A
National Success Story: Lake Trout Conservation in the Upper Great Lakes
Lake
trout are native to the Great Lakes and historically provided
a large commercial fishery. Wild
lake trout populations nearly vanished in the Upper Great Lakes (Lakes
Michigan, Huron, and Superior) in the 1940's and 1950's after years
of over fishing and losses from parasitic sea
lamprey. Hatchery stocking was initiated in efforts to stop the
decline of this valuable resource. The development and initiation of
effective control of sea lamprey in the 1960's resulted in increased
survival of stocked lake trout. Currently, the 2000 Consent Decree (U.S.
vs. MI) - which regulates tribal and state lake trout harvest in the
1836 treaty waters to prevent excess harvest - specifically identifies
increased emphasis on lake trout rehabilitation and will boost lake
trout restoration efforts (view
poster pdf). The Decree Agencies are required to increase efforts
for lake trout assessment, data analysis, and modeling to protect the
stocks while allowing the execution of sport and commercial fisheries.
Lake
trout restoration is coordinated by the Great
Lakes Fishery Commission (est. 1955) and the U.S. Fish and Wildlife
Service plays a key role, along with other federal, provincial, state,
and tribal natural resource agencies. Lake trout restoration is all
about a multi-diciplinary team involving critical elements of the Service's
Great Lakes Fishery Program - National Fish Hatcheries, the Fish Health
Center, Sea Lamprey Management Offices and Fishery Resources Offices.
A major and critical role
of the National Fish Hatchery system in the Great Lakes / Big Rivers
Region is to manage and maintain various strains of lake trout broodstock
as a source of eggs and fry, produce and rear fingerlings and yearlings,
and transfer lake trout to offshore sites for stocking into the Great
Lakes. The Fish Health Center assesses the health of hatcheries and
hatchery stocks and contributes to disease free fish. Sea lamprey management
is necessary to curb the effects of this invader on lake trout restoration
to allow survival of stocked lake trout and Fishery Resources Offices
assist with lake trout restoration plan development, coordinate research
and assessment projects, and assist with assessment of the lake trout
stocking program. All components are coordinated in a process to bring
about lake trout restoration.
Many
factors limit achievement of rehabilitation goals. Currently, mortality
from sources such as fishing and sea lamprey predation is the major
limiting factor for lake trout rehabilitation in Lakes Michigan and
Huron. Some recent changes that are expected to reduce this mortaility
include replacement of approximately 12-14 million feet of gill nets
from Lakes Michigan and Huron with non-lethal impoundment gear under
the 2000 Consent Decree, and a large chemical treatment of the St. Marys
River (thought to be the single largest producer of sea lamprey in the
Great Lakes system) that will greatly reduce the number of sea lampreys
in the Upper Great Lakes. It is hoped that these two events will provide
a "kickstart" to Lakes Michigan and Huron and initiate recovery
similar to that observed in Lake Superior in recent years. Additional
limitations include an inadequate number of lake trout available for
stocking all the habitat available in order to achieve abundance goals,
and the degradation of spawning habitat due to non-natives including
zebra mussel invasion and predation on eggs from alewife and gobies.
After
decades of restoration work, self-sustaining populations of lake trout
have been established in Lake Superior. Lakes Michigan and Huron are
showing signs of recruitment but research continues to identify major
limiting factors affecting lake trout restoration in these two lakes.The
Service continues to lead lake trout restoration efforts with strong
support from our partners. Recent accomplishments include maintaining
6 genetically diverse strains of brood stock, producing
millions of eggs for stocking and production programs, stocking over
40 offshore reefs with approximately 3,800,000 marked yearling lake
trout, leading a multi-agency sampling effort to determine the effectiveness
of lake trout stockings, recovering data from thousands of coded wire
tags, leading a cooperative sampling effort to determine the limitations
of stocking success, maintaining the Great Lakes Stocking Database,
and providing written reports on lake trout restoration progress.
Field Offices Involved
with Lake Trout Restoration
Iron
River National Fish Hatchery, WI | Jordan
River National Fish Hatchery, MI
Pendills Creek/Sullivan
Creek National Fish Hatchery, MI | Genoa
National Fish Hatchery, WI
La Crosse Fish Health Center,
WI | Marquette
Biological Station, MI
Ludington Biological Station,
MI | Alpena
Fishery Resources Office, MI
Ashland
Fishery Resources Office, WI | Green
Bay Fishery Resources Office, WI
Links to More Information
