Polycystic lesions in the liver of the white sturgeon

Polycystic lesions have been reported from the kidney and liver of many different fish species and are attributed to pollution and genetic anomalies. In June 2002, eggs and milt were collected from two female and five male white sturgeon Acipenser transmontanus below Bonneville Dam on the Columbia River. Fertilized eggs were hatched at the Abernathy Fish Technology Center in Longview, Washington, and 20,000 juveniles were raised for approximately 1 year before release into the wild. Just before release, 12,000 juveniles were scute-marked, during which it was noticed that about 30 fish had distended abdomens. Gross necropsy revealed a large, jellylike mass in the peritoneal cavity. Histopathological examination of four fish showed that this growth was a polycystic lesion of liver tissue. This is the first report of this type of lesion in white sturgeon and is presumed to be the product of a genetic anomaly.