Image by Kenrina Maidment
|White-clawed crayfish Austropotamobius pallipes - Endangered
Although this, our only native crayfish species, still occurs in many places in southern Britain, it is declining so fast that all remaining locations are of importance to its survival. White-clawed Crayfish are found under stones, rocks and in crevices of streams and rivers, and require good water quality. Between January 2018 and January 2019, the Blackdown Hills AONB ran the Culm Community Crayfish Project, the River Culm being one of two places in the Devon where the species survives. Part of a long-term initiative to safeguard white-clawed crayfish on the river and its tributaries, the project gathered information about populations of both native and non-native species of crayfish. It also raised awareness and recruited volunteers to undertake citizen science surveys. The project found the River Culm population to be under severe and imminent threat of extinction from crayfish plague, introduced by non-native Signal Crayfish Pacifastacus leniusculus. Longer term negative impacts of Signal Crayfish include degradation of the river ecosystems through invertebrate and fish predation, bioturbation (burrowing, ingestion and defecation of sediment) and riverbank erosion. The project report concludes that White-clawed Crayfish conservation action should focus on the location and establishment of ark sites using wild caught and captive bred animals, as a matter of urgency.
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The Blackdown Hills AONB will soon be starting the River Culm Community Crayfish Project, involving communities around the River Culm in learning about and looking after the white clawed crayfish. The project aims to gather important information about the fragile populations of the native white clawed crayfish, the non-native signal crayfish, and the diverse wildlife of the River Culm.
Map to show the Devon distibution of this species
Image above by Keith Hiscock
|European spiny lobster or crawfish Palinurus elephas - This lobster is largely confined in the British Isles to the extreme south-west coasts of England and Wales, and to the west coasts of Scotland and Ireland. It is found at depths of 5m or more below low water, mainly in the zone below that dominated by seaweeds. Juveniles live in holes in the reef whilst larger individuals occupy rock ledges and under overhangs. Following a population crash in the 1960s and 1970s due to overfishing, after which the species became very scarce in the SW, in 2014 there was a mass recruitment of small ones, the larvae perhaps originating in Brittany. This recruitment has continued to this day, the original cohort reaching marketable size in 2019. Now there is considerable cooperation between fishers, regulators, scientist and naturalist to try and prevent a repeat of the boom and bust fishery. A workshop in Plymouth in April 2019 brought together stakeholders to share knowledge and inform management, and to identify opportunities for collaborative research. It is possible than an increased use of tangle nets to catch this lobster may adversely impact on populations of the Yellow Staghorn Sponge Axinella dissimilis, another Devon Special Species.|