The Kemp’s ridley sea turtle, Lepidochelys kempii, is recovering from devastating declines that reduced nesting activity from a single-day estimate of 10,000- 40,000 females in 1947 to fewer than 300 during all of 1985. Nesting beach monitoring is crucial to estimating population size and reproductive activity, but in-water data are essential for understanding population dynamics and evaluating management strategies. Hook-and-line, stranding, and nesting records, satellite telemetry, and diet analyses were used to characterize ridley population dynamics and movements in the northwestern Gulf of Mexico during 2003-2007. Recreational hook-and-line captures comprised approximately one third of non-nesting encounters along Galveston and Jefferson Counties, Texas. The hook-and-line dataset displayed similar geographical and monthly trends to that of strandings, but was devoid of pelagic-stage, subadult, and adult ridleys. Coastal and bay waters along the upper Texas and western Louisiana coasts were utilized by immature ridleys during warmer months. Nesting occurred along Galveston Island on both armored and unarmored beaches. Inter-nesting females exhibited fidelity to Galveston during nesting season and subsequently migrated to federal waters offshore Louisiana. Crabs were important components of benthic-stage (>25 cm SCL) ridley diet, while worm tubes were targeted by some individuals. Short satellite track durations for immature ridleys precipitated examinations of biofouling, attachment protocols, and turtle excluder device (TED) interactions. Antifouling paints drastically reduced fouling of transmitters. A less-rigid neoprene attachment method was developed to increase transmitter retention on fast-growing juveniles, but further trials are necessary. Transmitters were not damaged or lost during TED trials, but turtle escape times increased when transmitters wedged between TED bars. Projected population growth will increase numbers of Kemp’s ridleys utilizing the Gulf of Mexico and interacting with human activities. Future research should examine year-round distribution and abundance of all life history stages and further characterize recreational hook-and-line capture, nesting activity, movements, and diet. Education efforts targeting the beach-going public, beach residents and workers, and the recreational fishing sector should be employed to promote sea turtle reporting and minimize negative interactions. State and federal managers should examine anthropogenic impacts within the region and determine the need for mitigation and/or regulations to promote continued species recovery.

Little is known of trace metal concentrations and their possible role in the mortality of critically endangered Kemp??s ridley sea turtles (Lepidochelys kempii). Research described herein characterized concentrations of seven trace metals ?? Ag, Cd, Cr, Cu, Hg, Pb and Zn ?? in the blood and carapace tissue of captive Kemp??s ridleys for use in assessing levels of these metals in wild counterparts. Concentrations of same trace metals were characterized in post-pelagic through adult life stages of 127 wild Kemp??s ridleys captured from the Gulf of Mexico and southeast Atlantic during 2000 to 2002. Blood, carapace, liver, kidney, and muscle tissues from live and/or stranded Kemp??s ridleys were analyzed for the aforementioned trace metals via graphite furnace atomic absorption spectrophotometer and cold vapor atomic fluorescence techniques conducted under class-100 clean laboratory conditions. Similar trace metal assessments were conducted on blue crab (Callinectes sapidus) prey to determine the role of food as a possible uptake pathway in Kemp??s ridleys. Overall, trace metal levels in live, captive as well as wild ridleys were higher in carapace tissue than in blood. Carapace concentrations of Ag, Cr and Hg in Kemp??s ridleys across all post-pelagic life stages increased with increasing straight carapace length (SCL). Carapace tissue of wild ridleys exhibited higher Cr, Hg, and Pb levels than their blue crab prey, regardless of study area; whereas, crabs yielded higher Ag and Cu concentrations. Dead stranded ridleys yielded higher Ag, Cr, Hg, Pb, Zn levels in carapace tissue, whereas, their liver exhibited higher Cd and Cu levels. This finding suggests carapace tissue could serve as a suitable surrogate sample source for internal organs/tissues when monitoring exposure of live Kemp??s ridleys to certain metals. The fact that larger, stranded ridleys exhibited higher Ag, Cd, Hg, Pb and Zn levels than did their smaller, live analogs from Texas and Louisiana implies that these older ridleys had increased opportunities to accumulate higher metal concentrations in their carapace tissue than did their younger conspecifics. This trend suggests that carapace tissue has the potential to accumulate trace metals while blood-borne concentrations reflect only recent exposure to trace metals.

The critically endangered Kemp's ridley sea turtle experienced a dramatic decline in population size (demographic bottleneck) between 1947 and 1987 from 160,000 mature individuals to less than 5000. Demographic bottlenecks can cause genetic bottlenecks where significant losses of genetic diversity occur through genetic drift. The loss of genetic diversity can lower fitness through the random loss of adaptive alleles and through an increase in the expression of deleterious alleles. Molecular genetic studies on endangered species require collecting tissue using non-invasive or minimally invasive techniques. Such sampling techniques are well developed for birds and mammals, but not for sea turtles. The first objective was to explore the relative success of several minimally invasive tissue-sampling methods as source of DNA from Kemp's ridley sea turtles. Tissue sampling techniques included; blood, cheek swabs, cloacal swabs, carapace scrapings, and a minimally invasive tissue biopsy of the hind flipper. Single copy nuclear DNA loci were PCR amplified with turtle-specific primers. Blood tissue provided the best DNA extractions. Additionally, archival plasma samples are shown to be good sources of DNA. However, when dealing with hatchlings or very small individuals in field situations, the tissue biopsy of the hind flipper is the preferred method. This study's main focus was to evaluate whether the Kemp's ridley sea turtle sustained a measurable loss of genetic variation resulting from the demographic bottleneck. To achieve this goal, three alternative approaches were used to detect a reduction in Kemp's ridley's effective population size (Ne) from microsatellite data. These approaches were 1) Temporal change in allele frequencies, 2)An excess of heterozygotes in progeny, and 3)A mean ratio (M) of the number of alleles (k) to the range of allele size (r). DNA samples were obtained from Kemp's ridleys caught in the wild. PCR was used to amplify eight microsatellite loci and allele frequencies were determined. Data from only four microsatellites could be used. Although the reduced number of loci was a limiting factor in this study, the results of all three approaches suggest that Kemp's ridley sustained a measurable loss of genetic variation due to the demographic bottleneck.

Post-pelagic juvenile and subadult Kemp's ridley sea turtles (Lepidochelys kempii) (20-40 cm straight carapace length) utilize nearshore waters of the northwestern Gulf of Mexico as nursery or developmental feeding grounds. This study utilizes 10 years of entanglement netting data to characterize long-term abundance and distribution of Kemp's ridley sea turtles at index habitats in this region. Netting surveys were conducted during April-October 1993-2002, primarily at Sabine Pass, Texas and Calcasieu Pass, Louisiana. Additionally, this study takes an ecosystem-based approach to understanding factors influencing Kemp's ridley in-water abundance and distribution via the development of a conceptual model incorporating data on nesting dynamics, environmental conditions, prey availability, and predation pressure. Overall monthly mean ridley catch-per-unit-effort (CPUE) peaked in the beginning of summer (April-June), probably in response to rising water temperatures and seasonal occurrence of blue crab prey. Annual mean ridley CPUE across all study areas peaked in 1994, 1997, 1999 and 2002, suggesting a 2-3 year cycle in abundance that may be related to patterns in clutch size or hatch success at the Rancho Nuevo, Mexico nesting beach. However, ridley CPUE in nearshore waters remained relatively constant or decreased slightly even as number of hatchlings released from Rancho Nuevo increased exponentially. Annual declines in Texas strandings since 1994 and subsequent increases in Florida counterparts since 1995 suggest a shift in ridley distribution from the western to eastern Gulf in recent years. Significant declines in ridley CPUE at Sabine Pass since 1997 coincided with a concurrent reduction in blue crab size, but a similar trend was not detected at Calcasieu Pass. Kemp's ridley occurrence at study sites was not significantly related to shrimping activity/by-catch. There also were no biologically significant relationships between Kemp's ridley CPUE and abiotic factors, nor were ridleys deterred from utilizing areas frequented by bull sharks. Overall, nesting dynamics and prey availability were conceptual model components appearing to have the greatest influence on nearshore ridley occurrence.