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Entries in Lake Michigan (41)


Invasive Species Threat Goes Both Ways

Mostly resource managers have been concerned about Asian carp invading the Great Lakes through a manmade connection with the Mississippi River basin. But exotics already in the lakes also could migrate out and spread into rivers throughout the Midwest, if the electric barrier separating the two systems is not 100 percent effective.

One of those is the Eurasian ruffe, a small perchlike fish that entered Lake Superior during the mid 1980s in the ballast water of European freighters. It then spread to Lakes Michigan and Huron, and, this past summer, researchers found ruffe DNA in Chicago’s Calumet Harbor.

“The Eurasian ruffe is a relatively small fish that produces a lot of eggs and reaches maturity very quickly,” said Lindsay Chadderton, Aquatic Invasive Species Director for The Nature Conservancy’s Great Lakes Project. “They feed from the bottom of the food chain, and they’re going to compete with native and introduced species dependent on the same fauna.”

On the positive side, Illinois officials emphasized that no live ruffe have been captured in the harbor. They said that the DNA could have come from a bait bucket or ballast tanks, not an actual fish.

Still, even the possibility that the ruffe could be poised to spread inland underscores how vulnerable both the lakes and the Mississippi River basin are to invasive species and the need for an effective two-way barrier, according to The Nature Conservancy and other conservation groups.

(This article appeared originally in B.A.S.S. Times.)


Asian Carp DNA Found in Lake Michigan

Lake Michigan now has joined Lake Erie as a fishery where Asian carp DNA has been discovered.

A single positive sample for silver carp was found in Sturgeon Bay this past summer, according to the Wisconsin Department of Natural Resources (DNR), which conducted the research along with the University of Notre Dame and The Nature Conservancy.

The water sample wasn’t screened for the presence of carp DNA until recently. It was collected originally in a search for evidence of Eurasian ruffe, another exotic fish species.

Is the finding cause for concern? That’s debatable. But it is reason enough to begin regular sampling of Sturgeon Bay.

“When we start talking about evidence for Asian carp in a system and the use of DNA, we talk about repeated sampling events and repeated detections,” said Chris Jerde, a Notre Dame scientist.

This latest discovery was from just one of 50 water samples taken in Sturgeon Bay and 282 total from the state’s portion of Lake Michigan.

But Jerde added that if Asian carp DNA were commonly spread by bird feces, boat hulls, and other means besides live fish, other positive samples would be noted from across the Great Lakes.

"We can talk about alternative pathways (for DNA to get into a water body), but we still have thousands of negative detections throughout the Great Lakes and we have one positive here."

DNR’s Bob Wakeman added, “It is what it is. We just need to clarify what it means.”

Despite the discovery of positive DNA in Lake Erie and even a couple of live carp over the years, no evidence has been found of a breeding population.


Indiana Moves to Reduce Pollution of Lake Michigan

Guide Dale Stroschein fights a Lake Michigan smallmouth. Photo by Robert Montgomery

Anglers, environmentalists and many others are pleased with a recent decision by the Indiana Department of Environmental Management (IDEM) to reduce pollution of Lake Michigan and its fisheries.

A stricter IDEM permit requires BP’s Whiting oil refinery, just outside Chicago, to lower its mercury discharges from 23 parts per trillion to 8.75.

“We are pleased the agency responded to our recommendation by strengthening the mercury requirements and requiring BP to submit and update its stormwater plan,” said Lyman Welch of the Alliance for the Great Lakes. “Still, we are disappointed that IDEM did not go as far as we’d hoped to protect the waters of the Great Lakes.”

At BP, meanwhile, spokesman Scott Dean said that new technologies for pollution reduction are promising.

“BP is committed to protecting Lake Michigan and we are cautiously optimistic that our recent investment in new water treatment equipment will further reduce the Whiting Refinery mercury discharge,” Dean said. “Having said that, the mercury limit in the revised permit has decreased by more than half and the refinery needs to gain experience operating the new equipment before we will know if the refinery can successfully and consistently meet this revised limit.”

The company has almost completed a $3.8 billion expansion that will make it a top processor of heavy crude oil from Canada’s tar sand deposits. Following announcement of construction in 2007, IDEM allowed BP to increase its discharge of mercury, ammonia, and suspended solids.

Public outrage over that decision convinced BP to abide by stricter standards for ammonia and dissolved solids. But Indiana allowed an exemption for mercury as the company worked on technology to scrub its waste of that pollutant.

(This article appeared originally in B.A.S.S. Times.)


Electric Barrier Isn't Keeping Fish Out of Lake Michigan


You know that expensive electric barrier erected to keep carp out of the Great Lakes?

Uh, well, that isn’t working so well, according to a new report from the Army Corps of Engineers. That’s because small fish can ride in on the flow behind barges crossing the barrier.

In a new report, the Corps says the following:

"Initial findings indicate that vessel-induced residual flows can trap fish and transport them beyond the electrical barriers, and that certain barge configurations may impact barrier electric field strength. Additionally, the preliminary (sonar camera) findings identified the potential for small fish (between 2-4 inches in length) to pass the barrier array in large groups, or schools."

Crews dropped in a camera 10 minutes at a time to see what was happening. In 61 percent of the 72 samples, they saw entire schools of fish, “not believed to be Asian carp,” swimming through.

But not to worry:

"There is no evidence that Asian carp are bypassing the barriers. Nor is there any indication that Asian carp are in the vicinity of the barriers," states the report. "The closest adult Asian carp found in the Illinois River are about 55 miles from Lake Michigan, and no small Asian carp have been observed closer than 131 miles from Lake Michigan."

So . . . it’s okay that we are spending millions of dollars to maintain a barrier that doesn’t work because, well, it doesn’t have to work because the Corps says the invaders are far, far away and don’t pose a threat.

Gee, that makes me feel so much better. I have to wonder, though, if the Corps is as competent at estimating the threat as it is at defending against it. 


Prescription Drugs Contaminating Lake Michigan

Prescription drugs and other chemicals are contaminating Lake Michigan as far as two miles from the Milwaukee sewage discharges, according to researchers. That’s an unpleasant surprise for those who had theorized that water was diluting the pollutants to non-threatening levels.

With 14 chemicals found at levels of “medium or high ecological risk,” scientists don’t know what effect they are having on fish and other aquatic life. But they are concerned.

“You’re not going to see fish die-offs but subtle changes in how the fish eat and socialize that can have a big impact down the road,” said Dana Kolpin, a research hydrologist for the U.S. Geological Survey. “With behavior changes and endocrine disruption, reproduction and survival problems may not rear their ugly head for generations.”

The chemicals’ ability to travel and remain at relatively high concentrations means that aquatic life is exposed, so there could be “some serious near-shore impacts,” added Rebecca Klaper, an associate professor at the University of Wisconsin-Milwaukee and senior author of the study published in the journal Chemosphere.

Of the 27 chemicals found, the most prevalent were caffeine, metformin (an antidiabetic drug), sulfamethoxazole (antibiotic), and triclosan, an antibacterial and antifungal compound found in soaps and other consumer products. The latter is known to be toxic to algae and can act as a hormone disruptor in fish.

The real problem, though, is the witch’s brew created by the contaminants blending together in the fishery. “It’s going to be hard to ease out which of these compounds may do harm,” Kolpin said.

Klaper added that the Milwaukee Metropolitan Sewerage District does a better job than other plants at removing many compounds. But its facilities are just not equipped to handle the volume.

“For example, we found quite a bit of caffeine in the lake, and they’re removing about 90 percent of the caffeine that comes in for treatment. They can’t remove everything.”

Capturing these pollutants is a challenge not just for Milwaukee’s treatment plants but for those across the country, according to Kevin Shafer, executive director of the Milwaukee Metropolitan Sewerage District.

“At the time wastewater treatment plants were developed, these compounds were just not an issue,” he said.

(This article appeared originally in B.A.S.S. Times.)