FILE PHOTO: A red swamp crayfish.

JOHANNESBURG - South Africa's department of environmental affairs (DEA) said on Wednesday it was working with the Free State department of economic, small business development, tourism and environmental affairs as well as local and district municipalities in the Goldfields area to eradicate and stop the spread of red swamp crayfish, an alien and highly invasive species.

It said aquatic scientist Dr. Leon Barkhuizen, acting on a tip-off from a member of the public in Welkom, had discovered a large population of the crayfish, whose scientific name is Procambarus clarkia, in a dam in the Free State Goldfields. 

The identification of the species was confirmed by Professor Linda Basson from the department of Zoology and Entomology at the University of the Free State.

"The reason for the presence of this alien and highly invasive species in the dam is not clear, but anecdotal reports indicate that it might have been released by members of the public," the DEA said.

Freshwater crayfish do not naturally occur in Africa and a large number of the species occur in Europe, America and Australia.

The red swamp crayfish, also known as the Louisiana crayfish, that was discovered in the Goldfields is indigenous to northern Mexico and south-east United States.

The species has spread throughout the world, mostly for aquaculture purposes and the pet shop trade.

In many countries the red swamp crayfish has escaped into natural environments where it has decimated indigenous crayfish species and other aquatic organisms and caused irreparable damage to aquatic systems. 

In South Africa, red swamp crayfish have been listed as prohibited freshwater invertebrates and a permit to possess them in the country may not be issued. Those found in possession of the crayfish can be fined up to R10 million and/or face a prison sentence upon conviction.

"Various meetings and onsite inspections will be done in the next coming weeks to determine the exact extent of this invasion," the DEA said.

- African News Agency (ANA)