Linking oceanography and bluefin tuna movements in the Northwest Atlantic

No abstracts are to be cited without prior reference to the author.

For highly mobile predators such as Atlantic bluefin tuna (ABFT), appropriate oceanographic structure and biophysical interactions create dynamic feeding opportunities. The location and persistence of appropriate watermass features along their migration routes should influence ABFT residence times, energy stores, larval and reproductive success, and vulnerability to capture. Bluefin tuna may seek specific physical conditions to aid physiological functions such as thermoregulation and food assimilation. Gutenkunst et al. (2007) previously identified two movement modes, traveling and foraging, on coastal foraging grounds. However, time and spatial scales were limited (e.g., 48 h, 150 km tracks). Recent advances in satellite and electronic tagging technology and light based geolocation have revealed the scope and complexity of ABFT distributions. Using spatial and behavioral results obtained from adult ABFT tagged with popup archival satellite tags for up to one year in the NW Atlantic, we examined the relationship between persistent oceanographic features and behavior type and depth patterns, and interplay of ABFT depth patterns and behavior. By developing a complete picture of habitat utilization of ABFT, we hope to better understand long term shifts in their distribution and abundance, and contribute to population rebuilding efforts through better understanding of their ecosystem. Our approach utilizes a framework useful for combining geolocations with depth data and the physical environment.