Adult Lampreys
 |
| GLFC, 1985 |
Passive migration of the landlocked species begins in late Oct. continues through the winter until the following April or May. The parasitic phase of the sea lamprey lasts approx. 14-15 months. It appears that no fish is safe from sea lamprey attack. In one study, in Lake Cayuga, of 74 species of freshwater fish inhabiting the lake, none were immune from lamprey predation (Hardisty and Potter, 1971). Furthermore, in spite of preferences with respect to certain fish, lamprey will readily change hosts. In descending order of frequency of attacks, lamprey parasitized: splake, carp, sucker, bullhead, rainbow trout and bass. In the accompanying figure, we see newly transformed lamprey parasitizing brook trout in an aquarium.
Once the lamprey invaded the upper Great Lakes, the lake trout suffered most severely, however, once that species was virtually eliminated from the L. Huron and L. Michigan, other fish stocks were seriously depleted including rainbow trout, whitefish and burbot (and yellow perch in L. Huron).
 |
| GLFC, 1985 |
With the marine distribution of this species, off the Atlantic coast, wounds and scars from lamprey attacks are commonly found on sei whales (Halliday, 1991). Furthermore, sea lamprey have been captured attached to basking sharks, swordfish and bluefin tuna (Halliday, 1991). In this figure, we see the damage done to fish, notice the scars left from the oral disc. For more information see parasitic behaviour.
Swimming
When sea lamprey are disturbed, they are capable of swimming at great speeds, but only over short distances. When the current is strong, sea lamprey move along edges of streams to pass through difficult stretches. They will expend great amounts of energy over short periods of time and then rest by attaching themselves to rocks by their oral disc. When they encounter barriers, they move back and forward along the surface of the barrier and seldom can they jump more than two feet (Hardisty and Potter, 1971).
Spawning Habitat
One factor that determines the time of migration upstream is temperature of the water. Upstream migration begins in April. The spawning habitat includes gravel 0.9-5.2 cm in diameter and the presence of sand or fine materials. The water velocity required is 0.5 to 1.5 m/s in one direction over the nest. Majority of spawning events occur at depths of 30-64 cm. The water temperature required for successful development of eggs is 15.6-21.2 (celcius), optimum (18). (Hardisty and Potter, 1971).
Return to Sea Lamprey Home Page