Volume 72

Diet observations from tournament landed Swordfish, Xiphias gladius, in the north central Gulf of Mexico

Higgs, J; M. Andres; K. Price; A. Millender; N. Brown-Peterson; J. Franks
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Date: November, 2019

Pages: 354

Event: Proceedings of the Seventy-Two Annual Gulf and Caribbean Fisheries Institute

City: Punta Cana

Country: Dominican Republic


Targeting Swordfish, Xiphias gladius, as a sportfish in the north central Gulf of Mexico (ncGOM) is drastically increasing in popularity providing a unique opportunity to investigate their life history and diet. We opportunistically collected 27 female and 6 male Swordfish, ranging in age from 3-11 years old, during the 2017 and 2018 Mississippi Gulf Coast Billfish Classic. Stomach contents were found in 87% of Swordfish (n = 29; 25 female, 4 male). Prey item identification was difficult due to highly degraded tissue but resulted in broad taxonomic identification with teleosts comprising (63%) of overall diet; followed by cephalopods (20%), vegetative matter (3%), crustaceans (2%), and unknown remains (12%). Further prey identification was conducted though DNA barcoding of unidentified teleosts and cephalopods (COI; n = 139, and 28, respectively). Molecular identifications were paired with associated hard structures (i.e., otoliths and squid beaks) to further resolve prey item identifications. This indicated Luminous Hake (45%O), Steindachneria argentea, and Blue Runner (45%O), Caranx crysos, as the most abundant identifiable prey. Ongoing molecular identification and subsequent hard structure comparison will better define ingested prey. Our results suggest that Swordfish in the ncGOM primarily feed on teleosts rather than squid, which is contrary to what has been reported for other Atlantic Ocean Swordfish populations.

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