Development of a spatial multi criteria decision analysis system using geo-referenced fishery-dependent data in the Tasmanian abalone fishery

Assessments of abalone fisheries are typically based on large spatial reporting units, with imprecise data (catch, effort, location). Fishery independent data collection to determine stock status is cost prohibitive, and declining in all Australian Abalone fisheries. Capturing the changes in fisher behaviour and fleet dynamic are central to attribution of changes in CPUE signals to stock decline or, changed harvest strategy, or both. An electronic data collection and analysis system has been developed at the University of Tasmania, using GPS and depth/time data loggers to collect high-resolution, high-quality spatial location and effort data from abalone divers. This geo-referenced fishery-dependent data provides a range of quantitative, unbiased spatial performance measures that can be used in an empirical assessment process. Application of spatial Multi Criteria Decision Analysis provides an objective framework for assessing the performance of abalone or any dive-fishery, with the flexibility of operating at any desired spatial scale. Pilot data from the Tasmanian Abalone fishery are presented here to illustrate the potential application of MCDA approaches for fishery assessment.