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Alaskan Brook Lamprey Introduction: There are about 40 species of lamprey that exist in the world, five of which can be found in Alaska. Lampreys are eel-like fish that have elongate, cylindrical bodies that become slender towards the tail. They have jawless, cylindrical to oval shaped mouths that are used for sucking. Lampreys are lacking paired fins and vertebrae. Lamprey species are distinguished most easily by their teeth. With some debate, the Alaskan brook lamprey is a separate species from the American brook lamprey.

Location: It is located in a few areas of Alaska, including on the Alaska and Kenai peninsulas, in the Chatanika and Chena rivers, and in a few river basins in the Northwest Territories.

Description: Lampreys are non parasitic, freshwater species that are gray-brown on the back and white underneath with a dark blotch on the second dorsal fin and a dark tail. They have blunt teeth and measure five to seven inches as adults.

Reproduction: Lampreys spawn in spring and summer in shallow areas of streams and sometimes lakes. After spending four years as ammocoetes (Larva), these lampreys metamorphose to adults in the fall and spawn the following spring. Lampreys spawn in the spring after spending several months moving to the cool, clear headwaters of streams to make their nests. Both males and females create pits by removing small rocks with their mouths and fanning smaller particles with their tails. The male and female deposit sperm and eggs, simultaneously while intertwined, into the nest. The female can release several thousand eggs, up to 100,000 for some species. Shortly after the eggs are fertilized, the adults die. It takes one to two weeks for the eggs to hatch into larval forms called ammocoetes. Ammocoetes are blind, lack sucking mouths, and can grow to about four inches. They burrow into the silt, sand or mud of shallow pools and eddies of clear streams and feed by filtering microorganisms and algae from the water. Lampreys remain at this stage for three to seven years and then during the fall, metamorphose into adults, which involve morphological and physiological changes, such as the development of a sucking mouth, eyes, and teeth.

Ecology: Lampreys are an important contributor to the food chain. The immature lamprey is an important nutrient processor. The ammocoetes are able to feed on particles that are too small for some organisms and process them into larger forms due to their reduced ability to digest materials. Filter feeding organisms, such as invertebrates, can then utilize the nutrients. Like salmon, lampreys also return nutrients to freshwater systems after they die following spawning. The decomposing body provides food to scavenging organisms and releases nutrients into the water.