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Fishes of Idaho



Lampreys (Petromyzonids)

Pacific lamprey (Lampetra tridentata)


Pacific lamprey belong to a very unique class of fish known as agnaths, or "jawless fishes". Unlike any other Idaho fish, they are a predacious parasite that feeds off of live fish. Lampreys have a circular suction-cup mouth that is lined with hook-like teeth. lamprey moutha.jpg (9088 bytes)Once attached to a prey fish, lampreys use their tooth-lined tongue to rasp a hole through the skin of their prey. They are then able to feed upon blood and tissue, maintaining the flow by injecting an anti-coagulant to keep the victims blood from clotting. Perhaps equally amazing is that these eel-like fish are anadromous. Just as salmon and steelhead do, Pacific lampreys migrate from streams and rivers in Idaho to the Pacific Ocean before returning to spawn. Although they are not particularly strong swimmers, they are able to overcome tremendous natural and artificial obstacles such as waterfalls and dams by using their mouth to cling to the substrate. Although not well-documented, the number of lampreys in Idaho is known to have declined substantially in recent decades.

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