Several studies have indicated that the rainbow trout (Oncorhynchus mykiss) loses ultraviolet (UV) sensitivity and the associated UV-sensitive corner cones when the animal transforms from a small (parr) juvenile to a larger, silver-coloured, smolt. Similar changes supposedly take place when parr juveniles are treated with thyroid hormone (T(4)) or retinoic acid. In contrast to previous investig...

Dams designed for hydropower and other purposes alter the environments of many economically important fishes, including Chinook salmon (Oncorhynchus tshawytscha). We estimated that dams on the Rogue River, the Willamette River, the Cowlitz River, and Fall Creek decreased water temperatures during summer and increased water temperatures during fall and winter. These thermal changes undoubtedly i...

Results from surveys of the western Bering Sea and adjacent Pacific epipelagic waters, performed by TINRO-Centre are reported. Surveys of the nekton community were conducted from 1986 through 2005, annually. Information on the distribution of all chum salmon by age group, the abundance and biomass of chum salmon, and other fish in the western Bering Sea and adjacent Pacific Ocean water are repo...

In order to increase the size of declining salmonid populations, supplementation programmes intentionally release fish raised in hatcheries into the wild. Because hatchery-born fish often have lower fitness than wild-born fish, estimating rates of gene flow from hatcheries into wild populations is essential for predicting the fitness cost to wild populations. Steelhead trout (Oncorhynchus mykis...

OBJECTIVES Fish can be exposed under environmental conditions to multiple stressors including natural toxins and environmental or feed contamination at the same time. This study brings new knowledge about the effects of controlled exposure to multiple stressors in fish. The aim of this study was to test the hypothesis that influence of cyanobacterial biomass and arsenic in feed can combine to e...

Competition for shared resources is typically invoked as the most important ecological interaction promoting diversification and speciation, whereas the roles of abiotic variables and natural enemies have been largely neglected. To improve our understanding of the ecological factors involved in the evolution of sympatric stickleback species pairs (Gasterosteus aculeatus), I examined whether lak...