Parasite could help save salmon

  • "PUNK-ROCK FISH": The suctorial disc of the Pacific lamprey

    Donna Allard
  Endangered salmon may get help from a strange source: Blood-sucking, eel-like fish called lampreys.

On Jan. 28 a coalition of environmental groups petitioned the U.S. Fish and Wildlife Service to protect four species of lamprey under the Endangered Species Act. Two of the species are parasitic, latching onto salmon and other ocean-going fish to feed on blood.

“They are kind of punk-rock fish,” says Jeff Miller of the Center for Biological Diversity. “But they are important in the ecology of the stream.”

Ironically, the parasite could be an ace-in-the hole for efforts to protect the rivers and estuaries where salmon live. A 2001 court ruling undercut those efforts by concluding that salmon reared in hatcheries are the same as wild fish. The ruling, which inflates salmon numbers, could knock some species off the endangered list — meaning less protection for the rivers where they spawn (HCN, 10/8/01: Coho salmon lose federal protection). But saving the lamprey could mean protection for salmon streams from California to British Columbia.

The environmental coalition asserts that its push to protect lamprey is not a back-door attempt to save salmon. Studies show that lamprey have been declining for at least 20 years. River dredging, pollution and other kinds of habitat degradation limit the fish’s ability to migrate and reproduce, and dams hinder their spawning — lamprey lack the strength to swim up ladders designed for salmon.