Historical changes in fishing efficiency in the west coast demersal scalefish fishery, Western Australia: implications for assessment and management

Marriott, R. J., Wise, B., and St John, J. 2011. Historical changes in fishing efficiency in the west coast demersal scalefish fishery, Western Australia: implications for assessment and management. – ICES Journal of Marine Science, 68: 76–86. The west coast demersal scalefish fishery off the southern part of Western Australia has experienced technological creep over the past 20 years, resulting in improved fishing efficiency. The aim of this study was to obtain quantitative measures of efficiency improvements arising from the historical adoption of several important technologies from the surveys of experienced skippers. Survey results suggest that the relatively rapid adoption of Global Positioning Systems from 1989 to 1991 had a large and overriding effect on fleet-wide fishing efficiency. Additive effects from the fleet-wide adoption of colour sounders and hydraulic reels on effective fishing effort and the catch rates of West Australian dhufish (Glaucosoma hebraicum) and pink snapper (Pagrus auratus) were also demonstrated. Historical logbook data were independently analysed as a secondary check of these findings for three of the surveyed skippers, which identified that GPS adoption had a significant, positive influence on the catch rate for two vessels, but not for the third, highlighting potential variation in this response among skippers. The results have contributed towards improved understanding of the historical dynamics of the fishery and of the factors that have affected, at least in part, historical changes or, in some instances, a lack of change in observed effort and catch rates.