Some great hammerhead sharks in the Bahamas have been found to spend all year in their protected home waters, skipping the typical 3,000-kilometer migrations that others make between Bimini and offshore Virginia. The reason behind this behavior may be linked to their preferred foods. Scientists have discovered that their favorite foods could influence whether they choose to stay or go, similar to how humans choose to travel for specific food cravings. Research conducted in Andros, Bahamas, where a shark sanctuary was designated in 2011, has provided insights into the hammerhead sharks’ travel habits.
Tracking tags and tissue samples were taken from hammerheads in the Bahamas over a period of six years. Out of 78 observed or captured sharks, tissue samples were taken from 22 and satellite tags were placed on seven. While some sharks exhibited the typical long-distance migrations away from the Bahamas, others stayed put in Andros throughout the year. By analyzing the isotopes in the sharks’ tissues, researchers found evidence of individual variations in their diets. Different sharks showed preferences for prey such as silky sharks, barracuda, and stingrays, indicating potential feeding habitats based on the types of fish they consume.
The diverse diet preferences of the great hammerhead sharks suggest that their decision to stay or move may be influenced by their food sources. Some sharks predominantly fed on silky sharks, which are found in the open ocean, while others favored barracuda and stingrays, which live in different habitats. Understanding the dietary habits of these endangered animals can help in conservation efforts, particularly for those that travel long distances and risk encountering industrial fisheries. The global population of great hammerheads has decreased by more than 80% over the last three generations, highlighting the importance of protecting these mobile species.
The findings of the research suggest that international collaboration is essential for conservation efforts aimed at protecting great hammerhead sharks. By identifying the food preferences of these sharks and understanding their behavior, researchers and conservationists can develop strategies to safeguard both resident and migrating individuals. The presence of protected waters where some sharks choose to stay year-round underscores the significance of creating marine sanctuaries and implementing conservation measures to ensure the survival of these majestic creatures. Through continued research and monitoring, scientists hope to gain further insights into the factors influencing the behavior and movements of great hammerhead sharks in the Bahamas and beyond.
