The 'Pritchard Trap' survey method for crayfish - data from deployment time experiment and comparison with Triple Drawdown (TDD)

The 'Pritchard Trap' (PT) is a novel quantitative survey method for crayfish. Here, we trialled the PT in rocky headwater streams in North Yorkshire, England along an invasion gradient for signal crayfish from well-established sites to mixed populations of signal crayfish and native white-clawed crayfish. A deployment time experiment was undertaken to determine the minimum deployment time. Data for deployment intervals of 1, 2, 4, 7 and 10 days are presented. The PTs were also compared to the Triple Drawdown (TDD) technique to allow for a robust evaluation of PT sampling accuracy in representing crayfish densities and population structure. Data from TDDs and PTs are presented.