Just when you though it was safe to go in the water.
Sea Lamprey: The Battle Continues
Chicago (Global Adventures): Scuba divers exploring the Great Lakes are now warned to pressure wash all gear before using it in other bodies of water to avoid spreading the sea lamprey, an invasive species that destroys native lake trout populations by attaching themselves and drawing blood and nutrients from the fish. Victims typically die from excessive blood loss or infection.
“Invasive species are deadly to the ecosystem and costly to control,” said Elizabeth Latenser of Chicago’s Shedd Aquarium. “Without natural predators or a niche in the food chain, invasive species are able to out-compete native fish for food and habitat.”
Sea lamprey (Petromyzon marinus) is a predaceous, eel-like fish native to the coastal regions of both sides of the Atlantic Ocean. The species is native to the inland Finger Lakes and Lake Champlain in New York and Vermont. It is not clear whether it is native to Lake Ontario, where it was first noticed in the 1830s, or whether it was introduced through the Erie Canal, which opened in 1825.
Most scientists believe that sea lamprey entered Lake Erie through the Welland Canal about 1921. It did not take long to spread to Lake Michigan, Lake Huron, and Lake Superior. In the 1940s and 1950s, they contributed to the collapse of the lake trout, whitefish, and chub fisheries. Annual catches of lake trout in Lakes Huron and Superior dropped from 15 million pounds to 300,000 pounds by the early 1960s. While the population has been reduced by 90 percent in most areas due to chemical control, the St. Marys River is still considered a “hot zone.”
The life cycle of sea lampreys is anadromous, like that of salmon. The young are born in inland rivers, live in the ocean as adults, and return to the rivers to breed. Young emerge from the egg as larvae, blind and toothless, and live that way for 3 to 7 years, buried in mud and filter-feeding. Once they have grown to a certain length, they metamorphosize into their parasitic form, after which they migrate to the sea. They become sexually mature after several years, stop feeding, and return to freshwater rivers and streams to spawn.
Through public outreach, educational programs and the invasive species exhibit in the Local Waters Gallery, the Shedd Aquarium encourages the public, including scuba divers, to take action and help to prevent the spread of invasive species.
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