Lamprey killing program underway

[Spiel]

Lamprey killing program underway - Local fishermen cope with slimy predators

 

 

May 14, 2008

SHANNON QUESNEL / elliotlakestandard.ca

 

 

Sea lampreys are a pain for commercial fishermen and a literal thorn in the side of fish.

 

The only weapon against the tube-shaped bloodsuckers is the Sea Lamprey Management Program (SLMP), which started its lampricide initiative last month. The program’s goal is to kill as many Great Lakes sea lampreys as possible.

 

The payoff is the preservation of not only native fish, such as lake trout, but also the billion-dollar commercial and sport fishing industries operating in the Great Lakes.

 

One fisherman who is benefiting from the program is Blind River’s David Carlson. The Carlson family has been making a living on Lake Huron since the early 1900s. The business is now called Carlson Brothers.

 

Carlson says while Lake Huron’s lamprey population has been controlled for several years the lake still has high numbers of the predator compared to other Great Lakes.

 

 

Tough pests

 

SLMP division manager Robert Young says there are about 150,000 lamprey spawners living in Lake Huron. Young works out of the SLMP’s Sault Ste. Marie office.

 

To keep the number at 150,000 or lower, lampricide has been applied every year to select rivers and streams. For Lake Huron in 2008, lampricide will be applied to Sauble River, Serpent River, Mississagi River, Lauzon Creek and Aux Sables River (Spanish River).

 

The lampricides are applied to rivers and streams by one of two roving team of workers, from eight to 16 people in size.

 

Young says the lampricide is dripped or pumped into the water through a spreader hose that stretches across the stream. These mobile labs will also monitor the lampricide’s concentration. A single river’s treatment will take a day or two at most.

 

“We are trying to have a concentration to kill lampreys for nine to 12 hours,” Young explains.

 

The lampricide chemical is lethal to lampreys, but harmless to other fish when applied properly. Some fish might be affected if they are weak from spawning activities or by disease or pollution. Baitfish or another species confined artificially can also be harmed because of stress caused by crowding or handling.

 

There are drinking water concerns. Municipalities, individuals and farms that use the streams where the lampricide is applied will be notified to suspend stream use for a period of time.

 

Young says this lampricide has been tested by Health Canada and by the Environmental Protection Agency in the U.S.

 

Without the lampricide and techniques such as releasing sterile male lampreys and barriers, lampreys can cause great harm to Great Lakes fish stocks.

 

“What we are really doing is preventing damage,” says Young. “Our program is preventing millions of larvae that (would) get out into Lake Huron.”

 

Young says the Mississagi River alone produces five to six million lamprey larvae a year.

 

 

Ancient predator

 

Great Lakes sea lampreys are an invasive species.

 

Before being introduced to the world’s largest collection of fresh water lakes, the lives of sea lampreys were similar to salmon. Lampreys are born in rivers and streams and when they are larger they migrate to the Atlantic Ocean to feed. The prey of ocean-bound sea lampreys are tunas, sharks and other very large fish. Lampreys are nothing more than a pest to these big predators, but to lake trout the 90-centimetre (36-inch) parasites are killing machines.

 

“If they feed on a five-pound lake trout the lamprey is able to extract enough blood from that fish to actually kill it,” says Young.

 

Pickerel and other fish do feed on lampreys, but only when the parasites are small and living in a stream. Young has not seen evidence this predation is cutting down sea lamprey numbers.

 

Young says sea lampreys have four life stages, with the third being the most dangerous to Great Lakes fish.

 

“The spawning lampreys are the terminal of the life cycle.”

 

They produce eggs that hatch into larvae, which grow in streams for four to six years and they turn into juvenile lampreys.

 

The animal is most dangerous at this stage. It will leave the river and swim out into Lake Huron.

 

When a juvenile lamprey finds a target it applies its sucker-like mouth to the fish’s side. Most fish cannot shake the lamprey off or twist around to bite the predator.

 

Using teeth and tongue the lamprey scrapes away scales and skin to get to the meat. It then drinks blood and other fluids when the host fish bleeds. A single feeding will either kill the host or leave it weak. Most fish will not survive multiple feedings.

 

When the lamprey is full it detaches and looks for new prey.

 

Young says a single lamprey can kill four to eight kilograms (nine to 18 pounds) of fish during its juvenile stage. After reaching maximum size a lamprey returns to the streams and rivers to lay eggs.

 

 

Enlisting

 

Carlson has seen the damage a lamprey does to a fish. Its bite can leave a hole the size of a quarter.

 

These days though lamprey are not as bad as they were.

 

“Their percentage changes. Some days you hardly see any markings (bites) and some days you see quite a bit.”

 

Lampreys that are pulled off caught fish are not thrown back into the water, he says.

 

“We keep ‘em. And that is where the sea lamprey Sault (office) will clue you in. They’ve had programs with us for years where we do some tagging and marking and the lamprey will go into solution.

 

“At other times they ask us to bring in lampreys live and then we just put them into holding tanks. They will do different scientific experiments with them or use them for displays at conventions.”

 

As for what a wounded fish is worth to him it depends on the damage and what the fish is used for.

 

“It depends on where it goes. You get selective. If you were selling to somebody who was smoking it, well, then it is not as critical.

 

“It (also) depends how lampreys have been attached. If they just latched themselves on and there is just surface discolouring that’s a lot different than a great big lamprey that stays on (and puts) a big hole through the side.”

[fishindevil]

I think the lampreys are increasing in numbers,myself and other salmon fishermen have all noticed an increase in fish with new or old lamprey marks on them in the last few years,man i wish they could killl them all !!!!!