SEA LAMPREY

(Petromyzon marinus)

The Sea Lamprey is a primitive fish native to coastal watersheds of the Atlantic Ocean, but has become invasive since it was introduced to the Great Lakes. This eel-like fish spends part of its life cycle in the ocean, but can also survive in freshwater.

ORIGIN
They are native in the Atlantic coast from Labrador to the Gulf of Mexico and Florida; but have become landlocked in the Great Lakes and several New York lakes. Sea lampreys are also found along the Atlantic coast of Europe and Mediterranean Sea.

HABITAT
Sea lampreys are generally marine, but ascend to freshwater rivers to spawn.

IDENTIFICATION
Sea lampreys resemble eels, but unlike eels, they are parasites of large fish. Sea lampreys are members of an ancient family of jawless fish that were around before the time of the dinosaurs. They grow to 30-50 cm (12-20 inches) long. They have dark- brown to black backs and light- yellow to pale- brown bellies. Look for a feathery fin from their midsection down and under the tail. Their sucking mouth is circular with circular rows of teeth. They have large reddish eyes.

Sucking mouth of Lamprey

SPREAD
Construction and improvements of the Welland and Erie Canals (between Lake Ontario and Lake Erie) around 1921 allowed sea lampreys to get from the Atlantic Ocean and the St. Lawrence Seaway through the canal to the rest of the Great Lakes. Sea lampreys can lay over 100,000 eggs when spawning, many more than the native lamprey species such as the Ohio, silver and brook lampreys.

IMPACT
Sea lampreys feed by sinking their disc-shaped mouth full of teeth into a fish. They hold fast to the sides of their victims as they feed on blood and body fluids. Large fish are better able to survive a lamprey attack with just a circular scar left on their sides; however, small fish may die immediately from the attack or from a wound infection.

Lamprey attached to Lake Trout

When they first arrived on the Great Lakes scene, they killed large numbers of sport fish. People began to notice fewer large fish and scars on others. Lampreys preyed on whitefish, lake trout, and chub populations in Lake Superior and Lake Michigan. What followed was a collapse in these commercial fisheries during the 1940s and 1950s, particularly in lakes Huron and Michigan, and in eastern Lake Superior.

PREVENTION AND CONTROL
There are several current methods to control the spread and population growth of sea lampreys.

• Lampricide- a chemical (commonly known as TFM) added to the water that is effective in killing young sea lampreys.
• Sterilization- by sterilizing competitive males and placing them in the water, they will spawn with females but conception will not occur.
• Electric barriers- the barriers keep lampreys from traveling upstream to nesting habitat.
• Dams- building dams that are small enough for fish to leap over them, but too high for lampreys to pass keeps the sea lamprey from traveling upstream to nest.

FOR MORE INFORMATION ON THE ATLANTIC SEA LAMPREY

• Sea Lamprey: The Battle Continues
• The Five Lampreys of Lake Michigan
• Alien Profile: Sea Lamprey
• Sea Lamprey Fast Facts
• Sea Lamprey: A Great Lakes Invader

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