The Kemp’s ridley (Lepidochelys kempii) is the world’s most endangered sea turtle species. Predominately nesting at only one beach in Mexico, this species declined to an estimated 300 females in the mid‐1980s. Conservation efforts in the United States and Mexico, including a head start programme in southern Texas in which hatchlings were reared in captivity for several months before being released into the wild, resulted in the recovery of this species. Although genetic data have previously been used to assess the success of the head start programme and dispersal of individual adults, data on immature turtles sampled at foraging areas and adult females sampled at the main nesting beach in Mexico are lacking. Genetic characterization of immature individuals is important for understanding recruitment, survival, and population demography, while genetic data on individuals from Mexico are essential for understanding dispersal and overall genetic diversity in this species. To address these gaps, mitochondrial DNA data were collected from 106 immature individuals sampled at four different foraging sites in the northern Gulf of Mexico and from 18 nesting females at the primary nesting beach in Mexico. Two previously unknown mitochondrial DNA haplotypes were discovered among the immature individuals. Except for these two new haplotypes, the genetic diversity of immature individuals in the northern Gulf of Mexico closely corresponds to that of adults sampled in Mexico, which suggests that much of the diversity within the nesting population can be found among immature animals dispersing to foraging grounds, including locations in the northern Gulf of Mexico. Continued monitoring of the genetic variation of different life stages of this species across its distribution range will help assess the success of conservation programmes by ensuring the maintenance of genetic diversity and representation of this diversity across the species’ distribution range.

In the Gulf of Mexico, the bulk of published studies for sea turtles have focused on northern (United States) waters where economic resources are centered, with fewer studies in the southern portion of the basin, resulting in significant knowledge gaps in these underrepresented areas. Similarly, publications on adult sea turtles are dominated by research on females that come ashore to nest and can be readily studied (e.g., through the collection of biological samples and the application of satellite-telemetry devices), whereas information on adult male sea turtles is scarce. The goal of this paper is to begin filling these knowledge gaps by synthesizing available data on adult male sea turtles in the southern Gulf of Mexico. We used satellite-telemetry, boat- and drone-based surveys, and stranding records combined with ocean circulation modeling to better understand the spatial distribution of male loggerhead (Caretta caretta), green (Chelonia mydas), hawksbill (Eretmochelys imbricata), and Kemp’s ridley (Lepidochelys kempii) sea turtles in the southern Gulf of Mexico. These spatially explicit analyses will provide context for opportunistically collected data on male sea turtles and better contribute to the management and restoration of sea turtle populations that use the Gulf of Mexico. Moreover, this synthesis can serve as a launching point for directed studies on male sea turtles in this region.

One hundred new COI sequences of nesting female Kemp’s ridley turtles (Lepidochelys kempii) were obtained in the Rancho Nuevo Sanctuary (RNS). The COI sequences were analyzed and contrasted with others retrieved from BOLD and GenBank with the aim of investigating genetic variability, genetic divergence, and haplotypes of the nesting female population at RNS. Four new COI haplotypes for Kemp’s ridley were described; two are redundant with (LK-RN01) 97 and (LK-COI-01) 17 specimens belonging to the RNS and other localities, respectively. Nucleotide (0.00052) and haplotype (0.303) diversity showed low and conserved COI values The fixation index (FST) between these main redundant haplotypes showed a high degree of differentiation with ~1. Genetic divergence demonstrated clearly two different Kemp’s ridley nesting populations, one from RNS and a second outside Mexico. Phylogenetic COI analysis was useful to differentiate these redundant (LK-COI-01 and RNS LK-RN01) haplotypes and, therefore, these different Kemp’s ridley populations. In addition, phylogenetic COI analysis clearly separates Kemp’s ridley turtles from other sea turtle species, supporting its use as a barcode marker.

From the 7 existing species of sea turtles, two are endemic and one out of them inhabits the Gulf of Mexico and nests mainly in the Rancho Nuevo (RN) Sanctuary, Aldama, Tamaulipas, Mexico. The objective of this work was to determine the DNA barcode by COI gene sequences in Kemp's ridley turtle (Lepidochelys kempii) and to estimate their genetic divergence and diversity. One hundred and ten new sequences were obtained from the Kemp's ridley turtles from RN sanctuary and compared with the 13 sequences reported in BOLD database. Sequences of nearly 700 bp of Kemp's ridley were aligned among them and compared to 7 different sea turtle species; all new sequences will be added to the BOLD database. Genetic divergence showed a clear separation between other species (0.02 to 0.12), while their relationship with the olive ridley sea turtle (Lepidochelys olivacea) was confirmed (0.02). Also, the result of the haplotype network showed 47 haplotypes, 46 out of which were novel and only one was the most predominant, it belonged to RN sanctuary. The phylogenetic tree showed and confirmed the separation into 2 main clades or families and one out of them, contained the remaining 6 sea turtles species. Finally, DNA barcode for Kemp's ridley was obtained. In conclusion, there was clear evidence that DNA barcode by the COI gene is useful for the study of Kemp's ridley turtles, being able to discriminate between dominant and new haplotypes from those already reported, as well as study phylogeny and genetic diversity in Kemp's ridley.

Antecedentes y Objetivos: La restauración ecológica se ha centrado en los componentes físicos y vegetales de los ecosistemas, y ha dejado de lado a la fauna silvestre y sus interacciones. Chelonia mydas es un macroherbívoro en peligro de extinción que anida en playas de México y Cuba, e influye en la vegetación costera con aportaciones de materia orgánica. Los objetivos de este estudio fueron analizar su recuperación poblacional, un índice del verdor de la vegetación de duna, así como la cantidad de materia orgánica estimada de sus nidadas antes y después de la implementación de una Norma Oficial Mexicana. Métodos: Se analizaron datos de entre dos y tres décadas de monitoreo biológico en 16 playas de anidación de Chelonia mydas; a partir de ellos se realizaron tres niveles de análisis de indicadores demográficos, la aportación de materia orgánica de las tortugas en la playa y el vigor vegetal a partir de sensores remotos, además de aplicar los estadísticos pertinentes. Resultados clave: Hubo un crecimiento exponencial del número de anidaciones de tortuga verde (entre 12 y 14% anual), asociado con pulsos de reclutamiento poblacional en los años 2000 y 2008. El aporte de materia orgánica a la playa fue significativamente mayor después de un cambio en la estrategia para manejo de las nidadas en México, y se detectó un incremento en el verdor de la vegetación de duna en zonas de anidación alta de Chelonia mydas. Conclusiones: El incremento de las poblaciones de tortuga verde lleva a reflexionar acerca de las implicaciones que tiene la recuperación de especies de fauna sobre otras comunidades en los ecosistemas que habitan, lo que demanda el análisis de los paradigmas actuales y la adaptación de estrategias que atiendan sus necesidades de manejo, procurando las condiciones de integridad ecológica de sus hábitats.