Survey summary report : Line-transect aerial survey, October–November 2025: Southeast Fisheries Science Center

The Southeast Fisheries Science Center conducted an aerial survey over the U.S. continental shelf waters of the Gulf of America (formerly the Gulf of Mexico; hereafter, the Gulf). The survey was conducted between October 6 and November 26, 2025, aboard a NOAA Twin Otter aircraft at an altitude of 600 feet and a speed of 100 knots over ground. Survey tracklines were oriented perpendicular to the shoreline and latitudinally spaced 20 km apart. The primary goal of this survey was to characterize the distribution and abundance of marine mammals and sea turtles in the Gulf and update the species distribution models. The survey was designed using distance sampling methods with an independent two-team approach to correct for perception bias in the resulting estimates. A total of 8,890.7 km of tracklines were surveyed on-effort and included 238 marine mammal sightings of four identified species. Eighty-six percent of all cetacean sightings were of common bottlenose dolphins. There were 131 sea turtle sightings, with loggerhead and Kemp’s Ridley totaling 31% and 21% of all identified sightings, respectively.