Elements of the Ecology and Movement Patterns of Highly Migratory Fish Species of Interest to ICCAT in the Sargasso Sea

This paper provides information on the ecology and movement patterns of a total of 16 different fish species whose distributions include the Sargasso Sea. These species are divided into four groups that broadly correspond with ICCAT species groupings: Group 1 – Principal tuna species including yellowfin tuna, albacore tuna, bigeye tuna, bluefin tuna and skipjack tuna, Group 2 – Swordfish and billfishes including blue marlin, white marlin and sailfish, Group 3 – Small tunas including wahoo, blackfin tuna, Little Tunny (Atlantic black skipjack tuna) and dolphinfish, and Group 4 – Pelagic sharks including shortfin mako, blue and porbeagle. For each species, information is provided on ecology and habitat use in relation to oceanographic parameters such as water temperature, depth preference and dissolved oxygen. In addition, movement and migration patterns are discussed in relation to conventional tag-recapture results and more recent PSAT (Pop-up Satellite Archival Tag) tagging. The importance of Sargassum as essential fish habitat is discussed and is linked to the feeding habits of tunas and other pelagic predators. Flyingfishes are an important prey species in the diet of tunas and billfishes and, as they are largely dependent on Sargassum mats as spawning habitat, the Sargasso Sea plays a fundamental role in the trophic web of these highly migratory, pelagic species. Recent findings from PSAT tagging of several pelagic shark species has revealed the importance of the Sargasso Sea in their life cycles.