Dolphins were accidentally caught in a Western Australian trawl fishery from 2003 to 2009. Data showed dolphins were caught in all areas, depths, and times of the year. Independent observers' records were better at predicting dolphin catches than skipper logbooks. Factors affecting dolphin bycatch included the fishing vessel, time of day, and the use of bycatch reduction devices (BRDs). BRDs reduced dolphin bycatch by 50%, but some dead dolphins were not recorded because they fell out of nets with bottom-opening escape hatches. Adjusting fishing efforts spatially or seasonally may not reduce dolphin bycatch rates. Trials of BRDs with top-opening escape hatches are recommended to help dolphins escape. The impact of trawling on this dolphin population is unknown without more information on dolphin numbers and genetic connections with other dolphin groups.