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Exploring the beautiful nature of California


California Nature: Lamprey


California is a large state, the 3rd largest in the U.S.A., and depending on where you go, can range broadly in habitat type and, also, climate. For this reason, California plays host to a huge variety of fish.

Fishes are aquatic vertebrates that have fins, gills and scales. Gills are the part of the respiratory system that provide surface area for exchanging oxygen and carbon dioxide under water. Fish are ectotherms, commonly referred to as 'cold-blooded', meaning their temperature is regulated by the temperature of their environment. They have a range of diets, being herbivores, carnivores, or omnivores. Some fish reproduce by laying eggs, while others reproduce by bearing live young.

California fish species reside in freshwater and coastal/marine waters. Freshwater fish are fishes that live at least part, if not all, of their lives in bodies of fresh water with a salinity of less than .05%. Forty-one percent of all known fish species are found in freshwater.
lamprey are eel-like fish found in California waters Lampreys are among the earliest fish (280 million years in archaeological records) and are parasitic using a sucking-disk shaped mouth with rasping teeth that wear a hole in the flesh of its victim. Found in temperate waters throughout the world, the lampreys have eel-like bodies, that  are cartilaginous, with no jaws, scales or paired fins. An adult lamprey has a circular mouth, called an oral disc, that exerts strong suction. Teeth are located on the oral disc and also on the tongue.

Lampreys use the sucker shaped mouth to attach to the prey and then use rasping teeth to bore through the skin and an anticoagulant to allow them to feed on body fluids. The lampreys created major environmental problems when canal construction allowed them to enter the great lakes. 

 Lamprey larvae (young) are toothless and blind. They burrow into sediment at the bottom of a stream where they feed on tiny organisms that they filter out of the water. After some three to eight years, the larvae change into adults. The adults die soon after spawning (laying their eggs).
The life history of river lampreys is not fully understood. River lampreys are anadromous and they live a predaceous life when in the ocean. Larval lampreys or ammocoetes probably spend the first 3-5 years within a freshwater stream. Ammocoetes burrow themselves tail-first into the soft substrate of a backwater where they feed on drifting matter such as algae and microorganisms. When the ammocoetes reach around 12 cm TL and several years of age they begin to transform into adults during the summer.

Metamorphosis takes 9-10 months, which is the longest transition of all the lampreys. Before river lampreys have completed the change they assemble at the mouth of the river, finally entering the ocean in late spring.

River lampreys are believed to spend only 3-4 months at sea where they grow rapidly by attaching to fish such as salmon and herring and feeding on muscle tissue.
California lampreys havea unique creepy look The voracious lampreys may kill the prey though feeding continues even after death. In the fall of the same year the river lampreys return to their natal streams and spawn from February to May. During the last part of their life the lampreys actually shrink up to 20% in length. Spawners dig nests or depressions in gravel where a female lays her eggs.

The first 4 to 6 years of the lampreys life are critical times. Animals that filter water and mud for food are very susceptible to pollutants in the water column and sediments. Lamprey have similar freshwater habitat requirements as do some of the Pacific salmon, therefore they have encountered similar habitat problems.

Though absolute historical population sizes of the lamprey are not known, it is clear that the fish, once a significant tribal subsistence food, have shown severe decline.  Because this species depends on muddy bottoms, backwater areas, and low gradient areas during its juvenile life stage, it is susceptible to loss of wetlands, and side channels.
 
 
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