New ways to track fish

Scientists increasingly rely on new fish-tracking devices to help them recover imperiled species and get rid of nuisance ones.

Sonic tags, as small as a lipstick tube and less than a gram planted inside a fish, have been fitted in more species in more conditions to collect more information. The devices help pinpoint movements as fish approach dams and other structures.

Researchers tracked a fish that a pelican nabbed in Lake Davis near Portola to Pyramid Lake in Nevada. Other tagged species include sharks, swordfish, turtles, sturgeon and salmon.

Scientists also track nonnative fish so they can eradicate them easier, says Roland Knapp, a UC Davis fisheries biologist.

For example, brook trout overran many Sierra lakes and streams, and Jim Edmondson of CalTrout says “there may be cases where brook trout should not continue to be around.”

-- Emmett Berg