At-sea factors that affect yellowfin tuna grade in the Gulf of Mexico pelagic longline tuna fishery

Abstract Burnt tuna syndrome (BTS) is a term used to describe changes in raw tuna (sashimi) that is characterized by pale color, poor texture, and an “off” flavor. This reduction in tuna quality results in a much lower price for the fisher and significantly affects the profitability of tuna fisheries. In this study, we examine how at-sea factors, including the capture process, affect the quality of yellowfin tuna, Thunnus albacares caught in the northern Gulf of Mexico pelagic longline fishery. Hook timers were used to record the elapsed time between a tuna taking the hook and its eventual landing. The elapsed time on the hook, tuna length, and fish boarded alive were found to be positively correlated with the proportion of tuna grading #1, while fish boarded dead and days on ice were found to be negatively correlated.