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Estuarine environments in Florida provide important developmental habitat for sea turtles. We present the first systematic survey of green turtles (Chelonia mydas) inhabiting Lake Worth Lagoon (LWL), a heavily urbanized lagoon in Palm Beach County, Florida. We characterized the distribution, abundance, size class structure, diet, sex ratio, and genetic origin of green turtles in LWL using vessel-based visual transect surveys and captures over the period from 2005 to 2013. Data from 100 captured individuals showed the LWL population was comprised almost entirely of juveniles, with a mean straight standard carapace length of 40.4 centimeters. The distribution of green turtles in LWL coincides with areas where significant submersed aquatic vegetation is present. Dietary analysis from 31 individuals showed that seagrass species comprised 90% of the diet. We also quantified the prevalence and severity of fibropapillomatosis (FP) in the population, a disease associated with impaired water quality. The overall FP prevalence for the population was 48.7%, and both prevalence and severity of FP appear to be stable or slightly increasing over the period from 2005-2013. Long-term monitoring of this population may serve to provide an important barometer of overall lagoon health, and assess the progress of ongoing efforts in lagoon restoration. [ABSTRACT FROM AUTHOR]

In order to provide information to better inform management decisions and direct further research, vessel-based visual transects, snorkel transects, and in-water capture techniques were used to characterize hawksbill sea turtles in the shallow marine habitats of a Marine Protected Area (MPA), the Key West National Wildlife Refuge in the Florida Keys. Hawksbills were found in hardbottom and seagrass dominated habitats throughout the Refuge, and on man-made rubble structures in the Northwest Channel near Cottrell Key. Hawksbills captured (N = 82) were exclusively juveniles and subadults with a straight standard carapace length (SSCL) ranging from 21.4 to 69.0cm with a mean of 44.1 cm (SD = 10.8). Somatic growth rates were calculated from 15 recaptured turtles with periods at large ranging from 51 to 1188 days. Mean SSCL growth rate was 7.7 cm/year (SD = 4.6). Juvenile hawksbills (<50 cm SSCL) showed a significantly higher growth rate (9.2 cm/year, SD = 4.5, N = 11) than subadult hawksbills (50–70 cm SSCL, 3.6 cm/year, SD = 0.9, N = 4). Analysis of 740 base pair mitochondrial control region sequences from 50 sampled turtles yielded 12 haplotypes. Haplotype frequencies were significantly different compared to four other Caribbean juvenile foraging aggregations, including one off the Atlantic coast of Florida. Many-to-one mixed stock analysis indicated Mexico as the primary source of juveniles in the region and also suggested that the Refuge may serve as important developmental habitat for the Cuban nesting aggregation. Serum testosterone radioimmunoassay results from 33 individuals indicated a female biased sex ratio of 3.3 females: 1 male for hawksbills in the Refuge. This assemblage of hawksbills is near the northern limit of the species range, and is one of only two such assemblages described in the waters of the continental United States. Since this assemblage resides in an MPA with intensive human use, basic information on the assemblage is vital to resource managers charged with conservation and species protection in the MPA. [ABSTRACT FROM AUTHOR]

Objective-To determine reference intervals for concentrations of plasma total protein (TP) and electrophoretogram fractions (ELFs) for healthy, wild loggerhead sea turtles (Caretta caretta) and green turtles (Chelonia mydas) and to assess relationships betweenTP and ELF concentrations and health status, body size, body mass, and water temperature. Design-Evaluation study. Animals-437 healthy and 35 ill Atlantic loggerhead sea turtles and 152 healthy and 3 ill Atlantic green turtles. Procedures-Free-ranging turtles were captured from a nuclear power plant intake canal in southern Florida. Plasma samples were obtained from all turtles. Plasma IF and ELF concentrations were measured, and reference intervals were calculated. Wilcoxon rank-sum tests were used to compare TP and ELF values between healthy and ill loggerhead sea turtles. Spearman rank correlations were evaluated between concentrations of TP and ELFs and carapace length, body mass, and water temperature. Results-Reference intervals for TP concentrations were 2.2 to 5.2 gdL and 2.0 to 5.4 g/dL for loggerhead sea turtles and green turtles, respectively. Except for γ-globulin, concentrations of ELFs were significantly higher in healthy than in ill loggerhead sea turtles. There was a positive correlation between TP, α-globulin, β-globulin, and γ-globulin concentrations and water temperature in loggerhead sea turtles and between only IF and a-globulin concentrations and water temperature in green turtles. Conclusions and Clinical Relevance-Reference intervals for concentrations of IF and ELFs for healthy, free-ranging loggerhead sea turtles and green turtles can be used in combination with other diagnostic tools to assess health status of sea turtles. [ABSTRACT FROM AUTHOR]

The article focuses on tracking the nesting migration of the critically endangered Kemp's Ridley Sea Turtle (Lepidochelys kempii), highlighting its predominant nesting areas along the western Gulf of Mexico coast and the identification of key foraging areas.

Natural biotoxins and anthropogenic toxicants pose a significant risk to sea turtle health. Documented effects of contaminants include potential disease progression and adverse impacts on development, immune function, and survival in these imperiled species. The shallow seagrass habitats of Florida's northwest coast (Big Bend) serve as an important developmental habitat for Kemp's ridley ( Lepidochelys kempii ) and green ( Chelonia mydas ) sea turtles; however, few studies have been conducted in this area. Our objectives were (1) to evaluate plasma analytes (mass, minimum straight carapace length, body condition index [BCI], fibropapilloma tumor score, lysozyme, superoxide dismutase, reactive oxygen/nitrogen species, plasma protein electrophoresis, cholesterol, and total solids) in Kemp's ridleys and green turtles and their correlation to brevetoxins that were released from a red tide bloom event from July–October 2014 in the Gulf of Mexico near Florida's Big Bend, and (2) to analyze red blood cells in Kemp's ridleys and green turtles for toxic elements (arsenic, cadmium, lead, mercury, selenium, thallium) with correlation to the measured plasma analytes. Positive correlations were observed between brevetoxins and α 2 -globulins in Kemp's ridleys and α 2 - and γ-globulins in green turtles, indicating potential immunostimulation. Arsenic, cadmium, and lead positively correlated with superoxide dismutase in Kemp's ridleys, suggesting oxidative stress. Lead and mercury in green turtles negatively correlated with BCI, while mercury positively correlated with total tumor score of green turtles afflicted with fibropapillomatosis, suggesting a possible association with mercury and increased tumor growth. The total tumor score of green turtles positively correlated with total protein, total globulins, α 2 -globulins, and γ-globulins, further suggesting inflammation and immunomodulation as a result of fibropapillomatosis. Lastly, brevetoxin concentrations were positively related to tumor score, indicating potential tumor promotion by brevetoxin. These results signify that brevetoxins and toxic elements elicit various negative effects on sea turtle health, including immune function, oxidative stress, and possibly disease progression. [ABSTRACT FROM AUTHOR]

Somatic growth is an integrated, individual-based response to environmental conditions, especially in ectotherms. Growth dynamics of large, mobile animals are particularly useful as bio-indicators of environmental change at regional scales. We assembled growth rate data from throughout the West Atlantic for green turtles, Chelonia mydas, which are long-lived, highly migratory, primarily herbivorous mega-consumers that may migrate over hundreds to thousands of kilometers. Our dataset, the largest ever compiled for sea turtles, has 9690 growth increments from 30 sites from Bermuda to Uruguay from 1973 to 2015. Using generalized additive mixed models, we evaluated covariates that could affect growth rates; body size, diet, and year have significant effects on growth. Growth increases in early years until 1999, then declines by 26% to 2015. The temporal (year) effect is of particular interest because two carnivorous species of sea turtles-hawksbills, Eretmochelys imbricata, and loggerheads, Caretta caretta-exhibited similar significant declines in growth rates starting in 1997 in the West Atlantic, based on previous studies. These synchronous declines in productivity among three sea turtle species across a trophic spectrum provide strong evidence that an ecological regime shift ( ERS) in the Atlantic is driving growth dynamics. The ERS resulted from a synergy of the 1997/1998 El Niño Southern Oscillation ( ENSO)-the strongest on record-combined with an unprecedented warming rate over the last two to three decades. Further support is provided by the strong correlations between annualized mean growth rates of green turtles and both sea surface temperatures ( SST) in the West Atlantic for years of declining growth rates ( r = −.94) and the Multivariate ENSO Index ( MEI) for all years ( r = .74). Granger-causality analysis also supports the latter finding. We discuss multiple stressors that could reinforce and prolong the effect of the ERS. This study demonstrates the importance of region-wide collaborations. [ABSTRACT FROM AUTHOR]

In response to a call from the US National Research Council for research programs to combine their data to improve sea turtle population assessments, we analyzed somatic growth data for Northwest Atlantic (NWA) loggerhead sea turtles ( Caretta caretta) from 10 research programs. We assessed growth dynamics over wide ranges of geography (9-33°N latitude), time (1978-2012), and body size (35.4-103.3 cm carapace length). Generalized additive models revealed significant spatial and temporal variation in growth rates and a significant decline in growth rates with increasing body size. Growth was more rapid in waters south of the USA (<24°N) than in USA waters. Growth dynamics in southern waters in the NWA need more study because sample size was small. Within USA waters, the significant spatial effect in growth rates of immature loggerheads did not exhibit a consistent latitudinal trend. Growth rates declined significantly from 1997 through 2007 and then leveled off or increased. During this same interval, annual nest counts in Florida declined by 43 % (Witherington et al. in Ecol Appl 19:30-54, ) before rebounding. Whether these simultaneous declines reflect responses in productivity to a common environmental change should be explored to determine whether somatic growth rates can help interpret population trends based on annual counts of nests or nesting females. Because of the significant spatial and temporal variation in growth rates, population models of NWA loggerheads should avoid employing growth data from restricted spatial or temporal coverage to calculate demographic metrics such as age at sexual maturity. [ABSTRACT FROM AUTHOR]

Ozobranchus margoi and Ozobranchus branchiatus are the only two species of marine turtle leeches ( Ozobranchus spp.) known to inhabit the Atlantic coast of the United States and the Gulf of Mexico. In early reports of fibropapillomatosis (FP) in green turtles ( Chelonia mydas), O. branchiatus was implicated as a vector in the transmission of Fibropapilloma-associated turtle herpesvirus (FPTHV). It is imperative that the leech species be identified to elucidate the role Ozobranchus spp. may play in disease transmission. In this study, Ozobranchus branchiatus has been identified for the first time on a loggerhead ( Caretta caretta) turtle, and the molecular data for this species is now available for the first time in GenBank. Both species of leeches were also found infecting a single C. mydas. Using morphological taxonomy combined with distance- and character-based genetic sequence analyses, this study has established a DNA barcode for both species of Ozobranchus spp. leech and has shown it can be applied successfully to the identification of leeches at earlier stages of development when morphological taxonomy cannot be employed. The results suggest a different haplotype may exist for O. branchiatus leeches found on C. caretta versus C. mydas. Leech cocoon residue collected from a C. mydas was identified using the new method. [ABSTRACT FROM AUTHOR]

Simple Summary: Sea turtles are susceptible to several herpesviruses that are linked to dermatologic diseases, including fibropapillomatosis (FP) and lung-eye-trachea disease. Aside from obvious skin lesions, a number of other sublethal impacts occur in response to these diseases, such as reduced immune function. In this study, we found no relationship between disease presence or severity and T-cell proliferation in green turtles from Florida, USA, at least until the moderate stages of FP; however, natural killer cell activity, a measure of innate immune function, was significantly reduced in turtles with FP compared to tumor-free individuals. This is the first study to examine natural killer cell activity in relation to FP, improving upon our understanding of altered immune system function associated with this disease. Chelonid alphaherpesviruses 5 and 6 (ChHV5 and ChHV6) are viruses that affect wild sea turtle populations. ChHV5 is associated with the neoplastic disease fibropapillomatosis (FP), which affects green turtles (Chelonia mydas) in panzootic proportions. ChHV6 infection is associated with lung-eye-trachea disease (LETD), which has only been observed in maricultured sea turtles, although antibodies to ChHV6 have been detected in free-ranging turtles. To better understand herpesvirus prevalence and host immunity in various green turtle foraging aggregations in Florida, USA, our objectives were to compare measures of innate and adaptive immune function in relation to (1) FP tumor presence and severity, and (2) ChHV5 and ChHV6 infection status. Free-ranging, juvenile green turtles (N = 45) were captured and examined for external FP tumors in Florida's Big Bend, Indian River Lagoon, and Lake Worth Lagoon. Blood samples were collected upon capture and analyzed for ChHV5 and ChHV6 DNA, antibodies to ChHV5 and ChHV6, in vitro lymphocyte proliferation using a T-cell mitogen (concanavalin A), and natural killer cell activity. Despite an overall high FP prevalence (56%), ChHV5 DNA was only observed in one individual, whereas 20% of turtles tested positive for antibodies to ChHV5. ChHV6 DNA was not observed in any animals and only one turtle tested positive for ChHV6 antibodies. T-cell proliferation was not significantly related to FP presence, tumor burden, or ChHV5 seroprevalence; however, lymphocyte proliferation in response to concanavalin A was decreased in turtles with severe FP (N = 3). Lastly, green turtles with FP (N = 9) had significantly lower natural killer cell activity compared to FP-free turtles (N = 5). These results increase our understanding of immune system effects related to FP and provide evidence that immunosuppression occurs after the onset of FP disease. [ABSTRACT FROM AUTHOR]