Nature conservationists fear an invasion of local river systems after exotic freshwater crayfish were stolen from a Free State breeder this week.
Provincial ichthyologist Pierre de Villiers said on Friday especially one of the two stolen species, the Cherax Destructor, was very aggressive. If it should land in local freshwater systems, it might attack and eat local species.
The Destructor, imported from Australia, might also eat local fish eggs and small larvae and compete for space with indigenous shrimps and crayfish, De Villiers said.
The species was known for digging deep holes into dam walls and river embankments, which might weaken these structures.
Mystery was still surrounding the theft of around 400 crayfish from the breeding tanks of Herman Reinach, well-known Bloemfontein orthodontist. Reinach said he discovered the theft on Wednesday. It must have happened some time since last Monday, when a previous count was done. It occurred inside the building in which the breeding tanks were housed, behind locked doors and an electric fence, Reinach said.
He is the only South African with a permit from conservation authorities to breed and trade in the Cherax Destructor and Cherax Albitus, also imported from Australia.
He must adhere to very strict measures to contain the crayfish in his tanks and prevent them from escaping into local freshwater systems. It is feared that the thief might not realise the ecological importance of this.
Chris Louw, from the Free State department of tourism, economic and environmental affairs, appealed on Friday to the public for information to help their investigation. He said police, that was leading the investigation, had offered
Restaurant and petshop owners were asked to be on the lookout for the crayfish, whether dead or alive. They were little red and green animals, the size of prawns. Anyone with information was asked to call Inspector Smit on (051) 507-6243 or 082-966-9942. – Sapa