Independent Estimates of Catch by Private and Public Access Fishers Avoid Between-Group Sources of Error in a Recreational Fishing Survey

Many recreational fishing surveys assume that fishers who use private or public property to gain access to the fishery behave similarly, but divergent behavior may result in bias and excessive error due to between-group variation. In a 2002 survey of the recreational catch of blue crab Callinectes sapidus in Maryland, we interviewed waterfront property households by telephone and sampled public access boat ramps to obtain independent estimates of private and public access catch and effort. Waterfront property households caught more crabs than fishers from public boat ramps but achieved this only by using effort over an order of magnitude larger. They maintained a consistent catch from July to September, whereas catch from public access sites showed a well-defined peak in August. Estimating catch independently for private and public access avoided bias and between-group error generated by such differences. As a result, independent estimation of catch by private and public access users is a useful option for marine recreational surveys, under the conditions of significant and exclusive private access, large public access bias, and low correlation between effort and catch. Received June 27, 2012; accepted November 3, 2012