Sea Monsters

Chautauqua Lake is being invaded! These invaders do not come armed with guns and knives. They don’t even have arms. Their takeover is not violent, but it is destructive.

The invaders, which include a variety of plants and animals, are non-native species. That is, they are species that do not occur naturally in or around Chautauqua Lake. When they get into the lake, they find an environment without their natural predators, parasites, pathogens or competitors. In their own home environment, these factors would have limited their population. Unfortunately, for Chautauqua Lake’s native species (but fortunately for the invaders), the lake provides the invasive species with plenty of resources to grow and reproduce. As a result, the invaders proliferate and crowd out the native species and destroy the lake’s ecosystem.

The invaders don’t arrive under their own power or by their own intention. Humans help. Some invaders are plants or animals that people deliberately transported to the lake because they were thought to be attractive or useful. Most, however, are stowaways on boats, vehicles, animals, commercial goods, produce and even clothing.

The recent rise of fast freighters has greatly accelerated the introduction of non-native species to the Great Lakes area. These freighters take on ballast water in ports overseas to stabilize the ship for the ocean crossing, water that no doubt includes aquatic plants and animals. The ship arrives in the Great Lakes and empties the water into the lake along with its population of potential invaders. The Great Lakes are less polluted than they used to be, which is good for native species, but it is also good for invasive species. The invaders are more likely to survive because the trip is relatively short, due to the speedier ships, and the water is healthy when they arrive.

If an aquatic invader makes its way to the Great Lakes, it is quite likely to show up in Chautauqua Lake. Chautauqua Lake is not connected to the Great Lakes by any waterway, yet the invaders do make the journey, with help. They come over the hill from Lake Erie to Chautauqua Lake on trailers carrying boats.

Although there are many invaders in our midst, two of the most notorious are the Zebra Mussel and Eurasian Watermilfoil.

Zebra mussels were first discovered in the Great Lakes in 1988. It is supposed that they traveled in the ballast water of ships coming from the Zebra Mussel’s native home, the Caspian Sea. These tiny mussels are very prolific. A single female Zebra Mussel can produce up to one million eggs per year. That means, with the large population of Zebra Mussels inhabiting Chautauqua Lake, trillions of eggs hatch into microscopic larvae, called veligers. Trillions of veligers settle on and attach to any firm surface intake pipes from water treatment systems, boats, docks and even the shells of native mussels using byssal threads. Not only do Zebra mussels commandeer lake space, they plunder the lake’s food supply as well. Zebra Mussels are extremely efficient at filtering water. A single mussel will draw in and expel a quart of water a day, filtering all the plankton out of it. It consumes what plankton it needs to sustain itself and makes a pseudofeces out of what it does not digest. Pseudofeces fall to the lake bottom, removing an essential link of the aquatic food chain for many native species.

Eurasian Watermilfoil is the main character in Chautauqua Lake’s “weed problem.” As its name suggests it is originally from Europe and Asia. Once commonly sold as an aquarium plant, it is speculated to have turned up in American waterways in the late 1800s and documented to have been here by 1940. Most of us who play in Chautauqua Lake have encountered its thick underwater strands of tangled stems. Not only is Eurasian Watermilfoil annoying to humans, but the thick floating canopy can crowd out important native plants. It reproduces by stem fragmentation and underground runners. A single segment of stem and leaves cut off by a boat propeller can quickly take root and form a whole new colony.

Unfortunately, once an invasive species establishes itself, it is almost impossible to eradicate. We can only hope to manage Chautauqua Lake’s current invasive species. But there are ways to prevent new invaders from arriving. When you leave another body of water and come to Chautauqua Lake, be especially vigilant about inspecting any aquatic equipment (boats, fishing nets, bait buckets, etc.) for any suspicious organisms and remove them. Live wells and bilges should be dried out and/or disinfected with bleach. Let’s help keep sea monsters in the realm of myths and legends and out of our lake!

The Chautauqua Watershed Conservancy is a local nonprofit organization that is dedicated to preserving and enhancing the water quality, scenic beauty and ecological health of the lakes, streams, wetlands and watersheds of the Chautauqua region. For more information, call 664-2166 or visit www.chautauquawatershed.org or www.facebook.com/chautauquawatershed.