Research Document - 2011/120
Stock Assessment Framework for the British Columbia Geoduck Fishery, 2002
By C.M. Hand and D. Bureau
A stock assessment framework for the provision of biomass estimates in a quota-managed geoduck fishery is presented. Presentation of this framework was driven by the need to examine the sources of uncertainty and error in the parameter estimates necessary for biomass calculation, and to prioritize data analysis and future data collection for more effective stock assessment.
Through collaboration with resource stakeholders, a large amount of fishery-dependent and fishery-independent data have accumulated, particularly in the last decade. The methods used to collect and analyze data on geoduck density, mean weight and geoduck bed area are described, and the errors, biases and assumptions discussed. Geoduck bed area is identified as the parameter that is measured with the least accuracy and is recommended as the highest priority to resolve. The current methods of extrapolating estimates of density to unsurveyed geoduck beds assume that populations that are closer together are more similar than those more distant. It is recommended that more spatially-explicit approaches be used for extrapolation which utilizes all of the available information on geo-physical properties of the geoduck bed and the associated characteristics of the populations within them.
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