Technical annual report 2000-01
Dept. of Regional Development, Primary Industry, Fisheries and Resources technical annual report; Department of Regional Development, Primary Industry, Fisheries and Resources technical and annual report; Reports; PublicationNT; Technical bulletin (Northern Territory. Dept. of Primary Industry and Fisheries) ; no. 295
Made available via the Publications (Legal Deposit) Act 2004 (NT).
Agriculture -- Northern Territory -- Periodicals; Fisheries -- Northern Territory -- Periodicals
Dept. of Primary Industry and Fisheries
Technical bulletin (Northern Territory. Dept. of Primary Industry and Fisheries) ; no. 295
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Technical Annual Report 2000/01 277 project. The project, titled Methods to Estimate Abundance and Habitat for Northern Australian Mud Crab (Scylla serrata), aims to firstly map critical mud crab habitat using remote sensing technology and then estimate the abundance of animals per unit of habitat, resulting in an estimate of stock size. The work was due to start in January 2001. As part of the ongoing Fishery Monitoring Program, biological data is recorded from the commercial catch on a monthly basis. This included carapace width, sex, stage of maturity, moult stage and weight from 100 animals from each of the four most heavily commercially fished regions (Adelaide River, Roper River Blue Mud Bay and McArthur River). Based on this limited data, there does not appear to be any significant trend in the median carapace size of the catch sampled. A follow-up workshop to the one undertaken in 1996 was held in Darwin in August 2000 to review the research directions, update and analyse work that had been undertaken since 1996. Dr Walters was again invited to lead the review. Results of the analyses undertaken indicate that the high catch rates reported over the past four years were not solely caused by increased fishing effort. Dr Walters suggested that such increases were due to consecutive episodes of unusually high recruitment caused by favourable environmental conditions. He also stated that it is unlikely that such high catch rates would be maintained and catches may well return to previous levels in the future. For this reason it was strongly recommended that fishing effort should not be permitted to increase, as this may result in overfishing. A Fishery Assessment Report outlining research in more detail has been completed in 2000 and is available from DPIF publications.