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Entries in Lake Michigan (38)

Wednesday
Mar122014

Fish Pass Through Electric Barrier

The last line of defense against Asian carp entering Lake Michigan isn’t impenetrable, according to a new report by the U.S. Army Corps of Engineers and the U.S. Fish and Wildlife Service.

Fish can pass through the electric barrier unharmed when they get caught in the wakes of barges passing through. And that’s not all. Metal barges can deplete the charge, and small fish aren’t always susceptible.

"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,” says an interim report based on laboratory and field experiments.

“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."

The Corps emphasizes that the findings are preliminary, with more work to be done with the barge community and the Coast Guard to see how the barrier can be strengthened.

“There is no evidence that Asian Carp are bypassing the barriers; nor is there any indication Asian carp are in the vicinity of the barriers,” the agency says. “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.”

Critics point out that water samples taken near the barrier and in a canal on the lake side of the barrier have tested positive for the exotic fish. Plus, poisoning of the canal in 2009 revealed an Asian carp carcass.

Read more here.

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

Friday
Feb142014

Electric Barrier Is NOT Stopping Fish

Oh, yeah! That electric barrier is going to keep Asian carp from entering Lake Michigan via a manmade connection to the Mississippi River basin.

Or maybe not.

A video obtained by the Milwaukee Journal Sentinel shows small fish swimming through the electrified water, just 35 miles downstream from Chicago’s lakeshore.

And no one said that the invaders must be adult fish.

“The only thing holding back the Asian carp at the moment is the electric barrier, but few people beyond Illinois politicians, the canal-dependent barge industry, and the Army Corps are buying the idea that the barrier is doing its job. Many worry the agency's continued confidence in this leaky, last line of defense will take a tragic toll on the Great Lakes, the world's largest freshwater system,” said the newspaper.

Thursday
Feb062014

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.)

Wednesday
Feb052014

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.

Monday
Jan272014

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.)