Abstract

Stomach contents analysis was used to quantitatively describe the diet of wahoo, Acanthocybium solandri, from the northcentral Gulf of Mexico. Stomachs were collected opportunistically from wahoo (n = 321) that were weighed (TW, kg) and measured (FL, mm) at fishing tournaments during 1997 - 2007. Stomachs were frozen and later thawed for removal and preservation (95% ethanol) of contents to facilitate their examination and identification. Empty stomachs (n = 71) comprised 22% of the total collection. Unfortunately, the preserved, un-examined contents from 123 stomachs collected prior to Hurricane Katrina (August 2005) were destroyed during the hurricane. Consequently, assessments of wahoo stomach contents reported here were based on the contents of the 65 ‘pre-Katrina’ stomachs, in addition to the contents of 62 stomachs collected ‘post-Katrina’ during 2006 and 2007, for a total of 127 stomachs. Wahoo with prey in their stomachs ranged 859 - 1,773 mm FL and 4.4 - 50.4 kg TW and were sexed as: 31 males, 91 females and 5 sex unknown. Stomach contents reported in this study were identified to the lowest taxon possible (depending on the stage of digestion) and analyzed for %N, %W, %F, IRI y %IRI. Stomachs contained pelagic/epipelagic fishes and squid, including evidence of species associated with pelagic Sargassum. Prey (309 identified items) belonged to 27 taxa and ranged in stomachs from only one prey in 74 stomachs (58% of total stomachs) to 9 prey in a single stomach. Dominant fish families in the diet were Carangidae, Coryphaenidae, Scombridae and Exocoetidae. A moderate ontogenetic shift in the diet was observed among three size classes of wahoo. The diversity of fishes in the diet suggests that wahoo is an opportunistic predator that feeds on a variety of regionally abundant prey

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