The research by Carl Schreck and Grant Feist, biologists in OSU's College of Agricultural Sciences, has been published in the journals Environmental Health Perspectives and Archives of Environmental Contamination and Toxicology.
Their research shows that white sturgeon living in the Columbia River in some areas above Bonneville Dam have high amounts of toxic contaminants in their livers, sex organs and muscle tissue.
"We don't know the exact source of contamination," Schreck said. "The fish move, the stuff they eat moves and the water and sediments bearing the contaminants moves. The Columbia receives input from numerous sources, so any population of fish at any one site can be exposed to a myriad of substances."
The OSU researchers say it is difficult to estimate the numbers of sturgeon in the Columbia, but there has been a noticeable decline in the number of young fish, indicating productivity is poor, especially in the impounded areas above dams.
In the past, any decreases in population were thought to be linked to the presence of dams, which have changed the temperature and flow of the river. And despite fish ladders in place for salmon, the bottom-dwelling white sturgeon rarely navigate dams successfully making it difficult for them to expand their habitat or access oceanic food sources.
Schreck and Feist studied white sturgeon from three reservoirs along the Columbia River and from areas downstream of Bonneville, the last dam on the river in its path to the Pacific Ocean. The researchers found some of the fish living in reservoirs behind the dams had concentrations of chemicals up to 20 times higher than the fish below Bonneville. The contamination was most sig
Source:Oregon State University