http://ipraudio.interlochen.org/FishRecover_WEB.mp3
It might surprise you to hear that some native fish are doing really well in one of the Great Lakes. For years now, we’ve heard bad news about the lakes. Most of it has to do with invasive species getting into the lakes and wrecking the food web. One writer memorably called it a slow-moving underwater wildfire.The recent swing in the other direction is so dramatic scientists are a bit puzzled and can’t explain what’s happening.
Regime shift?
Not long ago researchers were using the word “collapse” to explain what had happened to the food web in Lake Huron. There just weren’t many fish at all. That’s why it’s surprising that some native fish are now recovering very quickly, particularly a small one called bloater. Stephen Riley does annual trawls for the U.S. Geological Survey.
“We’re not used to seeing this many fish in one haul," he says. "We’ve got catches now of bloater in certain places that we’ve never seen ever in our records.”
These surveys have been going on for almost 40 years in Lake Huron. Prey fish are important to monitor because they’re the food for the big fish, like walleye and salmon, fish people like to catch. (Bloater, by the way, is a fish most people call a chub. If you have seen one, it was probably smoked for you to eat.)
Bloater is not the only native fish doing well in Lake Huron. Another you've likely have never heard of is slimy sculpin.
Lake trout are coming back to life too. Lake trout used to be popular to eat and commercial fishing actually helped wipe them out of the Great Lakes. Stephen Riley says there wasn’t much hope for lake trout in Lake Huron until recently. Now, the fish are reproducing across the lake.
“It’s another example of something that’s telling us that maybe the lake is going back into a state where it can support these native fish.”
Riley says the changes in Lake Huron are dramatic enough to wonder if the ecosystem is undergoing some kind of permanent change. Biologists refer to this as a regime shift.
An unanticipated and perplexing recovery
Whatever you call it you wouldn’t say it was expected. Chuck Madenjian surveys Lake Michigan for prey fish. He says a consensus was starting to form that these lakes could never bounce back. Madenjian says the amount of prey fish being found in Lake Huron now flies in the face of that.
“There’s promise of hitting levels we even saw in the eighties," he says. "Most people have already dismissed the idea that you could get prey fish populations to that level or even close to it.”
Unfortunately, there are no signs of a dramatic recovery in Lake Michigan and that highlights the fact that scientists can’t fully explain what is happening or why. Lakes Michigan and Huron are really one lake, so it’s unclear why fish would do well on one side of the straits but not the other.
That difference might suggest the news is not as good in Lake Huron as it seems. That is Mark Ebener’s view. He works for the tribal agency called the Chippewa Ottawa Resource Authority. Ebener says some years are better than others to catch fish in bottom trawl nets, and he’s not sure catching lots of fish in some parts of the lake is always a good reflection of what is happening lake wide.
“I just think that the increases that we’re seeing aren’t quite as big as the data would suggest,” he contends.
Still, Ebener thinks the recovery in Lake Huron is real. He even thinks Lake Michigan is on the same path, but that it’s moving more slowly. He’s says tribal fishermen that fish out of Epoufette in the Upper Peninsula now catch a fish called herring or cisco.
“They tell me when they were kids in the fifties, their dad used to catch lots of cisco off Epoufette in the fall,” says Ebener. “They haven’t seen cisco there since they were kids.”
Ebener says the cisco are really sensitive to invasive species and other problems; a “wimpy” fish he says. So if herring are turning up, it’s a sign that Lake Michigan too is moving in the right direction.
All this is not to say the Great Lakes will ever be what they were, but he thinks the goal of more stability, with a variety of fish reproducing naturally, is becoming a reality.