What are the effects of climate on the offshore and onshore movements of adult grooved tiger prawns Penaeus semisulcatus in tropical northern Australia?

Abstract

AbstractHistorical catch per unit effort (CPUE) from the period in the development of commercial fisheries prior to the implementation of any temporal or spatial closures can provide insight into how environmental factors affect life history events. These insights can then inform contemporary fishery management practices to improve sustainability. We examined the timing of the offshore dispersal and onshore movement to aggregate on the spawning grounds of the grooved tiger prawn Penaeus semisulcatus in the north‐west Gulf of Carpentaria using all available historical CPUE data between 1970 and 1987. The impact of climate conditions on the timing of the winter minimum CPUE (dispersal) was quantified by fitting univariate relationships with non‐parametric weighted local regression (Loess). The timing of the winter minimum CPUE was delayed by 5 weeks in years with at least 1 week of rainfall > 250 mm, and was delayed by 5 weeks in years when the wet season continued through April, rather than ending in March. Under current climate predictions, rainfall is projected to increase in variability in this region. Our results indicate that the sustainability of the prawn trawl fishery may be enhanced if seasonal fishing effort restrictions and closure dates are not fixed, but are managed to reflect variation in the timing of the end of the previous wet season.