Evaluation of the bus-route creel survey method in a large Australian marine recreational fishery: I. Survey design

Computer simulations were used to test the efficacy of the bus-route method of creel surveys when applied to a large-scale, heterogeneous, Australian marine fishery and to determine an optimal survey design. The simulations were based on real-world data from the South Australian inshore boat fishery and estimates were directly compared with known values of fishing effort. Results indicate that accuracy was not significantly affected by the size of primary or secondary sampling units or by the allocation of waiting times to ramps either equally or proportional to effort. The optimal design proved to be a combination of a smaller PSU with a larger SSU and waiting times allocated equally at all ramps. Using this design, the method yielded estimates of mean daily fishing effort accurate to within 12.6-13.3% of the true value at a sampling frequency of 35% of days with relative precision of 21.8-35.4%. The sampling distribution of the daily estimator was also examined and found to be non-normal. In cases where the distribution of daily fishing effort is highly asymmetrical, the random selection of a SSU can lead to systematic under-or over-estimation of the true value. The contribution of within-day variability to the total variance of the estimator was found to be much smaller than in a previous study and was deemed to be of insignificant magnitude compared with the inherent day-to-day variability in fishing effort caused by factors such as weather and season. (C) 1997 Elsevier Science B.V.