Estimation of recreational bag limit noncompliance using contact creel survey data

Bag limits are commonly used to manage recreational fisheries, but the effect of noncompliance with these regulations is rarely evaluated. I developed a method to estimate noncompliance with recreational bag limits using creel survey data. This approach allowed for two populations of angler trips, compliant and potentially noncompliant, and estimated the proportion of potentially noncompliant trips. The model included a mixture of a negative binomial distribution for potentially noncompliant trips and a truncated negative binomial distribution for compliant trips. The method was applied using four separate models with different assumptions about noncompliance to harvest angler−1 trip−1 data from the recreational king mackerel (Scomberomorus cavalla) fishery in North Carolina, U.S. The model that estimated a single potential noncompliance parameter had the lowest (best) Akaike's Information Criterion value, and the estimated proportion of potentially noncompliant trips was about 36%. However, only about 1% of trips exceeded the bag limit because few trips reached the bag limit, which resulted in about 7% of harvest due to noncompliance. Studies that evaluate the likely consequences of bag limits on harvest and fishing mortality should include effects of noncompliance.