Thursday August 1, 2024
Nature —
Salmon raised in captivity and released into rivers bound for the North Pacific are breeding with wild salmon, raising concerns among scientists about the fishes’ future. A new study1 published this month on pink salmon (Oncorhynchus gorbuscha) in Alaska predicts that such interbreeding will increase the size of the species’ population but decrease its diversity. This could change mating behaviours in wild fish, making them less resilient to climate change and other disasters.
“There are too many fish being released,” says Peter Westley, a fisheries ecologist at the University of Alaska Fairbanks and an author of the paper. He suggests that pink-salmon hatcheries reduce their output.
Fishery regulators are resisting calls to scale back operations, however, citing lingering unknowns about the ecological interactions between wild and hatchery-bred fish, as well as economic competition from neighbouring Russia.