A study of the dynamics of a natural population of the freshwater crayfish, Austropotamobius pallipes |
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Authors: | J M BREWIS K BOWLER |
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Institution: | Department of Zoology, University of Durham |
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Abstract: | SUMMARY. 1. Population size, survival and recruitment were estimated from mark—recapture data at frequent intervals. 2. Two types of mortality were identified: (1) moult-associated—an intense but short duration mortality, and (2) overwinter mortality, which operated at a lower estimated weekly rate but over some 30 weeks. 3. Population size reached a mid-summer peak as recruitment into the catchable size classes occurred. Thereafter numbers declined slowly to the end of the growth season, followed by an overwinter decline of some 50% of total. 4. Annual production was estimated at 196.5 kg wet wt ha?1 in 1977, 116.8 kg wet wt ha?1 in 1978 and 87.79 kg wet wt ha?1 in 1979. |
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