Dry out fishing gear prevent parasites.
Anglers asked to let fishing gear dry to help curb spread of parasite
Anglers on local lakes are being asked to let their lines, nets and other gear dry completely between fishing expeditions to prevent the spread of a parasite that a Queen's University researcher fears is taking over Ontario's lakes.
Biology professor Dr. Shelley Arnott heads a team that has been researching the spread of the spiny water flea, a tiny predator that has made its way into more than 100 North American lakes after coming here in the ballast water of an ocean-going ship from Europe or Asia.
While her research is still being done, she and her students have found that the plankton on which lake fish feed has been reduced by 70 per cent in the lakes where water fleas have colonized.
The fleas either eat the plankton directly or force it below the surface into colder, darker waters where the invasive and fast-breeding fleas cannot survive, but where it is also less available as a food source to other fish.
The end result is that it is reducing the food available to native lake fish, such as the lake herring, which feed on the microscopic plankton near the surface.
That is, in turn, reducing the population of sport fish, such as trout, which feed on the smaller fish.
"The introduction of water fleas is having a huge impact on the flow of energy in these lake ecosystems," said Arnott.
"It shows how an invasive species can disrupt the food webs of freshwater lakes by diverting energy and nutrients away from native organisms."
The water fleas were found the Great Lakes in the mid-1980s and were likely brought here by tankers and other commercial ships that discharged ballast water into the Great Lakes .
They then migrated to inland lakes as a result of anglers inadvertently transferring the tiny eggs on contaminated fishing lines, boat hulls, live wells, anchor ropes and other surfaces on which the eggs could survive.
Arnott's research has found that if the lines and surfaces are allowed to dry completely, something that takes as little as 30 minutes in summer weather, the water flea eggs cannot survive.
Arnott is urging boaters to spread out their gear to allow it all to dry before moving from lake to lake in order to stop the spread of the tiny predator.
"It's such a simple thing for the general public to do, and yet it could make a big difference in the way that our lake ecosystems function," she said.
Arnott and her students are still studying how such a tiny predator could have such a massive impact, but she says there is no question that that is what it is doing, based on studies of lakes where the parasite is known to have taken up residence.
"It's pretty dramatic," she said, noting the massive loss of the microscopic zooplankton in the lakes where the water fleas have colonized.
"We're not sure what effect is it actually having on the habitat yet, but it certainly does change the ecosystem."
At about a centimetre long, the fully-grown water flea is visible to the naked eye and looks something like a shrimp, with a long spiny tail that gives it its name and a large black eye.
While small fish can swallow the flea, its spiny tail acts like a fish hook when they do and prevents the flea from being swallowed as fish literally choke the parasite back up.
