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Entries in invasive species (184)

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.

Friday
Jan242014

Texas Expands Requirement to Drain Boats

In an effort to slow the spread of zebra mussels through Texas fisheries, those fishing in 30 more counties will be required to drain their boats. Mostly the effort is aimed at protecting the Trinity, Brazos, Colorado, and Guadalupe river basins.

Thus far, the exotic shellfish have been found in six Texas locations, and resource managers fear they will hitchhike from contaminated waters to other lakes in livewells and bilge water, as well as on trailers and props.

Now consideration is being given to going statewide with the requirement.

Learn more here.

Wednesday
Jan152014

More Appetizing Name Sought for Snakehead

Clients catch snakeheads as well as bass with guide Steve Chaconas on the Potomac River. Click on the photo to visit his website.

“Snakeheads are considered a good eating fish but who wants to order snakehead for dinner? 

“The Charles County Commissioners invite citizens to participate in a Snakehead Naming Contest. Beginning at noon on Tuesday, Jan. 7, go here and submit ideas for a new and improved name for the snakehead fish . . .

 “The first phase of the Snakehead Naming Contest runs for 30 days from Tuesday, Jan. 7, through Thursday, Feb. 6. At the end of phase one, a panel of judges will select three entries to move forward in the contest.

 “The second phase of the Snakehead Naming Contest begins Tuesday, Feb. 18, and ends Thursday, March 20. During this time, the public will be able to vote online for one of the three selected entries. Prizes will be awarded to three individuals whose entries receive the most votes.


“The final, winning name will be sent to the Maryland Department of Natural Resources in hopes that the state will consider the name as the Snakehead’s new, ‘official’ name.”

 From Chesapeake Current