Cetacean and sea turtle visual observations using line-transect survey methods aboard a NOAA DeHavilland DHC-6 Twin Otter (TO) aircraft in the Gulf of Mexico, during the Gulf of Mexico Marine Assessment Program for Protected Species (GoMMAPPS survey TO18Fa) from 10/12/2018 to 11/28/2018 (NCEI Accession 0243468)

As part of the Gulf of Mexico Marine Assessment Program for Protected Species (GoMMAPPS), the Southeast Fisheries Science Center (SEFSC) conducted aerial surveys of the U.S. continental shelf waters (up to the 200-m isobath) in the Gulf of Mexico from 10/12/2018 to 11/28/2018. The survey was designed for a two-team independent visual observer approach with distance sampling to estimate abundance and characterize spatial distribution of marine mammals and sea turtles. This dataset includes marine mammal and sea turtle visual observation data and effort points with surveying conditions that can be used in abundance and density modeling per visual line-transect survey protocols. This dataset also includes marine mammal photographs used to aid in species identification, as well as photographs and coordinates of algal blooms.