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WMEAC: The ticking clock on invasive species in the Great Lakes

• Jan 19, 2018 at 4:00 PM

As a young man, my dad took my brother and I out on Lake Michigan for a charter fishing trip. It’s a memory I cherish, and there are a lot of reasons I worry about being able to relive that memory with my father, and with my own family as I grow older.

However, there’s the looming problem of invasive species that puts this $7 billion Great Lakes fishing industry, that employs more than 75,000 people (about 10,000 more than tech-giant Google) at risk.

The commercial and recreational fishery of the Great Lakes has been under attack by invasive species before, by the sea lamprey, zebra and quagga mussels, and alewives, each irreversibly changing the environment. Now a new scourge is posed to invade Lake Michigan. What could we lose to the Asian carp?

According to the Great Lakes Fishery Commission, sea lamprey were introduced to Lake Michigan in 1936. At the time, 15 million pounds of lake trout were harvested from the Great Lakes every year. While it’s difficult to blame a single cause in such a complicated ecosystem, over the next 25 years the sea lamprey thrived, and the fish harvest dwindled to 2 percent of its previous amount.

"They were knocking the stuffing out of the fishery," said Marc Gaden, communications director for the GLFC.

Of the fish that were still harvested, as much as 85 percent of them had wounds from feeding sea lamprey. Luckily, a selective pesticide was discovered that has been used since 1957 to successfully control lamprey populations, allowing the fishery to recover.

"I was catching 15-30 (lamprey) a year — now you might catch four or five," said Bill Winowiecki. He’s the vice president of the Michigan Charter Boat Association and has been fishing in the Great Lakes water basin for more than 50 years.

If applications of this pesticide ever stopped, the invasive lamprey would ravage the fishery once again.

There are currently about 180 known non-native species in the Great Lakes, of which only two have been controlled through chemical applications and seeding predator fish.

Unfortunately, these methods aren’t available for other invasive species. Zebra and quagga mussels have been an issue for water intakes and yachters, but have also decimated the base of the Great Lakes food web, competing with native species for the food they filter out of the water. Alewives, another invasive species, are kept in check by the stocking of the popular sportfish Chinook salmon, but as a result of the incredible rate of mussel propagation, fewer alewives can be supported, and fewer salmon fed by them.

Fortunately, the mussels’ methods of propagation and movement has made their spread to Michigan rivers and streams glacially slow, despite their prolific spread through the Great Lakes themselves.

However, Asian carp have no such weakness. Two of the four species have reached within 50 miles of Lake Michigan. These fish feed on plankton, like mussels and alewives. They eat as much as 20 percent of their own body weight each day as an adult, can grow to weigh up to 100 pounds, and lay as many as 1.9 million eggs each year, even more than a zebra mussel.

"They're going to do more damage to our inland fisheries than they probably will to Lake Michigan because there's nothing out there for them to eat," Winowiecki said.

As “bottom-up” filter feeders, Asian carp are mostly interested in the areas of the water basin not already cleaned by the mussels. And once they’re here, there will be no getting rid of them.

"If you wanted to kill Asian carp, which has been done twice on the Chicago canal, you have to just blast the canal with rotenone, and it kills everything there," Gaden said.

The Chicago Sanitary and Ship Canal currently has three electric barriers to prevent the movement of Asian carp north into Lake Michigan, but some fish have still been found beyond the barriers.

"As long as that's open for shipping, Asian carp are going to be inevitable," Winowiecki said.

All this is to say that the effort it takes to protect the fishing industry, to say nothing of the rest of the $62 billion economy surrounding the Great Lakes watershed, is worth protecting.

If we don’t spend the effort to establish control strategies designed to prevent the introduction of Asian carp to the Great Lakes from ever happening, we have to be prepared to spend 10 times as much to save the natural ecosystem from being overrun, and even that would be the best-case scenario.

About the writer: Josh Vissers spent childhood summers in Grand Haven. He is a senior at Grand Valley State University and currently works as the eco-journalism intern for the West Michigan Environmental Action Council.

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