Easy on the Eyes, Not So Easy on the Lake
by Jeremy Elton Jacquot, Los Angeles on 07.23.07
While more visually appealing than murky or dark waters, clear blue waters may not necessarily reflect a lake's true cleanliness and health. Lake Erie, for example, was once considered to be a "dead lake" in the late 1960s because it was so badly polluted. It now has increasingly clear and pristine waters due in great part to the contributions of the zebra mussel, an incredibly destructive invasive species that entered the Great Lakes system almost 2 decades ago.
It has been able to accomplish this through one simple mechanism: kill every other living organism underwater. As a filter feeder, the zebra mussel draws in a large quantity of water each day through its incurrent siphon (close to 1 liter) and consumes all the organic matter and plankton it catches with its gills. Though this helps leave the water clear, it also robs other organisms of a potential food source.
"The impact that the public is seeing is with that increased water clarity, but they're not equating that with the impact zebra mussels have had on the lakes' ecosystems," said Francine MacDonald of the Ontario Federation of Anglers and Hunters. In addition to forcing fish and other aquatic wildlife from their natural habitats, the mussels create a razor sharp carpet on the lake's floor that makes it practically unwalkable.
More worrying is the fact that zebra mussels have a knack for quickly spreading from one body of water to another, often jumping into streams, rivers and inland lakes across the region. In their larvae stage, they are virtually invisible and can peacefully drift through large tracts of water for a considerable period of time.
They were first able to spread to Lake Erie and the rest of the Great Lakes from Lake St. Clair by attaching themselves to the hulls of boats. The only way to stop this invasive species from taking over new bodies of water and annihilating all present life is through prevention, as MacDonald notes: "With zebra mussels there is no control, so prevention is the key way to stop them or prevent their spread to new water bodies."
Via ::The Tribune: Clear blue waters in the Great Lakes; Experts says this is not necessarily a good thing (newspaper)
See also: ::Chinese Water: A Picture is Worth... [Updated], ::Burn it Where You Buy it to Stop Invasive Species
UPDATE: We replaced the original picture as JiltedCitizen pointed out it wasn't exactly appropriate.
Image courtesy of dwstucke
Couldn't you at least not use a tropical picture for the great lakes? They are also spread by ballast water, MI is trying to pass legislation on that but half of the lakes are International waters.
I believe that is a photo of longpoint on the Ontario side of Lake Erie.
http://www.on.ec.gc.ca/wildlife/factsheets/images/longpointaerial.jpg
They changed it...It was some tropical tree and the ocean.
The flow of exotics is a natural part of evolution and biolgocial change over time. The earthworm is an exotic to the US. We can't hold ecosystems static. Of course, we want to act to protect endangered species and economically important resources, but its very much the art of the possible. With carp and zebra mussels, we should be looking into minimizing their adverse impact, not turning back the clock.
Are Zebra mussels edible? Perhaps we ought to eat 'em.
The adverse impact is that they are not supposed to be here. If it were a purely evolutionary migration something would develop to control the population. As it is nothing will develop fast enough before they kill all other life and clog up all intakes and drainage pipes.
Gobies eat Zebra Mussels, unfortunately they also eat native fish eggs and young and reproduce like crazy. The fishermen on the Lake Ontario pier near me just throw them up on the shore to die. They are gross looking and must be gross tasting because the seagulls don't even eat them.
More info:
http://en.wikipedia.org/wiki/Goby
http://www.great-lakes.net/envt/flora-fauna/invasive/goby.html
http://www.protectyourwaters.net/hitchhikers/fish_round_goby.php
Perhaps zebra mussels would make good fertilizer? Scoop 'em out and dump 'em on the fields! Probably stink a bit, and the shells would be pesky, but if I remember the beasts are quite small.
I am glad some people are raising the evolution perspective. I understand concern people have. But I am kind of shocked and dismayed by the almost dominionist arrogance of the nativists on this blog. Evolution is a process that supercedes human agency. This is by definition. I am not arguing preventive measures should be avoided. It should just should be pointed out that they often don't serve the purpose they intend and often quite the contrary because of evolutionary process. For example on the Zebra Mussel, there is an evolutionary limit to its success. If that particular species wipes out all biological life as the poster is suggesting then the Zebra Mussel is sowing the seeds of its own destruction. Eventually an equilibrium will be achieved and a predator species will come along, perhaps even humans as others suggest in this comment thread. This is evolution in its purest form. I am not saying this is a particularly pleasing result to humans, but evolution doesn't care what humans think. As Richard Dawkins says we are merely survival machines for our genes.
Another example of human misunderstanding is the Hart Mountain reserve and Pronghorn Sheep in Eastern Oregon. For years is was thought that coyotes were the cause of diminishing pronghorn sheep herds and so a specific coyote prevention program was put in place. But the real factor was abolishing cattle grazing in the reserve and leaving the coyotes alone. This allowed the ecosystem to bouce back, the foliage to thrive, and the sheep and coyote populations found an equilibrium where both could be successful.
Zebra mussels cement themselves to rocks. They are very small and sharp. I have cut my feet a few times on them while swimming in lake Michigan. Harvesting them is not an option unless you want to dive with a sharp knife or dredge the bottom of the lake.
I've heard they taste awful. Most freshwater mussels do. The mussels we eat at restaurants are a salt water variety.
Ya, but there's been a huge increase in the bird populations around the lakes... at least in bird species that can eat the mussels. Obviously though, there are huge problems associated w/ having multiple bird species thriving off of just one food source.