Invasive Species: Sea Lamprey

The Latin name of the sea lamprey is Petromyzon marinus. The sea lamprey resembles an eel. They were first found in the Lake Michigan and belong to the family of 'jaw less fishes'. The larvae is approximately 6 inches in size. The size of the adult lamprey ranges from 20 to 35 inches.

Habitat
Lampreys can be found in Lake Ontario, Lake Michigan, Lake Superior, the Great Lake, the Atlantic Coast, the Mediterranean Sea, etc. They are born in the fresh water areas. On turning into adults, they go to the sea. But once its time for them to breed, they return to their place of birth, to the fresh water body.

Life Span
The life span of a lamprey can be anything between 3 to 17 years. The life cycle of a lamprey is very similar to that of a butterfly. As is the case with a caterpillar and its metamorphosis into a butterfly, the lamprey buries itself in the mud. This procedure takes around two months; normally from August to October. After a certain period they turn into parasites of Petromyzon marinus species. They return to the fresh water to breed, after which they die.

Food
In its lifespan, a lamprey is said to consume approximately more than 40 pounds of fish. It lives on commercially important fishes, big and small alike. In the larva stage, it survive on micro-organisms. A lamprey has a mouth shaped like a suction cup. It attaches itself to the body of the fish and sucks blood out of its body. It also preys on the body tissues of fish. A special type of enzyme secreted by the lamprey does not allow the blood of the fish to clot at its wounded portion. It leaves the victim, once all the blood and fluid has been sucked out of its body.

Appearance
The color of the lamprey can vary from black to brown on its back and from light yellow to dull brown on its stomach. It has about 10 to 12 rows of teeth. The innermost row of teeth has the largest teeth.

The male lamprey has two fins whereas the female lamprey has one. In the same way, there is a difference in the gills of the male and the female lamprey too. The male lamprey has seven gill slits whereas the female has two gill pores. When the lamprey is breeding, the back becomes multi-colored and the stomach turns yellow.

Procreation
The procreation starts around winter and continues till summer. A lamprey is said to carry approximately 240,000 ova. It carries stones onto the floor of the water body and lays the eggs there. After breeding it is often found dead. On observing the stomach of the dead lamprey, it has been found, it has fungal infection in its stomach. Lamprey is unable to recover from the fungal attack, and hence die.

Precautionary Measure
Since the lamprey preys on the commercial variety of fish and also disturbs the ecological balance, certain precautionary measures are implemented against it. In some of the lamprey infected areas, electric currents have been passed and at the others barricades have been erected. The success rate of these control methods is overwhelming. This activity is a joint exercise between the various Commissions in the US and Canada.

The lamprey, because of its resemblance to the eel has very deceptive looks. Like the parasitic lampreys, there are also the non-parasitic variety. Therefore, a clear distinction should be made between the harmful and the harmless ones.