Rises_in_Lakes_Superior and Erie being addressed aggressively
Ann Arbor, Michigan - The Great Lakes Fishery Commission today reported that populations
of the invasive sea lamprey remain at near-historic lows in Lakes Michigan, Huron,
and Ontario, though the destructive, parasitic pest has increased in abundance in
Lakes Superior and Erie. Sea lamprey population increases in Lakes Superior and
Erie were greater compared to the other lakes even as abundances are generally holding
steady. The Commission and its partners believe sea lamprey populations across the
basin may be rebounding from the harsh winters of 2013/2014 and 2014/2015, though
other factors such as prey availability and warmer water temperature may be factors
as well. In response to the increased numbers, the Commission and its partners have
ratcheted up control in problem areas and heightened monitoring and assessment so
that future control efforts will be targeted effectively.
Sea lampreys remain a constant battle in the Great Lakes, as the invader, native
to the Atlantic Ocean, reproduces in the lakes and destroys many species of fish.
Today, the Great Lakes fishery is worth $7 billion annually to the people of Canada
and the United States. Without sea lamprey control, the fishery would suffer significant
ecological and economic harm. Before control, sea lampreys killed an estimated 103
million pounds (47 million kilograms) of fish per year. Today, because of control,
sea lampreys kill less than 10 million pounds (4.5 million kilograms) of fish per
The sea lamprey is one of the worst human-caused ecological disasters ever inflicted
upon the Great Lakes. Sea lampreys invaded through shipping canals and, by 1939,
were present throughout the system. They attach to Great Lakes fish with a tooth-filled,
suction cup mouth and file a hole through the fish's scales and skin with a razor-sharp
tongue. The average sea lamprey will kill up to 40 pounds (18 kg) of fish during
its parasitic stage. Sea lampreys prefer trout, salmon, whitefish, and sturgeon,
but they also attack smaller fish like walleye and perch.
Given the tremendous damage sea lampreys caused, Canada and the United States, through
the 1954 Convention on Great Lakes Fisheries, charged the Great Lakes Fishery Commission
with implementing sea lamprey control and research; the commission partners with
Fisheries and Oceans Canada, the US Fish and Wildlife Service, and the US Geological
Survey to deliver the program. Sea lamprey control consists of several techniques
including lampricides, barriers, and traps. The commission also is experimenting
with chemosensory cues as a way to disrupt spawning behavior. For more information,
"Sea lampreys are the scourge of the Great Lakes and must be controlled," said David
Ullrich, chair of the Great Lakes Fishery Commission. "Without sea lamprey control,
the Great Lakes fishery would be laid to waste by the voracious predator. Unfortunately,
sea lampreys are here to stay. Fortunately, we can control them effectively such
that we lose only a small amount of fish to lamprey compared to the hundred million
pounds lost each year prior to our control program. Sea lamprey control is worth
the effort and is the foundation of the fishery we enjoy today. "
Ullrich added: "Today's news about sea lamprey abundances provides reason for optimism
but also is a caution against complacency. Although we saw increases in Lakes Superior
and Erie, we still are at or near historic lows in sea lamprey abundances in the
remaining Great Lakes. The success of the program is due to extraordinary work carried
out by our control partners. Sea lampreys are resilient beasts and we cannot let
up on our control effort. We will always work aggressively to reach our sea lamprey
suppression targets in all lakes."
"Overall, the sea lamprey control program has been a tremendous success," said Robert
Hecky, the Commission's vice-chairman. "The control program provides fish a chance
to survive long enough to spawn, be caught by humans, or live a natural life. It
also allows agencies to restore stressed species and maintain thriving sport, commercial,
and tribal fisheries."
By lake, the latest sea lamprey status is as follows:
LAKE ONTARIO: Consistent treatment effort on Lake Ontario for the past 25
years has contributed to keeping lamprey numbers at or near target and historic
lows. Sources to watch include the Niagara River, but this connecting channel currently
has a low larval sea lamprey abundance.
LAKE MICHIGAN: Heightened and targeted treatment strategies in Lake Michigan
employed since 2012, and biennial treatment of the Manistique River since 2003,
have contributed to historic lows in abundances; targeted treatment was applied
again in 2017. Lake Michigan likely benefits from treatments in the northern portion
of Lake Huron (e.g. St. Marys River). Sources of concern include tributaries that
are difficult to treat in the northern and eastern portions of the lake.
LAKE HURON: Heightened and targeted treatment strategies in Lake Huron employed
since 2010, including two large-scale treatments of the St. Marys River, have contributed
to historic lows in lamprey abundances; another round of targeted treatment is scheduled
for 2018. Lake Huron likely benefits from the treatment of tributaries in the northern
portion of Lake Michigan (e.g. Manistique River). Sources to watch include the St.
Marys River and tributaries that are difficult to treat in the northern portions
of the lake.
LAKE SUPERIOR: A targeted treatment strategy was implemented in 2016, and
the impact of these efforts will not be seen until 2018. The reasons for the relatively
high abundances in Lake Superior are not fully apparent. Sources to watch include
lentic areas of the Chippewa, Nipigon, Gravel, and Batchawana rivers. Treatments
have recently occurred in these systems. The Bad River has also been treated recently,
however, some concerns remain that treatment effectiveness may not have been ideal
for this system. The St. Louis River, which has undergone significant restoration
as an area of concern through the Great Lakes Water Quality Agreement, looms as
a potential sea lamprey producer that would be difficult to treat.
LAKE ERIE: The reasons for the relatively high abundances in Lake Erie are
not apparent. Sources to watch include the St. Clair River, the only known source
of sea lamprey not treated regularly. Intensive larval survey efforts recently conducted
to identify previously undetected populations did not reveal any untreated tributaries.
Preliminary acoustic telemetry results indicate that adult sea lamprey are exploring
tributaries not currently treated, however, that does not necessarily mean the tributaries
are producing sea lamprey. Larval assessment surveys will be conducted to look for
recruitment in these tributaries.
*  Sea lamprey abundances are reported as 3-year averages. For more information about
methodology and to see lake-specific graphs, visit www.glfc.org/status.php. *
The Great Lakes Fishery Commission is an international organization established
by the United States and Canada through the 1954 Convention on Great Lakes Fisheries.
The Commission has the responsibility to support fisheries research, control the
invasive sea lamprey in the Great Lakes, and facilitate implementation of A Joint
Strategic Plan for Management of Great Lakes Fisheries, a provincial, state, and
tribal fisheries management agreement. www.glfc.org