Dinâmica espaço-temporal de diferentes fases do ciclo de vida da albacora laje (Thunnus albacares) explorada comercialmente no atlântico

Abstract

In last decade, the yellowfin tuna (Thunnus albacares) was the second most important tuna production of the world, with approximately 1.25 million tons per year. The three major fishing gears involved at yellowfin catches in the Atlantic are: purse seine (66.46 %), longline (18.67 %) and pole and line (9. 05 %). This study used the generalized linear models for investigate the spatial and temporal distribution of three stages yellowfin tuna life cycle (juvenile - ≤ 50 cm, sub-adult – < 50 cm e ≥ 100 cm and adult - > 100 cm). We used the catch rates of the three main yellowfin tuna commercial fisheries. In addition, it was analyzed the sea surface temperature (SST) like prospective index of important environmental variables related to yellowfin distribution. In the models fitted to purse seine, longline and pole and line fisheries data, the life stage factor was important to explain the catch rates variation. The predicted catch rates by longline model were higher in Atlantic west when compared with the east side. In opposition, the estimates of purse seine and pole and line models were higher in east than west. The phenomenon is probably associated to three elements: a) thermocline depth, b) fishing gear depth and c) vertical distribution of life stages. The life stages spatial and seasonal patterns were divergent. Overall, periods of higher estimates of catch rate are associated with reproductive and trophic activity. The exception were the juveniles. For this life stage, the results suggest that the horizontal distribution is associated with distinct phenomenon for each Atlantic region: a) thermocline depth for western and b) period of fishing recruitment for eastern.