The initial conditions and carrying capacity estimates for the prawn stocks in NWS InVitro were calculated using catch data and biological information taken from the WA Department of Fisheries (2002) submission to Environment Australia regarding the Exmouth Gulf Prawn Fishery. This information was converted to total stock sizes using the assessment rule of thumb that catch at Maximum Sustainable Yield equals 12% of virgin biomass and cross checked using the methods outlined in Taylor and Dichmont (2001). This resulted in an upper bound on the estimate of maximum total biomass of 15000t for western king prawns, with a lower bound of 8000t and a median of 12000t. For the banana prawns the upper bound on biomass was again 15000t, but the lower bound was 4000t and the median was 8000t. All other prawn biological parameters were based on Kailola et al. (1993) and Taylor and Dichmont (2001).