Interesting article about the Yukon chinook, if you substitute Columbia for Yukon the story is about the same. The primary differences are that subsistence fisheries are top priority in the Yukon, dams are not an issue, and there are not 180 hatcheries putting fish into the river. Significant similarities are there are many competing users over the length of the river, multiple state and federal agencies regulate the fisheries, and chinook life history.

Chinook spend more time in the ocean than the other Yukon salmon. In the article it is stated that little is known about chinook in the ocean, a view that is stated quite often by freshwater fisheries managers as a reason for failures of management schemes. The reality is that data on chinook in the ocean have been collected for many years, generally in conjunction with studies of the more numerous pinks, chum, and sockeye. For the past four years an international cooperative research project has been looking at the effects of climate change on salmon ecosystems in the Bering Sea. Juvenile chinook feed on the continental shelf in there first year at sea and then move off the shelf for their remaining time in the ocean. Old data indicates that the juvenile salmon were confined to a small area north of the Aleutian Islands. The Bering Sea has been warming up for the past several years. Sampling shows that as the water warms juvenile salmon are now utilizing most of the shelf. One can speculate that this dramatic increase in feeding area results in a higher survival of juvenile Yukon chinook, chum salmon and pink salmon. The warmer water doesn't increase the food supply in the Bering Sea basin however. When the chinook move off the shelf they are competing with increased numbers of chum and pink salmon from Japan, Russia, Canada, and the U.S. Their growth rate will be reduced resulting in more fish returning to the river but at a smaller average size. The loss of the 7 and 8 year old fish is not so easy to explain. Scale studies to determine their growth rates compared to the younger fish might give some clues.

Continuing the comparison to Columbia River chinook, they also feed on the continental shelf along the Oregon and Washington coast after leaving the river. Unlike the Bering Sea warmer water temperatures and no north winds decreases the food available. 2005 was not good for salmon (and seabirds) that rely on upwelling.

The article mentioned the need for research. The AYK SSI group is starting a significant research program this year. If anyone is interested in a comprehensive review of Western Alaska salmon look at the report, " Developing a Research and Restoration Plan for AYK Salmon", that can be accessed from the link below. It is 224 pages long so plan on reading for some time.

http://www4.nas.edu/cp.nsf/Projects+_by+_PIN/BEST-K-02-08-A?OpenDocument