Feeding ecology of larval Atlantic bluefin tuna, Thunnus thynnus, from the central Gulf of Mexico

Inter-annual and ontogenetic differences in diet and feeding intensity were examined for larval Atlantic bluefin tuna, Thunnus thynnus (Linnaeus, 1758), collected from the central Gulf of Mexico (GOM) during May 2008, 2009, and 2010 [n = 100; 3.0-6.7 mm body length (BL)]. Predominant prey groups were copepods, cirripeds, and cladocerans. Inter-annual differences in diet resulted from changes in the consumption of copepods and unique prey groups (e.g., cladocerans). Body length had an effect on T. thynnus diet, and a relative increase in copepod consumption occurred beyond 5 mm. Feeding intensity (i.e., the number of prey per digestive tract) was higher during 2010 than 2008 and 2009 and positively correlated with increasing T. thynnus BL. No fish prey were observed, which suggests piscivory in GOM T. thynnus does not occur at sizes < 6 mm. Patterns in feeding incidence (i.e., total number of digestive tracts with prey divided by the total number of digestive tracts) contrasted with reports from the Mediterranean Sea, suggesting T. thynnus may have distinct early life history strategies between the two regions.