Loggerhead marine turtles (Caretta caretta) nesting at smaller sizes than expected in the Gulf of Mexico: Implications for turtle behavior, population dynamics, and conservation

Abstract

Estimates of parameters that affect population dynamics, including the size at which individuals reproduce, are crucial for efforts aimed at understanding how imperiled species may recover from the numerous threats they face. In this study, we observed loggerhead marine turtles (Caretta caretta) nesting at three sites in the Gulf of Mexico at sizes assumed nonreproductive in this region (≤87 cm curved carapace length‐notch [CCL‐n]). These smaller individuals ranged from 74.0 to 86.9 cm CCL‐n, and the proportion of smaller nesting loggerheads was 0.13 across three study sites: Gulf Shores, AL; Dry Tortugas National Park, Florida (FL); and Everglades National Park (ENP), FL. The greatest proportion of smaller nesters was observed at ENP at 0.24. Tracking data indicated that the smaller nesters migrated shorter distances and swam in shallower waters compared to the larger nesting loggerheads (>87 cm CCL‐n) in our dataset. These results provide valuable information on two of the smallest subpopulations of NW Atlantic loggerheads and understudied ENP turtles. Our results have potential applications in the classification and interpretation of stranding limits and bycatch estimates, population modeling (e.g., stage durations and fecundity), and understanding threats and subpopulation recovery efforts for multiple subpopulations of this imperiled species.

Isotopic niche overlap among foraging marine turtle species in the Gulf of Mexico

“…Body size ranged from 53.6 to 105.8 cm CCL (mean ± SD: 80.0 ± 12.6) for loggerhead turtles, 26.0 to 73.4 cm CCL (mean ± SD: 40.1 ± 7.99) for green turtles, and 26.4 to 61.0 cm CCL (mean ± SD: 46.7 ± 8.36) for Kemp's ridley turtles. Based on these values, the loggerhead turtles were categorized as subadults and adults (Benscoter et al., 2022 ; Bjorndal et al., 2001 ), and the green and Kemp's ridley turtles were categorized as juveniles (Eaton et al., 2008 ).…”

Comparative anatomical study to skeleton for same species of Turtles in Iraq

“…Auther used almost all sea turtles -including marine ones belonging to the family Cheloniidae -to have a shell consisting of a dorsal and ventral shield, and the material that does not consist of it is carnelian brown in color 26 . Like river turtles with different colors, they tend to the dorsal shell to dark brown color in males and females, while the shell The abdomen is dark green.…”

Fine-scale intraspecific niche partitioning in a highly mobile, marine megafauna species: implications for ecology and conservation

“…Turtles sampled in-water are commonly categorized into lifestages (e.g. juvenile, subadult and adult) based on minimum curved carapace length (CCLmin) measurements [ 69 – 71 ]. Nesting females in the Gulf of Mexico are typically 80 cm CCLmin or larger [ 71 ], and so turtles sampled in this study were classified as either subadults (CCLmin < 80 cm) or adults (CCLmin ≥ 80 cm).…”

“…juvenile, subadult and adult) based on minimum curved carapace length (CCLmin) measurements [ 69 – 71 ]. Nesting females in the Gulf of Mexico are typically 80 cm CCLmin or larger [ 71 ], and so turtles sampled in this study were classified as either subadults (CCLmin < 80 cm) or adults (CCLmin ≥ 80 cm). This minimized, but did not eliminate, the chance of incorrectly classifying lifestages in captured turtles without performing invasive procedures such as laparoscopy (see [ 72 ] and references therein).…”