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Lake Michigan Committee: News Release



LAKE MICHIGAN COMMITTEE

For Immediate Release	
April 21, 1997

Contact: Marc Gaden
313-662-3209 ext. 14
mgaden@glfc.org
http://www.glfc.org	

FISHERY OFFICIALS CONCERNED ABOUT 
INCREASED SEA LAMPREY WOUNDING IN LAKE MICHIGAN

LAKE MICHIGAN COMMITTEE NOTES PRECIPITOUS DECLINE IN YELLOW PERCH


ANN ARBOR, MI — Fishery managers from Michigan, Indiana, Illinois,
Wisconsin, and the Chippewa-Ottawa Treaty Fishery Management Authority met
recently in Ann Arbor, Michigan and expressed concern over increases in sea
lamprey and declines in yellow perch in Lake Michigan.  The sea lamprey, a
fish native to the Atlantic ocean, invaded the Great Lakes in the early
part of this century and wreaked havoc on the fishery, driving many
commercial and sport fish stocks to the brink of extinction.  Sea lampreys,
though once under control, are again causing significant damage to the Lake
Michigan and Lake Huron fisheries due to high levels of lamprey production
in the St. Marys River.  During the meeting, the Lake Michigan Committee
supported a proposal to begin sea lamprey treatments in the St. Marys
River. The committee also noted that severe reductions in yellow perch
abundance show no sign of improvement after several years of decline in the
western and southern portions of Lake Michigan and after minimal
recruitment in Michigan waters.

SEA LAMPREY WOUNDING IN LAKE MICHIGAN

	Lake Michigan fishery managers reported that sea lamprey wounding rates in
Lake Michigan are at a significantly high level.  Said committee member Tom
Trudeau of the Illinois Department of Natural Resources:  "Lake Michigan's
sea lamprey problems have worsened considerably over the past ten years. 
Not only are wounding rates significant in the northern part of Lake
Michigan, but wounding rates appear to be increasing in the southern part
of the lake as well.  In the Julians Reef area in Illinois waters, for
instance, we may be seeing an increasing trend in sea lamprey wounding
rates."  Sea lamprey wounding rates in Lake Michigan—particularly in the
northern part of the lake and in open-lake lake trout spawning sites—are
approaching the wounding rates seen before lamprey control began in the
1950s, prior to the collapse of the fishery. 

	The cause of the increase in Lake Michigan lampreys is primarily due to
lamprey migration from the St. Marys River, the connecting channel between
lakes Superior and Huron.  A joint U.S.-Canadian sea lamprey control
program has reduced sea lamprey abundance by 90% in most areas of the Great
Lakes and has allowed fishery agencies to stock fish and implement fishery
restoration measures.  The St. Marys River is the lone exception to this
remarkable sea lamprey suppression record.  The river produces more
lampreys than all of the other Great Lakes combined; sea lamprey control in
the St. Marys River has been impossible traditionally because of its large
size and tremendous flow volume. 

	During its meeting, the Lake Michigan Committee agreed with the Lake Huron
Committee that sea lamprey control in the St. Marys River is a top
priority.   To combat the problem, the Lake Michigan Committee concurred
with a proposal to combine the granular Bayer lampricide with trapping and
the Sterile-Male-Release-Technique to achieve an 85% reduction in Lake
Michigan and Lake Huron sea lampreys.  This proposal was developed by sea
lamprey control biologists and research scientists working under the
direction of the Great Lakes Fishery Commission.

 	"The continued trend of high sea lamprey wounding rates in Lake Michigan
is intolerable," said Lake Michigan Committee Chairman John Trimberger of
the Michigan Department of Natural Resources.  "The high wounding rates we
are experiencing are contrary to fish community objectives and indicate
that we must address this problem if our efforts to restore and maintain
native species are to be successful and if we want our native and
introduced sport stocking programs to be meaningful.  Reducing the flow of
sea lampreys from the St. Marys River will be a major factor in reducing
sea lamprey predation in Lake Michigan."

YELLOW PERCH

	The Lake Michigan Technical Committee reported that yellow perch abundance
in Lake Michigan continues to decline precipitously in Wisconsin, Illinois,
and Indiana waters while showing only minimal recruitment in Michigan
waters.  Significant numbers of yellow perch larvae are not surviving well
to the young-of-the-year  stage, which means that aging adult populations
are not being replaced readily by new generations of perch in Lake
Michigan.

	Scientists are not sure of the cause of the yellow perch decline, though
they do agree that the fish are not surviving to a harvestable age.  To
study the situation further, the Yellow Perch Task Group, established by
the Lake Michigan Fish Chiefs, will narrow its focus to two areas:  alewife
predation on larval perch and early perch fry mortalities.  The task group
recommended that a lakewide tagging study be conducted to investigate
yellow perch movement and homing to spawning sites.

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