Supplemented roving survey to quantify spatio-temporal recreational fishing effort in an estuarine Ramsar wetland

Abstract

The collection of fine-scale recreational fishing data can assist in assessing the potential impacts on target species and sensitive biota. We employed a thermographic camera, laser rangefinder, compass and custom-designed mobile application to estimate fine-scale recreational fishing effort for blue-swimmer crabs (Portunus armatus) within Peel-Harvey Estuary, a Ramsar-listed wetland. Geo-referenced locations for shore-based recreational fishers were recorded for sixty 18-h fishing days in a 12-month period. Annual fishing effort was estimated to be 100,815 (SE 12,521) fisher hours, 16.3 % greater than estimates that excluded nocturnal fishing from the analysis. Generalized linear models were applied to determine significant factors describing the variability in fishing activity and for planning future cost-effective surveys. The main effects of time of day and wind condition, and the interaction of season with day type and season with region, were significant at the α = 0.05 level. These data suggest that fishers respond to the abundance of legal-sized crabs within the estuary, with peak fishing activity concentrated on discrete areas and times of the year. The methods used in this study can be applied to quantify nocturnal recreational fishing effort, optimize cost-effective recreational fishing surveys, and determine where recreational fishing activity overlaps areas of sensitive biota.