A series of analyses of catch-effort data from compulsory commercial logbooks and from the Department’s Long-Term Monitoring Programme (LTMP) were conducted after the Workshop. Although not part of the Project plan, these were initiated as a result of questions arising from the Workshop participants about the reliability of the data used in the simulation modelling. Exploration of the logbook data and results of the analyses suggest that biases in the data (from a variety of sources, but principally the widespread use of more than the permitted number of pots) may be giving an over-optimistic view of the status of the East Coast mud crab resource. In particular, if a significant proportion fishers are reporting that catches are greater than they actually are, this will result in an overestimate of the productivity of the stock, and an underestimate of the impact of removing the SSHB. Declining stock density trends in the fishery-independent LTMP data series over the past decade are consistent with the commercial data trends, although the time series is too short to rule out the possibility that this could be part of a decadal-scale environmental cycle. Reliable commercial and recreational crab fishers also report that legal-sized mud crabs are becoming more and more difficult to catch.
Available at: http://works.bepress.com/tor_hundloe/17/