The sea lamprey is a toothed, jawless fish but nature’s plastic surgeon has lent it some deadly features creating devastation in our Great Lakes. Indigenous to the Atlantic Ocean, it likely entered into great lakes during early 20th century via some carriers like Welland Canal.
A Parasitic Nightmare
The sea lamprey unique form of predation is to attach itself onto a host fish, like lake trout and whitefish by cupping it mouth and sucking. It then uses its sharp teeth to rasp a hole in the skin of the fish and feed on their blood or bodily fluids. This parasitic feeding may weaken and eventually kill the host fish, causing mass declines in parasites.
The Great Lakes Invasion
The introduction of sea lampreys had catastrophic effects on the fishery in the Great Lakes. Prior to the introduction of sea lampreys, the Great Lakes were abundant with valuable fishes such as lake trout, whitefish and sturgeon. But the lampreys proved to be too successful at feeding and quickly killed off those populations.
Control Efforts
In response to the sea lamprey invasion, a multifaceted control program has been developed by scientists and fisheries managers that consists of:
Chemical Control -Use of lampricides, specifically TFM, to kill lamprey larvae in streams and rivers.
Future Operations Presented in Five Alternatives Physical Barriers Construction of barriers (locks, walls) to prevent lamprey from emigrating upstream to spawning grounds;
Sterile Male Release: Releasing sterile male lampreys to mate with female, but not create offspring.
Traps Based On Pheromones: It is based upon the attraction of lamprey towards pheromone which then traps them.Although these controls have been successful in decreasing sea lamprey populations in the Great Lakes, they must be maintained to prevent rebound and safeguard important fish resources.
The sea lamprey is a living example of the havoc an invasive species can wreak on an ecosystem and local economies alike. With a better understanding of the biology and behaviour of this parasitic fish, we can establish management plans that are able to keep it in check so as not to upset the delicate fauna balance for aquatic ecosystems.