Abstract

Whale sharks (Rhincodon typus) are typically solitary animals; however, in the northern Gulf of Mexico they form large aggregations at shelf-edge banks during summer. While there is an understanding of their seasonal distribution in the region, knowledge of movements once they leave aggregation sites is limited. Here we report the movements of 44 satellite tagged whale sharks within the Gulf of Mexico from 2008-2014. Most sharks were tagged at an aggregation site off the coast of Louisiana. State-space modeling was applied to movement data to generate most probable tracks and used to analyze seasonal trends in distribution. Sharks ranged from 4.6-12.2 m total length (n = 44; mean 7.9 ± 0.3 m SE) with a male to female ratio of 5:1. Mean number of days-at-liberty was 97 days (± 15 SE) and all but four individuals remained within the Gulf of Mexico. Shark movements occurred throughout Gulf of Mexico with a net southward movement during cooler months. Additionally, several sharks moved into the Caribbean Sea, demonstrating connectivity among documented aggregation sites in the western North Atlantic Ocean. These broad movements necessitate multinational, cooperative efforts to improve management whale sharks in the western North Atlantic Ocean.

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