periods in coastal fisheries. They used to be caught in significant numbers in the high-seas driftnet fishery. But that was banned in 1993 with the signing of the Convention for the Conservation of Anadromous Stocks in the North Pacific Ocean. The Convention banned salmon fishing in international waters north of 33 degrees N latitude (About the latitude of San Diego). The US, Canada, Russia, Japan, and Korea are all members of the convention (www.npafc.org), so Taiwan is the only country that ever did fish for salmon in the N Pacific that has not signed the convention. The convention members control the freshwater habitat for all anadromous salmond production and and are pretty serious about enforcement of the ban in international waters, so poaching is no longer much of an issue.
Fall Chinook are the only stock from Idaho that is significantly impacted. They have marine distribution that is mainly over the continental shelf and they are caught in ocean salmon fisheries from Southeast Alaska to central Califronia. NMFS consultation standard is that fishery impacts must remain at less than 70% of what they were during some base period. We assess the impact using the Lyons Ferry hatchery stock as an indicator. The distribution of impacts is reported annually to the Pacific Salmon Commission by their Chinook Technical Committee. The most recent numbers are in appendix table E.72 on page 191 of report TCCHINOOK (08)-2 which can be downloaded in pdf from the PSC website at www.psc.org/publications_tech_techcommitteereport.htm These numbers are not true exploitation rates because they do not account for adult losses during upstream migration in the Columbia River, and they are reported on a calendar year basis so they don't account for the fact that some fish impacted in the ocean would not have spawned, but would have remained another year or more where they would have been subject to additional natural mortality. Both of these omissions tend to bias the estimated fishery impacts high. The table shows that for the 1999-2006 period, spawning escapement accounted for 72.2% of the mortalities that can be accounted for. In other words, fisheries accounted for approximately 27.8% of the mortality. The US net fishery is in the river, and accounted for 9.1% of the mortalities, so all ocean fisheries combined had about a 18.7% mortality rate.
Columbia River Compact Reports
Regional Mark Processing Center
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