Sea Lampreys and Their

Invasion of the Laurentian Great Lakes

Petromyzon marinus

Native to the Atlantic Ocean

Jawless, large sucking disk with teeth for a mouth

Are vertebrates but have cartilaginous bone structures only.

Bore into fish and suck blood and body fluids

Specifically devastating to trout populations in great lakes.

Wound caused by Sea Lamprey

It is estimated that 40-60% of lake trout are killed from sea lamprey attacks because of the loss of blood and bodily fluids.

In Ontario, they build nests around June 4-21, when waters are around 18-23 degrees Celsius. Can be up to 10 females per nest. Females can lay anywhere from 43,997-101,932 eggs each. As temperature increases, so does the metamorphosis of the larvae to adult parasites. (Metamorphosis in Fish, Sylvia 2012)

http://www.fishbase.org/summary/2530

• Lampreys first seen in Lake Ontario and got there through man made shipping canals (1800s)

• Niagara Falls acted as a natural barrier keeping the sea lamprey in Lake Ontario.

• They spread into Lake Erie when the Welland Canal was built bypassing Niagara Falls allowing Sea Lampreys into the upper Great Lakes. They had completely taken over by the 1940’s http://www.seagrant.umn.edu/downloads/x106.pdf

The introduction of Sea Lamprey into the Great Lakes was the main reason for the introduction of the Great Lakes Fishery Commission in 1955.

The great lakes have supported the commercial fishing industry since the 1800’s. Producing as much as 40 million pounds of fish annually.Earning as much as 30 million dollars

per year. (Lucas, 2013 Great Lakes Fisheries: Can We Save Them?)

Devastation of Trout Populations

Lake Trout Population in lake superior in decline from overfishing, but was then destroyed by the introduction of Sea Lamprey. At the peak of the Sea Lamprey population, nearly ~85 of all large fish had lamprey wounds.

Since lake trout stopped eating ailwives, they started to explode and when they had their massive annual die off they covered beaches making them unpleasant for tourists.

http://www.umesc.usgs.gov/invasive_species/sea_lamprey/tech_assistance.html

• Research done by Great Lakes Fishery Commission suggest that the lake trout population declined earlier then suggested, and started 2 years earlier in 1943 and was much more severe then originally suggested.

• In Lake Michigan, U.S. catch fell from ~12.1 million kg to just 885 kg in 1953

• (Reassessment of the Lake Trout Population Collapse in Lake Michigan During the 1940s, Great Lakes Fishery Commission, 2002)

(Hile et al. 1951)

After the decline of the normally dominant fish species (Lake Trout), other species were able to become dominant.

The dominant species today are the Yellow Perch, Smelt, Lake Superior Herring and others (all have commercial value less than Trout) Now make up 85% of commercial fishing industry. (Lucas, 2013 Great Lakes Fisheries: Can We Save Them?)

Sea Lamprey Control

3-trifluoromethyl-4-nitrophenol (TFM) is applied to streams that contain sea lamprey larvae, and causes death by interfering with ATP production.

TFM must be applied over a span of 12 hours, any less and the larvae survive.

Sea Lampreys have been said to have been reduced by 90% since their invasion.

Although under control at the moment, they still remain a clear and present danger to the ecology of the great lakes basin.

(Clifford et al. 2012 Recovery of Larval Sea Lampreys from Short-Term Exposure to the Pesticide 3-Trifluoromethyl-4-Nitrophenol: Implications for Sea Lamprey Control in the Great Lakes)

Sea Lamprey ControlFirst thing they tried was electrical and mechanical

barriers to prevent access to spawning grounds. These proved to be expensive and hard to maintain.

More recently they have been releasing sterile male Lampreys into the Great Lakes to fool the females into thinking their eggs could be fertilized by these sterilized males thus causing them to waste their eggs. Them killing more fish is not a fear because when they get into their reproductive stage they no longer feed.

Now they are trying to catch lampreys using pheromones that attract other lampreys.

Overall, sea lamprey populations have been slashed but will never be totally wiped out from the Great Lakes.

The End