Basin-Scale Connectivity of Blue Marlin in the Western Atlantic

Several complementary approaches were used to examine Gulf of Mexico-Caribbean connectivity of early life and adult stages of Atlantic blue marlin.  Collections of larvae and bio-physical transport models were used to retrospectively determine the spawning locations of blue marlin collected in the northern Gulf of Mexico (NGoM).  Predictions from backtracking models indicated that the majority of blue marlin larvae originated from spawning events in the NGoM; however, spawning activity in the southern waters near the Yucatan Channel also contributed larval recruits to the NGoM.  Electronic tagging of adults showed that that the majority of blue marlin remained in the NGoM throughout the spawning season, with longer tracks (6-12 months) indicating that the southern GoM (Bay of Campeche) served as an important overwintering habitat. Although movement into the Straits of Florida and Yucatan Channel were observed, dispersive behaviors were more restricted than previously recognized and support the premise that the GoM is suitable, year-round habitat of blue marlin.  Regional differences in whole otolith chemistry (lifetime signature) were also detected for adult blue marlin collected in the GoM and Caribbean.  These data are in accord with tagging results and suggest that mixing of GoM and Caribbean contingents may be limited.