Crayfish plague hits Suffolk river


Scientists from CEFAS have confirmed the presence of a deadly disease affecting crayfish which has killed thousands of the crustaceans in Suffolk.

Crayfish plague, which is caused by a fungal pathogen called Aphanomyces astaci, has killed thousands of Turkish crayfish in the River Waveney between Bungay and Lowestoft in Suffolk, East Anglia.

Experts at the Centre for Environment, Fisheries and Aquaculture Science's Weymouth laboratory confirmed the identity of the disease today.

The disease was first introduced into the UK with the North American Signal crayfish when commercial crayfish farmers imported the species to England in the 1970s.

While the fungus does not kill Signal crayfish, they act as carriers and the disease is lethal to to the UK's native White-clawed crayfish, Austropotamobius pallipes, and other introduced European species, such as the Turkish crayfish, Astacus leptodactylus.

Crayfish plagueBirgit Oidtmann, an internationally recognised expert on crayfish plague who works at CEFAS told Practical Fishkeeping: "The most likely route of introduction of crayfish plague into the River Waveney is via the introduction of North American crayfish.

"In the past, there have been cases of deliberate introductions of North American crayfish into other river systems, but introductions may also occur by accidental co-transport of North American crayfish during stocking events.

"A less likely, but also possible, route is through contaminated fish, fishing gear, boats or other damp equipment."

The current outbreaks is described by CEFAS as a "mixed blessing." The species it has attacked is a non-native one and is likely to be wiped out as a result of the outbreak, however, it could also help spread Crayfish plague into nearby waters, which places native White-clawed crayfish at risk.

Crayfish in the UKSeveral species of crayfish are found in UK freshwaters, however, only a single species, Austropotamobius pallipes, is native.

It is considered globally threatened by Crayfish plague and is a protected species in the UK and covered by a UK Biodiversity Action Plan.

To protect the species, DEFRA introduced legislation in the late 1990s which makes it illegal to keep any species other than the tropical Red-clawed crayfish, Cherax quadricarinatus. (See: Blue lobster, Cherax quadricarinatus)

However, despite the legislation unscrupulous or uninformed dealers continue to flout the law by stocking and selling species that are illegal in the UK.