Grant: 20-007R
Project Title: Population structure and foraging ecology of loggerhead turtles in Crystal River
Project Manager: Dr. Mariana Fuentes
Organization: Florida State University (Research and Educational Institute)
Grant Amount: $23,281.86
Completion Date: 2022-09-07
Summary: Extended efforts have been undertaken in Florida to generate and compile biological and ecological information of sea turtles in foraging habitats. The neritic habitats along the coast of Florida are crucial for the development and persistence of both immature and adult turtles of the Northwest Atlantic Ocean loggerhead Sea Turtle Distinct Population Segment. However, an important geographic gap in in-water research remains in the southern Big Bend region in northwest Florida. While more is known about the distribution, movement and habitat use of juvenile Kemp’s and green turtles in this region, there are still important information gaps on the foraging ecology of the less abundant loggerhead turtles in the region. During the last two years we have captured 61 loggerhead turtles across 30 sampling days (CPUE of 2 turtles/day). This indicates that there is a larger aggregation of loggerhead turtles in the area than previously thought. However, there is a need to better understand the population structure and dynamics as well as the extent to which the habitats in this region contribute as developmental and foraging habitat for the Northwest Atlantic Loggerhead DPS. 
Results: As of the 12 April 2022, we have completed 8 field trips totaling 22 sampling days (2021: 23-26 April, 3-7 June, 16-19 July, 12-16 August, and 30 October – 3 November, 9-12 December; 2022: 25 February – 1 March, 8-12 April). Six days were lost due to bad weather. During these trips, a total of 80 loggerheads were sighted and 35 captured with SCLs ranging from 49.8 cm to 95 cm (mean ± SD: 70.4 cm ± 11.1 cm). One turtle in April 2021 was a recapture from a previous tagging effort by another organization. Survey effort was concentrated off the St. Martin Keys and Mangrove Point based on the capture success of previous trips in the area. Given this survey distribution, the various life stages did not appear to segregate habitat use as each life stage was commonly sighted in the vicinity of the other stages. Loggerhead turtles were sighted at different frequencies by survey month (p < 0.001) and life stage (p = 0.0145), though no interaction between month and life stage were observed (p = 0.8969, Figure 2). Loggerheads were most frequently sighted in April 2022, followed by April 2021, June 2021, and October 2021. December 2021 saw the fewest turtles, followed by February 2022, August 2021, and July 2021. Regardless of month, subadult loggerhead turtles were the most frequently sighted, followed by adults, then juveniles. In total, 34 adult (including 2 male and 2 of unknown sex), 42 subadult, and 4 juvenile turtles were sighted.