EVALUATION OF THE BUS-ROUTE CREEL SURVEY METHOD IN A LARGE AUSTRALIANMARINE RECREATIONAL FISHERY - I - SURVEY DESIGN

Computer simulations were used to test the efficacy of the bus-route m ethod of creel surveys when applied to a large-scale, heterogeneous, A ustralian marine fishery and to determine an optimal survey design. Th e simulations were based on real-world data from the South Australian inshore boat fishery and estimates were directly compared with known v alues of fishing effort. Results indicate that accuracy was not signif icantly affected by the size of primary or secondary sampling units or by the allocation of waiting times to ramps either equally or proport ional to effort. The optimal design proved to be a combination of a sm aller 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 sa mpling frequency of 35% of days with relative precision of 21.8-35.4%. The sampling distribution of the daily estimator was also examined an d found to be non-normal. In cases where the distribution of daily fis hing effort is highly asymmetrical, the random selection of a SSU can lead to systematic under-or over-estimation of the true value. The con tribution of within-day variability to the total variance of the estim ator was found to be much smaller than in a previous study and was dee med to be of insignificant magnitude compared with the inherent day-to -day variability in fishing effort caused by factors such as weather a nd season. (C) 1997 Elsevier Science B.V.