Estimating effort from instantaneous counts : a comparison of analysis approaches using 2010 Victoria area recreational survey data / by B.O. Ma, D.C. Pickard, and D.S. O'Brien.: Fs97-4/3005E-PDF

"We performed a preliminary examination, using the 2010 Victoria area recreational creel survey data, to determine if more precise estimates of catch, CPE, and effort could be obtained by stratifying the data beyond the methods currently used. We focused our analysis on calculating activity profiles, which are then used to estimate daily effort from effort counts obtained from aerial surveys. Current methods generate activity profiles that are based on relatively coarse-scale geographical gradients. In the Victoria area this means using interview data across all surveyed access sites to develop activity profiles. We explored the possibility of stratifying the current interview data to generate more sub-area specific activity profiles in three ways. First, we generated activity profiles based on interview data from only landing sites specific to the subarea of interest. Second, we generated activity profiles based on interview data information based on targeted subarea fished. Third, we generated activity profiles based on species targeted by a particular fishing party. We evaluate approaches using effort and the catch of the most desired species in the area – chinook salmon (Onchorhynchus tshawytscha) and halibut (Hippoglossus stenolepsis). The results indicate that utilizing any of the three methods proposed in this study generally do not improve the precision of the catch and effort estimates relative to the current method. This is despite the relatively large interview sample sizes associated with this area. This study suggests that despite the coarse-scale geographical range over which activity profiles are generated, there is no consistent increase in precision by stratifying the data according to landing sites specific to subareas. Furthermore, incorporating information from fishing party interviews such as the targeted subarea and targeted species did not improve precision of catch or effort estimates. Thus, our results suggest that incorporating this information into current analysis methods will not lead to better estimates of catch and effort. However, we highlight additional areas where analysis methodology should be further reviewed"--Abstract, page vi.

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