Supplemented access point sampling designs: A cost-effective way of improving the accuracy and precision of fishing effort and harvest estimates derived from recreational fishing surveys

We describe a cost-effective method for improving the accuracy and precision of fishing effort and harvest estimates derived from recreational fishing surveys that include an access point method for effort estimation (e.g., traditional access point surveys and bus route designs). Validated auxiliary data that quantity recreational fishing effort at access points within the fishery are used to supplement an existing access point design. This supplemented access point survey (SAPS) method is a form of double sampling and should be viewed as an extension of an access point design. Case study data from a boat-based estuarine fishery in Australia have been used to demonstrate changes in the relative accuracy and precision between a traditional access point design and the supplemented design. We found that the traditional design provided annual effort and harvest estimates for dusky flathead Platycephalus fascus that were about 7% and 5% lower, respectively, than those obtained with the supplemented design. Importantly, the SAPS method provided improvements in relative precision for annual estimates of effort and harvest of about 76% and 37%, respectively. The SAPS design outperforms other access point designs in terms of relative accuracy and precision because the auxiliary data provide better coverage of the temporal sampling frame for fishing effort. Improvements in relative accuracy and precision are also reflected in harvest estimates because the SAPS design calculates harvest as the product of effort and a harvest rate. The SAPS method can easily be extended to cover multiple sites and offers a cost-effective way to improve estimation procedures for any recreational fishing survey that uses an access point method for effort estimation.