Can cormorants help control Great Lakes invaders?

By ERIC FREEDMAN
Capital News Service
LANSING — Double-crested cormorants are the bane of many Great Lakes anglers, devouring prize game fish and damaging the sport and commercial fishery. At least that’s a widely held belief about these birds — and a generally wrong one, Northern Illinois University researchers say. Cormorants’ fish-stealing rep may be a bum rap — and the truth is more complex, as the first dietary study of cormorants in southern Lake Michigan shows. Even better news: The cormorants are chowing down instead on invasive species — mainly alewife, round goby and white perch — which together accounted for 80 to 90 percent of their diet. “Because this is the first such study to be completed in southern Lake Michigan, its results will help to inform discussion among local stakeholders and will provide valuable data to other researchers studying cormorant diet in the region,” said lead author Patrick Madura, who led the study as a master’s student.

Fate of popular sport-fishing tradition at risk

By KEVIN DUFFY
Capital News Service
LANSING — After a half-century of salmon fishing in the Great Lakes, anglers are on edge. As numbers of native lake trout and whitefish rebound, numbers of the prized Chinook – or king – salmon have spiraled downward. “It’s about finding a balance between prey fish and predators in this changing food web,” said Randy Claramunt, a fisheries research biologist with the Department of Natural Resources (DNR). “We don’t want to have a fish community that’s dominated by non-native species,” he said. “But in some cases it can provide a benefit.”
The rise and fall of salmon in the Great Lakes is a cautionary tale that suggests an ecosystem cannot be restored with single-species thinking.

Coldwater bacteria threatens Great Lakes salmon

By ERIC FREEDMAN
Capital News Service
LANSING — A bacterial disease that sickens fish whether raised in captivity or in the wild is imperiling popular salmon species in the Great Lakes Basin, a new study shows. The findings are based on testing lake, brook, brown and rainbow trout and Coho, Atlantic, chinook and steelhead salmon from the Lake Huron, Lake Michigan and Lake Superior watersheds, as well as fish used for breeding at state hatcheries in the Upper Peninsula and northern Lower Peninsula. Bacterial coldwater disease “threatens wild and propagated members of the salmon family worldwide” and can cause substantial economic damage, according to the study by scientists at Michigan State University. It’s the first comprehensive examination of the prevalence of the bacterium in the Great Lakes Basin. The disease is caused by a bacterium known as Flavobacterium psychrophilum, which has been associated historically with more fish deaths “than all other fish pathogens combined” at state hatcheries, according to the study.

Salmon face spawning season challenges

By AMELIA HAVANEC
Capital News Service
LANSING – Every fall, thousands of chinook and coho salmon return to northern Michigan rivers to spawn, counted at state collection sites in Manistee County and Traverse City. But this year’s fishing season has its own set of challenges – a balancing act between weather and food supply has gone off-kilter – with fewer salmon as a consequence. “From what we’re seeing, it’s looking like a pretty low year,” said Edward Eisch, the Department of Natural Resources (DNR) acting fish production manager. Salmon fishing has been part of a 50-year saga since Pacific salmon were introduced to Lake Michigan in the mid-1960s. To alleviate the environmental impacts of exotic and invasive fish in the Great Lakes, fisheries increased the number of Pacific salmon that would feed on rainbow smelt and alewives, according to Randy Claramunt, a DNR fisheries research biologist based in Charlevoix.

Salmon fishing outlook steady despite fewer eggs collected

By IAN K. KULLGREN
Capital News Service
LANSING — Natural resources officials are reporting record-low numbers of salmon eggs gathered at state collection sites this year, evidence that could have implications for future fishing seasons. In Manistee County, just 2,700 chinook salmon returned to the Department of Natural Resources (DNR) collection site on the Little Manistee River, down from a previous low of about 5,800 in 2010. The same is true in Traverse City, where 1,300 fish returned, a notable drop from the 1993 low of 2,300. DNR workers trap the salmon in weirs throughout the summer season, and then harvest their eggs in the fall to be bred at hatcheries across the state

The cause, wildlife officials say, stems from the perennial competition for food with invasive species in Lake Michigan. “It shines a light on how variable things are in the system,” said Edward Eisch, the DNR’s acting fish production manager.