Factors influencing pot catches and population estimates of the portunid crab Scylla serrataView Altmetrics View AltmetricsTools Williams, M. J. and Hill, B.J. (1982) Factors influencing pot catches and population estimates of the portunid crab Scylla serrata. Marine Biology, 71 . pp. 187-192. ISSN 0025-3162 Full text not currently attached. Access may be available via the Publisher's website or OpenAccess link. Article Link: https://doi.org/10.1007/BF00394628 AbstractCrab pots were used to sample a population of Scylla serrata (Forskal) in an estuarine area in Queensland, Australia. Pots were laid 100 m apart at fixed positions for 4 d each month for 1 yr (April 1980–June 1981). Data from recapture of tagged crabs showed that males larger than 140 mm carapace width and females larger than 150 mm had a higher capture probability than did smaller crabs; thus size-frequency distributions based on crab-pot captures are biased. Spacing trials showed that pots positioned 50 m apart fished competitively but that there was no difference in catch between those placed 100 and 200 m apart. Catch distribution indicated that the presence of a crab in a pot reduced the probability of further captures. Temperature and incidence of recently moulted crabs accounted for 66% of variation in monthly catches. Catch-per-unit-effort (CPUE) data can be used as a measure of relative abundance of adults if allowance is made for temperature and the incidence of moulting. The capture-mark-release-recapture method for making population estimates was tested but it is concluded that, because of cost and bias in collecting techniques, it cannot be recommended as a technique for studying S. serrata.
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