Hatchery Fish
Fish from hatcheries that release billions of salmon and trout each year can have serious problems reproducing in the wild, according to a study out of Oregon State University.
Steelhead trout from hatcheries are 40 percent less successful at producing offspring that survive to adulthood than wild trout. Nearly five billion hatchery fish are released each year. Steelhead and salmon are closely related and spend several years at sea before returning to their native streams and rivers to spawn.
While there has been concern about the ability of hatchery fish to survive in the wild, the study shows a much more serious problem. It shows hatchery fish have trouble reproducing, and scientists fear they could be weakening the wild stocks with which they breed.
Fish are typically produced in hatcheries by taking eggs and milt from trout and salmon returning to rivers and streams to spawn. After the young fish hatch, they are grown in outdoor ponds for up to a year before being released into the wild.
The study measured the reproductive success of the first two generations of hatchery fish that bred in the wild by counting how many adults of each generation returned to spawn.
October 8, 2007 8:14 AM | Category: Fish