Feeding ecology of the sailfish Istiophorus platypterus Shaw, 1792 from the coastal waters off Côte d’Ivoire, West Africa

Abstract

The feeding habits of Istiophorus platypterus from the coastal waters off Côte d'Ivoire were examined, based on captures made from January 2018 to December 2019 by artisanal fishers of Côte d'Ivoire. Diet was described using the Index of Relative Importance (%IRI) according sexes, size groups and marine seasons. The food overlap was analysed using the Morisita index. A total of 279 specimens ranging in size from 106 to 239 cm lower jaw fork length (LJFL) were used. Of the stomachs examined, 198 (70.96%) contained food and 81 (29.03%) were empty. The results indicated that sailfish has epipelagic and meso-bathypelagic feeding habits, preying upon a wide number of prey taxa (22 species) but with a diet dominated by teleost fishes, especially Auxis thazard (52.76 %IRI). The Morisita index and the Spearman rank correlation coefficient showed similarity of the diet between sexes (Cλ > 0.60; Rs = 0.675 and p = 0.0004, marine seasons (Cλ > 0.60; Rs = 0.538 and p = 0.008) and size (Cλ < 0.60; Rs = 0.58 and p = 0.003). The Amundsen Feeding ecology… Marius Trésor DANHI et al.