COHO SALMON 



Figures 90-104 



Coho salmon are produced in Asia and North 

 America in numerous small streams as well as in 

 tributaries of larger rivers. In Asia, coho salmon occur 

 at least as far north as the Anadyr River and occur in 

 mainland streams southward to the Amur Firth and 

 the Islands of Sakhalin and Hokkaido. In North 

 America, coho salmon occur from at least as far north 

 as Cape Thompson in the Chukchi Sea south to 

 streams tributary to Monterey Bay, Calif. (Godfrey 

 1965). 



Although accurate estimates of the size of either 

 Asian or North American stocks are virtually impossi- 

 ble to determine, it has been estimated (on the basis 

 of commercial and sports catches) that North 

 American stocks are somewhat larger than Asian 

 stocks. The ratio of average annual catches of coho 

 salmon for the period 1954-61 has been in the order of 

 5 million fish in Asia and 7 million fish in North 

 America (Godfrey 1965). 



Coho salmon as a rule spend but one winter in the 

 ocean, and the high-seas tagging experiments were on 

 the maturing individuals which return to spawn that 

 same year. During 1964-69 the Fisheries Research 

 Institute, University of Washington, fished in coastal 

 waters with small mesh purse seines for the purpose of 

 capturing and tagging age .0 fish. Coho salmon from 

 these taggings would return the following year as 

 matures. 



Coastal Recoveries in Year Tagged 



The tagging effort for coho salmon (Fig. 90) as well 

 as the total returns from tagging (Fig. 91) indicates 

 that the ocean distributions of Asian and North 

 American coho salmon do not overlap extensively. 

 The several returns from immediately south of the 

 central Aleutians (long. 175°W-177°W), however, 

 produced several returns to both Asia and North 

 America. Only two returns were from releases in the 

 Bering Sea. 



Asian stocks (Figs. 92, 93). — Returns of coho 

 salmon to Asian streams (Fig. 92) were from tag 

 releases in the northwestern Pacific Ocean mainly 

 north of lat. 48°N and west of long. 170°E. Eleven 

 returns were from the Aleutian Islands area. Nine 

 returns were from tagging south of the central Aleu- 

 tian Islands which compares with 12 returns in 

 northern and western Alaska from this area (see Fig. 

 94) . This particular area constitutes the known area of 

 overlap of Asian and North American stocks. 



Sakhalin Island to west Kamchatka. — Tagged 

 coho salmon recoveries in streams emptying into the 

 Okhotsk Sea (Sakhalin Island to west Kamchatka 

 (Fig. 93)), with two exceptions, came from releases 

 south and east of the southern tip of Kamchatka 



Peninsula. The single fish recovered in Sakhalin 

 Island was from a release near lat. 52° N and long. 

 168°E, and one recovered in west Kamchatka was 

 released near lat. 49°N and long. 169°E; those were 

 the easternmost points for releases recovered in a 

 Okhotsk Sea tributary. 



East Kamchatka to the Siberian coast. — Coho 

 salmon tag recoveries in the areas from east 

 Kamchatka to the Karaginskii District (all but one 

 from east Kamchatka and the Kamchatka River) 

 were primarily from tagging in the northwestern 

 Pacific Ocean east of the Kamchatka Peninsula and 

 from the central Aleutian Islands area (Fig. 93). The 

 northernmost recovery of a tagged coho salmon was 

 made in the Karaginskii District from a release south 

 of Adak Island in the central Aleutian Islands. 



Although the difference was not pronounced, the 

 distribution of coho salmon from east Kamchatka was 

 slightly north of those from west Kamchatka which in 

 turn were slightly north of the fish returning to the 

 Okhotsk Sea coast and Shelekhova Bay. 



North American stocks (Figs. 94-101). — Recov- 

 eries of tagged coho salmon in North America were 

 made from the Yukon River in northern Alaska to 

 California (Fig. 94). The westernmost tagging location 

 of a coho salmon returning to North America was near 

 long. 177°W, south of Adak Island. Most tagged coho 

 salmon returning to North America were from the 

 northeastern Pacific Ocean. 



The only area of intermingling of Asian and North 

 American maturing coho salmon, shown by the tag- 

 ging data as explained previously, was south of the 

 central Aleutian Islands between long. 175°W and 

 177°W. 



Northern and western Alaska. — Recoveries made 

 in northern and western Alaska are illustrated in 

 Figure 95. The coho salmon from the Yukon and 

 Kuskokwim rivers came from the same general tag- 

 ging points, south of Adak Island and in the 

 northeastern Pacific Ocean south of lat. 49°N and 

 east of long. 154°W. The recoveries illustrate exten- 

 sive migrations of these stocks. Returns to Bristol Bay 

 streams show three returns to the Nushagak River 

 from tagging south of Adak Island and one return to 

 the Ugashik River from tagging south of Kodiak 

 Island. 



Northeast Pacific coastal areas. — Tag recoveries 

 of coho salmon in coastal areas from south of the 

 Alaska Peninsula to Puget Sound (Figs. 96-101) in- 

 dicate that the distribution of these stocks is in the 

 northeastern Pacific Ocean. With one exception all 

 returns were from tagging east of long. 156° W. The ex- 

 ception was the recovery on Kodiak Island of a fish 

 released south of the central Aleutian Islands (Fig. 

 96). Although the returns were relatively few they il- 

 lustrate that coho salmon were distributed 



67 



