Abstract

Ichthyoplankton surveys were conducted in the summers of 2005 and 2006 to identify areas in the northern Gulf of Mexico with high larval billfish densities. Neuston net tows were conducted at 60 - 62 different sample sites along two transects at 27 and 28 degrees North latitude between 90 and 94 degrees West longitude. In 2006, our sampling efforts were concentrated around areas with similar conditions to areas where large numbers of larval billfish were caught the previous year. A total of 2,589 billfish larvae were collected from five cruises. The mean density of larvae per sample ranged from 0 – 53.82 larvae per 1,000 m2. The size range of the larvae collected was 2.2 – 31.0 mm. The highest densities of billfish larvae were located at the fronts of anti-cyclonic eddies. An examination of the gut contents revealed that the diet of larval billfish mainly consists of cyclopoid copepods and ichthyoplankton. Our results provide confirmation that the Gulf of Mexico provides important nursery habitat for billfish larvae.

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