DETROIT — King salmon has helped create a multibillion-dollar sport fishery in the Great Lakes, but ripple effects of invasive species have left the fish’s future less certain.
The king, or chinook, salmon was first transplanted into the Great Lakes from the Pacific Northwest about 50 years ago. The species led a turnaround in the area’s fishery by helping create a $7 billion economic impact, the Detroit Free Press reported.
But the spread of invasive zebra and quagga mussels has led to steep population declines of the alewife, a species that serves as the salmon’s almost exclusive diet.
The Michigan Department of Natural Resources is trying to regain balance between predator and prey by reducing its salmon stocking. Stocking is when fish are raised in a hatchery and released into the lake to increase the existing population.
Michigan stocked nearly 1.7 million salmon into the Great Lakes in 2012. This year, the state’s chinook stocking number was cut to 330,000 fish.
“It’s been invasive after invasive. We’re dealing with a very different ecosystem,” said Jim Dexter, chief of the department’s fisheries division. “But even with that, we still have an excellent fishery. The intent is to maintain those diverse fisheries well into the future. (But) different species will be available in different proportions than people are used to.”
Fishing businesses near Lake Michigan said they’re not panicking, and have actually noticed an uptick this year.
“This is the first year we’ve really seen an increase in the alewife population in a while,” said Mike Boyd, owner and of Coldwater Charters. “Most every time we caught a fish, the fish we caught had alewives in them.”