Scoping the knowledge requirements for Murray crayfish (Ueastacus armatus)

The Murray crayfish (Euastacus armatus) is a large freshwater species that is the basis of a popular recreational fishery in many areas the southern Murray-Darling Basin and is considered an iconic freshwater species (Sanger and King 2002). Despite the social importance of Murray crayfish, little information has been formally published. The majority of data are only available as unpublished departmental manuscripts, theses, secondary references to unpublished data, or in items published outside of peer-reviewed scientific journals. Consequently, the information that is available about Murray crayfish is difficult to access. The perception of rural communities and recreational fishers is that Murray crayfish populations have declined in distribution and abundance over the last 50 – 60 years (Pollard et al. 1980; Walker 1982; Barker 1990; Geddes 1990; Horwitz 1990a; Geddes et al. 1993; Horwitz 1995). However, the lack of scientific data regarding its status, biology and the impacts of potential threatening processes, limits the ability to validate the reported declines and develop successful management strategies. This report will review and assimilate all available information on Murray crayfish (both published and accessible unpublished material), and identify key knowledge gaps relevant to sustainable management of the species. Many of the often quoted statements regarding Murray crayfish are second or third hand accounts of unpublished data-sets. In this review, we have tried to use the primary source of the data whenever possible.