Japanese studies on the early ocean life of juvenile
Abstract: Almost all the salmon resources in Japan have been supported by artificial enhance-ment, and because of the success of this program the population size of chum salmon (Oncorhyn-chus keta) has increased dramatically since the early 1970s. About 90 % of Japan's salmon catch is chum; 5–1...
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| Format: | Text |
| Language: | English |
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2003
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.576.7761 http://www.npafc.org/new/publications/Bulletin/Bulletin No. 3/Pages 41-68 (JapanReview).pdf |
| Summary: | Abstract: Almost all the salmon resources in Japan have been supported by artificial enhance-ment, and because of the success of this program the population size of chum salmon (Oncorhyn-chus keta) has increased dramatically since the early 1970s. About 90 % of Japan's salmon catch is chum; 5–10 % is pink salmon (O. gorbuscha) and 0.5 % masu (O. masou). Therefore, biological research has focused on the early ocean life of juvenile chum salmon to establish the proper timing and size for release of juveniles from hatcheries, and, since the late 1960s, to study the distribution and movement of juvenile salmon in nearshore waters. Survey results indicated that juvenile chum salmon remained in coastal water masses with good food conditions and physiologically optimum surface temperature and salinity until they reached about 70–80 mm FL, when they were able to migrate offshore, avoiding high SST (over 12–13ºC) and high salinity (over 34 pus). Japan-Russia cooperative juvenile salmon surveys were conducted in the Okhotsk Sea and the western North Pacific Ocean, from early summer to winter in 1988–1996. Results suggest that the Okhotsk Sea |
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