# Invasive species generate gloomy reports for Lake Michigan



## Fish Eye (Mar 30, 2007)

*Invasive species generate gloomy reports for Lake Michigan*

*Published: Sunday, June 13, 2010, 7:20 AM Updated: Sunday, June 13, 2010, 1:54 AM*








*Victor Skinner | The Muskegon Chronicle *


GRAND HAVEN -- A perfect storm of invasive species in Lake Michigan continues to clarify the water to historic levels and threaten the lake's forage base from bottom and top, according to new reports from the Great Lakes Environmental Research Laboratory.

Analysis of current and historic data from Lake Michigan shows serious threats to sport fish brought on by quagga mussels, spiny water fleas and other invasive species that continue to thrive, although researchers remain uncertain how that will influence the lake's future.

Scientists with the National Oceanic and Atmospheric Administration's GLERL in Muskegon recently compiled and analyzed decades worth of Lake Michigan data that's set for publication in the Journal of Great Lakes Research this fall.

GLERL staff summarized the long term trends from the impact of invasive species at a public information session sponsored by Michigan Sea Grant in Grand Haven this week.

"The most historic changes in Lake Michigan are occurring right now because of the quagga mussels," said Gary Fahnenstiel, senior ecologist with the GLERL. "The water in Lake Michigan right now has never been clearer. The clarity in the spring in Lake Michigan is approaching the clearest water in the world."

That reality has contributed to increased blooms of cladophora algae along Lake Michigan shorelines, which, aside from producing an unsightly and foul-smelling mess, entangle mussels and fish that become a tainted food source for birds and popular sport fish. Scientists believe massive animal die-offs in Sleeping Bear Dunes National Lakeshore and other areas are the result.

The historical data indicates the mussels have gradually increased in number in recent years and continue to expand into deeper waters offshore. They're filtering an unprecedented amount of plankton and striping nutrients to the bottom of the lake, Fahnenstiel said.

What plankton is left is being increasingly consumed by top-dwelling spiny water fleas, and not by prey fish. The fleas are too big for prey fish to consume, Fahnenstiel said.

"You now have another species that directly competes with the alewives," Fahnenstiel said. "The spiny water flea makes it more difficult, more complicated."

Jay Wesley is the Department of Natural Resources and Environment manager for the state's southwest fisheries. He said the department "may have to reduce stocking again if things get bad enough."

"It means we would expect salmon populations to continue to decline," said Wesley, who presented a fisheries update at the Sea Grant event. "We may have to do something in the next few years."

The comparisons to the rapid decline in the Lake Huron salmon fishery are inevitable.

"In Lake Huron, (scientists) have found out that the spiny water flea is eating more plankton than all of the forage fish combined," said Dan O'Keefe, an educator with Michigan Sea Grant, which organized the Grand Haven event.

The GLERL study and series of Sea Grant events are drawing the attention of more sport anglers, charter boat operators and commercial fishermen, said Roger Belter, president of the Grand Haven Steelheaders fishing club.

"I think more people are aware of what's going on because of the news media and these publications," he said.

Belter said the problems with the invasive mussels and fleas have been getting worse for a while, with no solution in sight. But anglers have adapted their techniques and continue to haul in fish, though not always as much.

"I've been in the business 31 years, and it seems like every year there is a crisis in the fishing industry," Belter said. "Lampreys, gill nets, mussels and now they're talking about Asian carp getting into the lakes."


----------

