Marine recreational fishery surveys that estimate catch rate by sampling fishers who use public access often assume that fishers using private access and public access catch the same amount per trip taken. Despite the risk of bias, this assumption has not been tested by comparing private-access users to the general population of fishers. During a survey of the recreational fishery for blue crabs Callinectes sapidus in Maryland, households from a list of waterfront properties were sampled by telephone at the same time as sampling of households from all coastal counties. Fishers from waterfront households overwhelmingly used private access. Waterfront households often caught a similar amount per month as coastal county households did, but catches for waterfront households were taken during more trips, resulting in catch rates that were 74% lower. Consequently, estimating catch rate by sampling only public-access users results in a bias towards overestimation of the recreational catch. We strongly recommend that marine recreational surveys test this assumption for frames that only cover public-access users, especially in regions with substantial private access.
