Foraging Ecology of Hawksbill Sea Turtles in the Gulf of California, Mexico

 The article Foraging ecology of critically endangered Eastern Pacific hawksbill sea turtles (Eretmochelys imbricata) in the Gulf of California, Mexico published by Elsevier, analyzed various aspects of the hawksbill sea turtle to determine what influenced their site fidelity or how fixed they were in routines.  Specifically, they analyzed feces, behavior, diet, and habitat to determine how these influenced their site fidelity. This was located at Isla San José, an island southwest of the Gulf of California and is a national protected area. Each turtle that was captured was measured by straight carapace length, curved carapace length, straight carapace width, curved carapace width, body depth, plastron length, total tail length, and body weight. They were then tagged and released. The acoustics were monitored with at least one receiver per area and properly spaced to avoid overlapping detections. Forward-facing video camera harnesses were used for less than 24 hours on the sea turtles to record foraging bouts. Feces were analyzed to determine the percent composition of each food group. Benthic surveys were conducted to compare the available food in foraging habitats. From these methods, a variety of results were found. The mean of the curved carapace was found to be 35.1 to 90.3 cm (mean 51.7 cm) and the mass ranged from 5 to 68 kg. The Overall Residency Index ranged from 0.087 to 0.922 and 59% of the turtles were detected on their array at least half the time they were monitored. Their displacement ranged from 0-8.2 km. Habitat Fidelity Indices showed that 39 turtles remained within the habitat they were caught in. Regarding their behavior, they spent significantly more time swimming and resting respectively than feeding. Their main source of food was as follows: 43% algae, 26% sponge, 11% tunicate, and 1% mangrove (19% was unidentifiable). However, in their feces, it was found to be 44.2% sponge, 21.7% colonial tunicates, 15% red mangroves, and 12% green algae. Overall, this study shows how mangrove estuaries are important for sea turtles because they are an important foraging ground for juvenile and some adult hawksbills. They also found a high residency level within the islands foraging ground that reflected other researched areas. Again, sponges and algae were found to be important in the hawksbills’ diet since it made up the majority of their foraging and fecal matter. All of this information is important to consider when attempting to provide more effective conservation and recovery strategies for hawksbill turtles. Mangrove estuaries specifically benefit sea turtles and can provide important foraging habitats for juvenile hawksbills. In conclusion, researching the foraging areas of hawksbill turtles helped determine what type of environment is best suited for supporting them and the areas that should be more conserved to protect their population size.

Article link: https://reader.elsevier.com/reader/sd/pii/S0141113621002889?token=16C48A4891A2E44EE547CF5F0D47529AF9D2B6111E103C1CC59A5AAA2496B11AE285A40D8F2928F56D2A09EE4F544607&originRegion=us-east-1&originCreation=20230502013056