Overview

The tiger shark is a large, circumglobally distributed species found in warm temperate and tropical oceans. The species is best known for its distinctive color pattern and generalist dietary behavior, consuming a wide range of prey spanning multiple taxonomic groups (i.e. birds, fishes, reptiles, etc.). Tiger sharks are highly mobile and use a variety of habitats, including shallow flats with seagrass and mangroves, to coral reefs, and pelagic zones, as well as the deep-sea, where individuals have been observed diving to depths of over 1000 meters. As upper-trophic level predators, tiger sharks play an important role in structuring marine ecosystems through their influence on prey populations. In the waters of Andros Island, with its productive and diverse habitats these sharks may exhibit year-round residency which may emphasize their importance in linking energy pathways and regulating prey communities across habitats. However, the extent to which tiger sharks move among habitats and how these movements influence trophic dynamics of the broader ecosystem remains unclear. This research will use a combination of animal tracking, prey community surveys, and biochemical tracers to gain a deeper understanding of movement patterns, resource use, and predator-prey interactions of this species. The results from this research will provide valuable insight into tiger shark ecology and behavior, to elucidate their role in a multi-habitat system which can be used to advance behavioral theory and to better inform conservation and management decisions.

Conservation Concern

Tiger sharks are caught by commercial, recreational, and artisanal fisheries as both target and bycatch species. In some parts of the world, they are also a major component of shark control programs, which intentionally targets large shark species for culling to reduce perceived risks to human safety. With few available trend data in tiger shark abundance across its geographical range and through history, it is difficult to make informed conservation decisions. However, where long-term catch data is available, differences in population trends by region are evident. In areas off the coast of Australia, catch rates of these sharks have declined largely due to control programs, decreasing to over 60% of historical levels by the early 2000s. In contrast, localized abundances in some parts of The Bahamas have shown a stable pattern, and even a slow increase in the Southeastern United States, suggesting relatively healthier populations in parts of the Northwest Atlantic. Unlike many large, mobile shark species, tiger sharks grow relatively quickly and produce large litters (26-33 pups), though their infrequent reproductive cycle (about once every three years) limits their ability to recover from sustained fishing pressure. Globally, the tiger shark has had an overall population reduction of approximately 30% over the past 70 years and are currently assessed as Near Threatened by the IUCN Redlist (IUCN, 2019), with a decreasing population trend expected into the future. It is critical that we learn more about the ecological role this species plays in ecosystems so that effective conservation and management strategies can be implemented to combat ongoing fishing pressure.