Wildlife

Invasive Crayfish Hits Texas

Australian redclaw discovered in Rio Grande Valley; negative effects on local species feared.

Texas has a new invader. Several Australian redclaw crayfish (Cherax quadricarinatus) have been collected this year from Rio Grande Valley sites in their first known appearance in the state.

Researchers from the University of Texas — Rio Grande Valley found the invasive crayfish at an apartment complex pond in the Brownsville area. Texas Parks and Wildlife Department aquatic biologist Archis Grubh surveyed numerous sites in the area during the summer and found three additional Australian redclaw crayfish between the apartment pond and a nearby resaca two miles away.

“We don’t know when these invasive crayfish were first introduced or how far they have spread, but we do know they can have a negative effect on local species and biodiversity,” Grubh says. “Spreading the word about this invasive species and reporting sightings to TPWD can help us better understand where it is distributed so we can potentially take steps to help prevent its spread.”

The species reproduces prolifically, with females brooding up to five times a year at 1,000 eggs per clutch. Australian redclaw crayfish grow rapidly and can reach their maximum size of 2 pounds in less than a year. These large crayfish significantly alter habitat and vegetation, competitively exclude native crayfish and impact native fish communities by direct predation. It takes a lot of eating to grow that large.

Sightings of Australian redclaw crayfish should be reported to TPWD by emailing photos and location information to [email protected].