ARS | Publication request: Preliminary examination of oxidative stress in juvenile spring Chinook salmon (Oncorhynchus tshawytscha) of wild origin sampled from transport barges

Submitted to: Journal of Fish Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2009
Publication Date: December 1, 2009
Repository URL: http://hdl.handle.net/10113/43762
Citation: Welker, T.L., Congleton, J.C. 2009. Preliminary examination of oxidative stress in juvenile spring Chinook salmon (Oncorhynchus tshawytscha) of wild origin sampled from transport barges. Journal of Fish Biology. 75:1895-1905.

Interpretive Summary: Construction of hydroelectric dams on the Snake and Columbia Rivers and their tributaries has greatly altered the riverine ecosystem and produced conditions deemed unfavorable for out-migrating juvenile salmonids (e.g. increased travel time, elevated water temperature, exposure to predators, passage through hydroelectric turbines, and gas supersaturation). To reduce exposure to unfavorable conditions in the Snake-Columbia River hydrosystem, juvenile salmonids are collected at dams on the Snake and Columbia Rivers, loaded onto trucks or barges, and transported and released 235 km upstream of the mouth of the Columbia River. Although transportation reduces exposure to the hydrosystem, it may adversely affect out-migrants by potentially increasing horizontal transmission of pathogens or by elevating stress levels. Stress is known to be detrimental to fish and can increase susceptibility to disease, but it can also lead to other negative effects on fish health and physiology, such as oxidative stress. Reactive oxygen species, the causative agents of oxidative stress, are formed continuously in animals as a consequence of normal aerobic cellular metabolism. However, oxidative stress is also stimulated by increased stress and a host of environmental factors. To evaluate whether stress on transport barges increased oxidative stress in juvenile wild Chinook salmon, fish were collected and loaded onto transport barges at Lower Granite Dam on the Snake River and then sampled from barges at John Day Dam, 348 km downstream, at five-day intervals beginning late April and ending late May. An increase in peroxidative damage to membrane lipid and decrease in vitamin E in liver were observed from early to late in the barge transportation season. These changes seemed unrelated to the stress response or the concentration of n-3 highly unsaturated fatty acid (HUFA) concentrations in tissue but may be related to water temperature, which increased during the transport season.

Technical Abstract: Migrating juvenile wild Chinook salmon (Oncorhynchus tshawytscha), collected and loaded onto transport barges at Lower Granite Dam on the Snake River, were sampled from barges at John Day Dam, 348 km downstream, at five-day intervals beginning late April and ending late May. An increase in lipid peroxidation and decrease in vitamin E in liver were observed from early to late in the barge transportation season. These changes seemed unrelated to the stress response (plasma glucose and cortisol levels declined from early to late in the season) or the concentration of n-3 highly unsaturated fatty acid (HUFA) concentrations in tissue but may be related to water temperature, which increased during the transport season.