White-clawed crayfish surveys
White-clawed crayfish inhabit streams and rivers in some parts of the UK where they were formerly more widespread but are now in serious decline. In view of this species’ conservation status, and the requirement for planning authorities to take it into consideration, a white-clawed crayfish survey is likely to be recommended where rivers and streams are affected by development in areas where the white-clawed crayfish is known to be present.
White-clawed crayfish surveys are undertaken between July and October, and during April. Between November and March, crayfish activity is reduced and surveys are not so effective. Because crayfish breed during May and June, this precludes survey work in that period. Crayfish can be collected by setting funnel-shaped traps along the banks of streams. These traps are set overnight and contain bait to attract the crayfish, which are nocturnal. Other techniques include manually searching under boulders and torchlight (night viewing) surveys. A licence is required to trap this species for survey purposes.
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