Mitten Crab Alert
Mitten crabs may pose a serious threat to the freshwater, estuarine and
marine ecosystems and economy of the West Coast. First discovered
in San Francisco Bay in 1992, they spread to the Sacramento and
San Joaquin rivers where massive migrations clog fish screens and
hamper water delivery. One mitten crab was found in the Columbia
River in 1997. Mitten crab burrows weaken levees and increase bank
erosion. They can eat salmon, trout, and sturgeon eggs and may threaten
successful spawning. Juvenile crabs also damage rice fields. These
crabs can carry the oriental lung fluke, a threat to human health. Native
to Asia, mitten crabs live in freshwater but migrate to saltwater to
reproduce and are easy to identify because they have hairy claws (other
identification traits on back of card). Often, recreational anglers or
commercial fishermen are the first to discover the mitten crab because
they commonly steal bait from anglers or are caught in commercial nets.
Your help is vital to report new sightings and to prevent their spread.
if you catch a mitten crab,
• Do not throw it back alive!
• Preserve it in rubbing alcohol or freeze it.
• Note the precise location where the crab was found.
• Contact your local natural resource management agency:
In Alaska, call the Fish and Wildlife Service (907-262-9863);
in British Columbia, call Fisheries and Oceans (604-666-6529);
in Washington, call the WA Department of Fish and Wildlife
(360-902-2200); in Oregon, call the OR Invasive Species Hotline
(866-468-2337, toll free); in Califomia, call the CA Mitten Crab
Hotline (888-321-8913, toll free).
REMINDER: Know the rules!
Mitten crab specimens are needed to confirm sightings, but many jurisdictions have different possession and transport mles. Contact your local natural resources agency for instructions. Never transport live mitten crab.
2001 PacifIc States Marine Fisheries Commission