Invasive Australian redclaw crayfish found in Texas; species can carry crayfish plague

Researchers found multiple species in Brownsville area, unknown when they were introduced

Multiple Australian Redclaw Crayfish were found in the Brownsville area earlier this year, the Texas Parks and Wildlife Department said. (TPWD)

Researchers in the Rio Grande Valley discovered an invasive crayfish that can have a negative effect on native species and can also carry the crayfish plague.

Multiple Australian redclaw crayfish were found in the Brownsville area earlier this year, marking the first known cases in Texas, the Texas Parks and Wildlife Department announced on Thursday.

California is the only other state in the U.S. that has detected the crayfish.

TPWD said that researchers from the University of Texas Rio Grande Valley collected three Australian redclaw crayfish in January and February from an apartment complex pond that connects to a resaca, or channel.

Biologists surveyed different sites in the area and found three more Australian redclaw crayfish nearby.

“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,” TPWD aquatic biologist Dr. Archis Grubh said in a news release. “Spreading the word about this invasive species and reporting sightings to TPWD can help us better understand where it is distributed and potentially take steps to help prevent its spread.”

Both males and females were collected, “so the potential for reproduction is a concern in these waterbodies,” TPWD said.

Females can produce up to five times a year at 1,000 eggs per clutch. In a year, one crayfish can grow to its maximum size of two inches.

TPWD said the invasive species can impact native species by excluding them and altering habitat and vegetation.

They can also carry parasites and diseases, including the crayfish plague.

The crayfish plague is a disease that’s caused when the pathogen Aphanomyces astaci infects the host, causing death.

The pathogen may kill “individuals of a population within a few days,” according to a scientific journal in the National Library of Medicine.

TPWD said that while it’s unclear when the crayfish were introduced to the South Texas waters, it may have been caused by someone dumping them.

However, the Australian redclaw crayfish and all other members of the crayfish Family Parastacidae are prohibited to be sold and possessed in Texas. They cannot be sold at aquariums in Texas.

“Release of aquarium life is unfortunately a key means by which invasive species such as these crayfish are introduced,” Monica McGarrity, the TPWD Senior Scientist for Aquatic Invasive Species, said in the release. “Well-meaning, uninformed aquarium owners sometimes release their pets thinking they’re doing the best thing for them, but if they do survive, they can become invasive and harm the native aquatic species and ecosystem. Aquarium owners should research alternatives to aquarium dumping and help prevent introductions of the next invasive species.”

If you spot an Australian redclaw crayfish, you are urged to email photos and location information to aquaticinvasives@tpwd.texas.gov.

They are identifiable by their large head, large left claw with a red patch, and four ridges on the top of the head.

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Rebecca Salinas joined KSAT in the fall of 2019. Her skills include content management, engagement and reporting.