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Mass fish necropsy helps forecast salmon returns in Oregon
In a small lab at the Hatfield Marine Science Center in Newport, scores of scientists, students and volunteers paw over trays of fish. They’re here for the annual fish necropsy organized by Oregon State University and the National Ocean and Atmospheric Administration. Cheryl Morgan, the principal investigator here for OSU, leans over a tray with a scalpel and swiftly cuts open the head of a juvenile coho. “This one has a tag,” she explains. “It’s a tiny, thin piece of wire in its snout somewhere that tells us when and where it was released.” She digs around trying to find the wire, makes another cut, then digs around some more. The mass necropsy is not for the faint of heart. But by sampling a couple thousand fish each year, biologists learn how young salmon are faring in the ocean. It’s a keystone study that started in the 1990s, when several species of salmon were listed under the Endangered Species Act. Scientists back then knew a lot about why the fish were struggling in rivers. They knew about the dams, gas bubble disease and the lack of habitat. But they had little idea what was happening in the ocean. Since then,...