An analysis of Pacific striped marlin (Tetrapturus audax) horizontal movement patterns using pop-up satellite archival tags

Previous studies reached inconsistent conclusions when using morphometrics, molecular markers, conventional tags, or spatial analyses of catch per unit effort rates in attempts to characterize movement patterns and stock structure of Pacific striped marlin (Tetrapturus audax Philippi, 1887). A better understanding of the movement patterns of this species is important, since striped marlin are the only istiophorid for which there are targeted commercial fisheries. To this end, 248 pop-up satellite tags were placed on striped marlin at regions of high seasonal abundance in the Pacific Ocean. Fish were caught on rod-and-reel, tagged, and released off Mexico (Baja California), Ecuador (Galápagos Islands and Salinas), New Zealand, and eastern Australia. Small numbers of striped marlin were also opportunistically tagged in other regions of the Pacific. The longest days-at-liberty for fish tagged at each region ranged between 4 and 9 mo, with the mean days-at-liberty ranging from 2 to 3 mo. Within the time frame of this study, striped marlin exhibited a degree of regional site fidelity with little to no mixing between fish tagged at different regions. One notable track extended over 2000 km away from New Zealand before circling around New Caledonia and returning to within 400 km of the origin 8 mo later. It is likely that marlin stocks can be managed and assessed on a region by region basis and continued tagging and genetic studies will allow these regions to be better defined.