[Photo: Shawn Sitar with the Michigan Department of Natural Resources].
A growing number of Lake Superior trout dubbed “zombie” fish for their emaciated appearance has scientific minds puzzled.
Siscowet lake trout — which reside in the darkest and most pressurized depths — are most affected, according to the Great Lakes Fisheries Commission, which is coordinating research to determine the cause and find solutions. The fish appear increasingly starved, while some have additional spinal abnormalities.
The zombie fish are concerning more than scientists. Ontario Out of Doors Senior Editor Gord Ellis, whose home waters are Superior, typically fishes the north shore and targets trout in less than 100 feet of water, where lamprey wounds are commonly found on lakers.
"Every angler who fishes Lake Superior should be concerned that the deep water siscowet lake trout seem to be struggling,” he said, adding he hopes research will find answers.
“Siscowet are an important part of the ecosystem, but also quite possibly the canary in the coal mine on the lake."
There may also be hidden factors at play, suggested Ontario Federation of Anglers & Hunters (OFAH) Fisheries Biologist Adam Weir. “It’s difficult to interpret reports of emaciated lake trout in Lake Superior when researchers have not yet identified a cause or confirmed whether there is a broader issue,” he said. “While several possible explanations are under investigation, including food web changes, disease, lamprey interactions, and contaminant exposure such as mercury, it is still too early to draw conclusions and there may be other interacting factors not yet considered.”
