TRAVERSE CITY — Emily Shaw had seen only two eastern banded killifish in the last three years, but this year she’s seen about 10.
Shaw, the education and volunteer coordinator at the Inland Seas Education Association, is excited about the increase she’s seen in the native species, as well as the decrease she’s witnessed in the invasive round goby.
“The thought process is some of these invasive species aren’t adapted to these extreme winters that we can have here in Michigan,” Shaw said. “If this is something that continues, only organisms that are native and used to temperature extremes will be able to survive.”
Inland Seas Education Association members regularly trawl the bottom of Suttons Bay and Grand Traverse Bay for fish counts. Round gobies typically make up at least 80 percent of the catch, but so far this year it’s comprised just over half, Shaw said.
It’s still early in the summer to know for sure how much the cold affected fish species, Shaw said.
Other wildlife expert cautioned against drawing too many conclusions too soon.
Round goby populations appear to have stabilized in the last few years after substantial increases since 2003, said Chuck Madenjian, a research fishery biologist at the U.S. Geological Survey Great Lakes Science Center.
“I suspect they could have gotten higher if it wasn’t for predators already out there,” Madenjian said. “I think predators will keep them in check from now on.”
Many lake fish feast on gobies, including alewife, trout, burbot and whitefish.
It’s especially hard to know exactly what factors determine round goby populations, said Gary Whelan, a program manager with the fisheries division of the Department of Natural Resources.
“There’s not a lot of great data,” Whelan said. “They’re right on the bottom and live in places that are hard to sample with lots of rocks.”