IMIS - Marine Onderzoeksgroepen

During the months of January and February 2010, 30 daily marine fauna sighting surveys were systematically conducted across the waters of Golfo Dulce, a tropical fiord-like embayment in the South Pacific region of Costa Rica. Special focus was placed on cetaceans, chelonids, whale sharks and pelagic sea snakes. Within the 233 logged observation hours, 234 first-hand sightings were recorded from a small panga; photo-identification was collected for 76% of those sightings. Dozens of marine species were documented during the survey period, but those that played most prominently in the survey were Humpback whales (Megaptera novaengiae), bottlenose dolphins (Turciops truncatus), pantropical spotted dolphins (Stenella attenuata), green/black sea turtles (Chelonia mydas agassizii), olive ridley sea turtles (Lepidochelys olivacea), hawksbill sea turtles (Eretmochelys imbricata), and pelagic sea snakes (Pelamis platurus). The study was marked by a lack of sightings for whale sharks (Rhinocodon typus), a species expected inside Golfo Dulce at the time of study. Sighting coordinates are based on the display of a handheld Garmin handheld GPS III. Measure accuracy is untested. Several other data attributes were also collected during our survey, including: Geographical area, distinctive markings, initial distance from boat, closest approach distance, swim direction, behavior, associated fauna, and environmental conditions (bi-daily). The best estimate recorded was used as the obs_count; when it was blank, the minimum estimated number of animals was used; when it was blank, too, the sum of the number of adults and young was used.