Sea
Lamprey Control in the Great Lakes - Truely One of the Most Complex
and Astounding Stories in the History of North American Fisheries Management
Historically,
Lakes Huron, Michigan, and Superior were the source of large, high quality
cold water fish for markets of the Midwest and east coast. Lake trout
alone accounted for an average annual commercial catch of 7000 tons
in the 1940s. The season closed in 1962 with the lake trout population
collapse brought on by the invasion of parasitic sea lampreys
introduced to the Upper Great Lakes through shipping canals.
The sea lamprey
is a predatory fish that attaches to host fish and feeds on the blood
and body fluids. A single sea lamprey kills 40 or more pounds of fish
in its life as a parasite. It is native to the Atlantic Ocean and existed
throughout the St. Lawrence Waterway and Lake Erie but was prevented
from moving up into the Upper Great Lakes by Niagara Falls. The canal
system used to provide boat transport through the eastern states and
ultimately, the construction of the Welland Canal in the late 1800s
to provide a shipping route bypass around Niagara Falls, allowed sea
lamprey to gain access to the Great Lakes. By the mid-1900s sea lamprey
had colonized each of the the Upper Great Lakes.
The
U.S. Fish and Wildlife
Service (USFWS), acting as an agent through the
Great Lakes Fishery Commission,
implemented a massive chemical control effort in the 1950's and by the
early 1960's had reduced the abundance of sea lampreys by 90 percent.
This effort paved the way for recovery of self-sustaining populations
of native lake trout in portions of the Upper Great Lakes. See
Aquatic Species Conservation Poster.
While total
elimination of sea lamprey populations from the Great Lakes in unlikely,
continued chemical treatments along with new technologies and techniques
such as mechanical and electrical barriers, sterilization of adult males,
and application of phermones to attract lampreys to traps, is leading
to increasingly healthier fish populations and an economic powerhouse
fueled by the resulting recreational fishery. Sea lamprey control will
continue and become more important as lake trout restoration activities
expand in the Upper Great Lakes.
The Great
Lakes Fishery Commission contracts and funds sea lamprey management
in the Great Lakes. The Canadian
Department of Fisheries and Oceans conducts sea lamprey management
in Canadian waters of the Great Lakes and has partnered with the U.S.
Fish and Wildlife Service on large projects.
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