The Texas Parks and Wildlife Department (TPWD) conducted surveys to determine the accuracy of trip durations reported by marine sport-boat fishermen. The surveys were conducted at boat ramps on 21 d during May-August 1982. The fishermen's reported trip duration (nearest 0.5 h) was compared to TPWD's observed trip duration (nearest 0.1h). No significant differences were found between the reported and observed trip durations by sport-boat fishermen. Eighty-six percent of all differences between reported and observed trip durations were within +/- 1.0 h of zero, and 68% of those differences were within the precision desired (nearest 0.5 h). Therefore, the mean trip duration reported by sport-boat fishermen during 1-d fishing trips is an empirically unbiased estimate of actual mean trip duration. The accuracy of trip duration reported by sport boaters was not influenced by the actual trip length.