Pollution may be factor in sturgeon decline

CORVALLIS , Ore. – Chemical pollution may be a factor in the decline of Columbia River white sturgeon, researchers say.

The chemicals include the insecticide DDT and polychlorinated biphenyls – or PCBs, according to Oregon State University scientists.

Their studies have shown 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,” said Carl Schreck, an OSU biologist. “The fish move, the stuff they eat moves and the water and sediments bearing the contaminants moves.”

Schreck and fellow biologist Grant Feist studied white sturgeon from three reservoirs along the Columbia River and from areas downstream of Bonneville Dam, the first one encountered by fish swimming upriver.

The researchers found some of the fish in reservoirs behind the dams had concentrations of chemicals up to 20 times higher than the fish below Bonneville.

“We believe that some contaminants are accumulating behind the dams by settling out in the sediment as the water slows,” Feist said.

During the last 25 years, white sturgeon have experienced a sharp drop in population in the upper reaches of the Columbia River. In 1990, the Committee on the Status of Endangered Wildlife in Canada designated the white sturgeon as “vulnerable,” only to reclassify it as “critically imperiled” in 1994.

Sturgeon can grow to 20 feet in length and live for 100 years.