Sunday, December 10, 2006

Sea Lamprey-A Prodigal Native Son?

Sea Lamprey-A Prodigal Native Son?
Genetic research suggests the sea lamprey is indigenous to Lake Ontario


Barbara Branca, Communications Manager, New York Sea Grant

John Waldman:
Department of Biology
Queens College of the City University of New York

Isaac Wirgin: or 845-731-3548
Nelson Institute of Environmental Medicine
NYU Medical Center

STONY BROOK, NY, August 31, 2004- A research team, with some funding from New York Sea Grant, suggests that the parasitic sea lamprey, a species usually considered invasive with its immense economic impact on commercially and recreationally important fishes of the Great Lakes, may be native to Lake Ontario.

In research described in the recent Transactions of the American Fisheries Society, John Waldman of Queens College of the City University of New York, and Isaac Wirgin, Cheryl Grunwald and Nirmal Roy of New York University's Department of Environmental Medicine analyzed mitochondrial DNA of sea lampreys (Petromyzon marinus) from 10 locations along Great Lakes and Atlantic coasts.

"This is a most interesting study that offers additional evidence for the theory of an indigenous sea lamprey population in Lake Ontario," says Dave MacNeill, New York Sea Grant Fisheries Specialist located at SUNY College at Oswego along Lake Ontario's eastern shore.

Genetic comparisons were made of groups of lampreys along hypothesized colonization pathways. Pronounced differences in genetic frequency patterns between lampreys collected along the rivers of the Atlantic Coast and those in the Lake Ontario watershed, together with arguments against the viability of lamprey colonization via the Erie Canal, strongly support the idea of natural lamprey colonization by one of at least three hypothesized pathways following the retreat of the glaciers.

The sea lamprey lives throughout the North Atlantic Ocean, spawning in rivers in Europe and North America, and parasitizing a wide variety of fish. Each of the Great Lakes with the exception of Lake Ontario has documented dates of observed invasion of the sea lamprey in the twentieth century. The first sighting of the species in Lake Ontario was 1835, 12 years after the completion of the Erie Canal. Some investigators have concluded that the canal was the means of entry of the fish into the lake. But some have held a contrary view that sea lampreys are indigenous.

This research team's genetic evidence suggests that the sea lamprey may have colonized Lake Ontario right after the Pleistocene by one of three hypothetical pathways: the Delaware-Susquehanna drainage, the Hudson-Mohawk system or the St. Lawrence River, the lake's present outlet.

Throughout the Great Lakes, parasitic sea lampreys cause a loss of revenue in both the commercial and recreational fishing industries. Numerous ongoing programs to eradicate or at least deplete their numbers are in effect. Their lack of homing behavior (failure to return to rivers in which they spawned) has sometimes exacerbated eradication methodologies. However, if sea lampreys are indigenous to Lake Ontario and therefore part of the lake's ecosystem, management policies aimed toward intense suppression might need reevalution.

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