Speaker

David Richardson, Ph.D., Research Fisheries Biologist, Oceans and Climate Branch, Northeast Fisheries Science Center, NOAA

Atlantic Bluefin Tuna Spawning in the Western Atlantic Ocean

There is currently a lack of consensus on the spatial, seasonal and decadal-scale persistence in the patterns of Atlantic bluefin tuna (Thunnus thynnus) spawning in the western North Atlantic Ocean. I will be discussing a project that reevaluated larval bluefin tuna samples dating back to the 1970s, reviewed reproductive studies dating back to the 1950s, and evaluated electronic tag and sea surface temperature data. Our analysis is consistent with bluefin tuna having a near continuous spawning distribution that starts in April in the southern Gulf of Mexico and northwest Caribbean, progresses through the western Sargasso Sea in June and finishes in early-August in the Slope Sea, with the northern Gulf of Mexico and western Slope Sea the two most prominent spawning locations within this broader area. This spawning distribution stands in sharp contrast to the predominant view less than a decade ago that the Gulf of Mexico is the near exclusive western Atlantic spawning ground of bluefin tuna. In this talk I will also discuss research planned for 2025 including: 1) a dedicated cruise on a commercial pelagic longline vessel, 2) an ichthyoplankton sampling cruise to the Slope Sea and 3) the use of bluefin tuna larvae collected in the Slope Sea for an ongoing genetics-based Close Kin Mark Recapture study.