Population-specific aggregations of steelhead trout (Oncorhynchus mykiss) in the North Pacific Ocean

1997 ◽  
Vol 54 (10) ◽  
pp. 2368-2376 ◽  
Author(s):  
S McKinnell ◽  
J J Pella ◽  
M L Dahlberg

The distribution of North American hatchery-origin steelhead (Oncorhynchus mykiss) in the North Pacific Ocean varied by age and hatchery location. Columbia River steelhead were more abundant south of the Aleutian Islands at an earlier age than steelhead from the Georgia Basin (Georgia Strait, Puget Sound, and waters connecting with the open Pacific). Between 1984 and 1989, there were eight independent and coincident recoveries of coded-wire-tagged steelhead, where individuals released from hatcheries as juveniles at similar times and locations were recovered together on the high seas up to 3 years later. A statistical test was developed to determine whether these coincident recoveries should be expected if individual steelhead within populations travelled in the North Pacific in an uncoordinated manner. The overall test suggested that some tagged steelhead populations travelled together in a significantly (P < 0.05) coordinated manner on the high seas.

1989 ◽  
Vol 46 (7) ◽  
pp. 1147-1153 ◽  
Author(s):  
Brian Bigler

A recently documented scale characteristic of chum salmon (Oncorhynchus keta) originating from Hokkaido, Japan, has been found distributed almost exclusively among stocks of Asian origin. Scales from 10 544 chum salmon collected from 25 near-shore locations throughout the North Pacific Ocean were examined. Resorption of the scale focus, including instances where an easily visible hole had been formed, was found among 10.8% of Japanese chum salmon and 15.9% of chum salmon originating from the Soviet Union. In North America, this trait was infrequent (< 0.5%) among populations north of the Aleutian Islands, British Columbia, and Puget Sound, and was not found in Cook Inlet, Prince William Sound, and Southeast Alaska. Focal scale resorption arises from osteoclastic cellular activity, most likely following the first winter of life, and remains as a permanent mark thereafter. This unique, uniformly occurring, easily identifiable scale characteristic will provide a valuable tool for stock identification. Evidence of focal scale resorption is also reported in sockeye (O. nerka), coho (O. kisutch), and king salmon (O. tshawytscha), but was not found in pink salmon (O. gorbuscha), sampled from locations in Alaska.


1992 ◽  
Vol 86 (4) ◽  
pp. 792-810
Author(s):  
Marian Nash

On May 19, 1992, President George Bush transmitted to the Senate for advice and consent to ratification the Convention for the Conservation of Anadromous Stocks in the North Pacific Ocean, with Annex, signed at Moscow on February 11, 1992. An accompanying report by Secretary of State James A. Baker III, dated May 14, 1992, stated, in major part: The Convention has as its centerpiece a prohibition on high seas fishing for Pacific salmon, which will protect valuable migrating U.S.-origin salmonids. It also establishes a new international organization to promote the conservation of anadromous stocks (primarily Pacific salmon) throughout their migratory range in the high seas area of the North Pacific Ocean and its adjacent seas, as well as ecologically related species that interact with these resources, including various marine mammals, seabirds, and non-anadromous fish species. The new organization, which is to be known as the North Pacific Anadromous Fish Commission, will also serve as a needed venue for consultation and coordination of high seas fishery enforcement activities by the contracting parties.


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