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Sea turtles suffer from numerous threats such as predation, tidal inundation, and coastal building. We aimed to assess the effectiveness of hatchery technique on Göksu Delta beach, Turkey during the nesting season of 2010. For this purpose, eggs of loggerhead turtle (Caretta caretta) nests under the risk of tidal inundation were transferred into two protected hatchery sites that were constructed on Göksu Delta beach, in which there were no risk of predation and inundation, and the other nests were left to remain in situ. Hatching success of hatchery and natural nests were calculated. In addition, temperatures of both hatchery and natural nests (5 and 6 nests, respectively) were recorded, and sex ratios were determined using these nest temperatures and incubation periods. It was determined that hatching success increased with increasing distance from the sea (until 31 m) (r2 = 0.98), increasing incubation period (up to 60 days) (r2 = 0.68), and decreasing clutch size (r2 = 0.93), implying that the production of male hatchling is high in a nest if hatching success of that nest is high (or vice versa). Mean hatching success, incubation period, and nest temperature for hatchery nests were found to be 72.8%, 51.1 days, and 30.2 °C, respectively, while the corresponding values for natural nests were found to be 40.5%, 49.9 days, and 31.1 °C, respectively. It was also detected that hatchery nests produced higher proportion of male hatchlings (25.2%) compared with natural nests (13.5%). Based on all these results, it can be concluded that hatchery management on this beach is not a completely effective conservation technique. Nest relocation and/or hatchery management enable the conservationists to increase hatching success rate, but they cause sex ratio alteration. In this respect, we can only partially support nest relocation and/or hatchery management. They should be considered as a last option due to sex ratio alteration. © 2017 Elsevier Ltd more...

With the aim of evaluating the presence of Fusarium spp. in sea turtles with and without lesions and assessing the risk factors favoring colonization and/or infection, 74 loggerhead sea turtles ( Caretta caretta) admitted to rescue and rehabilitation clinics in Italy were analyzed. The study compared 31 individuals with no apparent macroscopic lesions and 43 individuals with macroscopic lesions. Shell and skin samples were analyzed using Calcofluor white with 10% potassium hydroxide, standard histopathological examination, and fungal cultures. Fusarium spp. were isolated more frequently from animals with superficial lesions (39%) than from those with no macroscopic lesions (16%). Isolates from animals with superficial lesions were Fusarium solani species complex (FSSC) lineages haplotypes 9, 12, and 27 (unnamed lineages), FSSC-2 ( Fusarium keratoplasticum), Fusarium oxysporum (27%), and Fusarium brachygibbosum (3%). In contrast, only F. solani haplotypes 9 and 12 were isolated from animals with no macroscopic lesions. The presence of lesions was identified as a risk factor for the occurrence of Fusarium spp. Of the 74 animals, only 7 (9.5%) scored positive on microscopic examination with Calcofluor, and histological examination of those 7 animals revealed necrosis, inflammatory cells, and fungal hyphae in the carapace and skin. The results of this study suggest that fusariosis should be included in the differential diagnosis of shell and skin lesions in sea turtles. Direct examination using Calcofluor and potassium hydroxide was not useful to diagnose the infection. Histopathological examination and fungal culture should be performed to ensure correct treatment and infection control. more...

Epizoic diatoms form an important part of micro-epibiota of marine vertebrates such as whales and sea turtles. The present study explores and compares the diversity and biogeography of diatom communities growing on the skin and shell of loggerhead sea turtles (Caretta caretta) from four different localities: Adriatic Sea (Croatia), Ionian Sea (Greece), South Africa and Florida Bay (USA) using both light and scanning electron microscopy. We observed almost 400 diatom taxa belonging to more than 100 genera. Diatom communities from Greece and Croatia showed the highest similarity and were statistically different from those recorded from South Africa and Florida. Part of this variation could be attributed to differences in sampling techniques; however, we believe that geography had an important role. In general, contrary to several previous observations from sea turtles, the presumably exclusively epizoic diatoms contributed less than common benthic taxa to the total diatom flora, which might have been related to the loggerhead feeding behavior. Moreover, skin samples differed from carapace samples in having a distinct diatom composition with a higher proportion of the putative true epizoonts. Our results indicate that epizoic diatom communities differ according to loggerhead geographical location and substrate (skin vs. carapace). The relative abundances of common benthic diatoms and putative exclusive epizoic taxa may inform about sea turtle habitat use or behavior though detailed comparisons among different host species have yet to be performed. more...

Mercury has been identified as one of the most serious environmental threats to the well-being of wildlife in the southeastern United States (Facemire et al. 1995). The prevalence of Hg in aquatic species has also prompted concerns for the health of subsistence fishermen and the general population who regularly consume fish. This concern is evident in the fact that 76% of fish consumption advisories in the United States in 2003 were due at least in part to Hg, for a total of 5,289,020 hectares of lakes and 1,234,127 river miles [U.S. Environmental Protection Agency (EPA) 2004]. The toxic effects of Hg have been demonstrated in mammals, birds, and fish and include neurotoxicity, impaired growth and development, reduced reproductive success, liver and kidney damage, and immunomodulation (Wiener et al. 2003; Zelikoff et al. 1994). Reptiles are prominent members of ecosystems and often have life history characteristics that make them vulnerable to Hg accumulation (e.g., long life span, high trophic level, aquatic habitat). Despite the fact that many of these reptilian species also have a tenuous conservation status, there are currently few data on the toxicity of Hg in this taxon. One such example is the sea turtle, of which all species are classified as either threatened or endangered. Many anthropogenic factors have been implicated in the decline in sea turtle populations, including directed harvest for food and trade, fisheries bycatch, and degradation of nesting beach habitat (Lutcavage et al. 1997). However, the role of chemical pollutants in marine turtle health is largely unknown. It is therefore important to understand the risk that contaminants pose to the general health and immunologic function of sea turtles because these effects could also impact the survival of their populations. Several studies have measured Hg levels in tissues from juvenile and adult sea turtles (Anan et al. 2001; Davenport and Wrench 1990; Day et al. 2005; Godley et al. 1999; Gordon et al. 1998; Maffucci et al. 2005; Orvik 1997; Presti 1999; Sakai et al. 1995, 2000a, 2000b; Storelli et al. 1998, 2005; Wang 2005). However, relatively few studies have assessed health parameters in sea turtles in relation to environmental contaminants (Keller et al. 2004, 2005, 2006a, 2006b; Lutcavage et al. 1995; Peden-Adams et al. 2002, 2003; Podreka et al. 1998), and these studies have focused primarily on organic contaminants rather than metals. Balazs and Pooley (1991) suggested that environmental contaminants are a possible factor contributing to the development of the viral disease fibropapillomatosis in sea turtles by reducing immune function. Some locations in Florida (Indian River Lagoon and Florida Bay) exhibit up to 70% prevalence of this disease, and these environments also have elevated levels of Hg (Ache et al. 2000; Cantillo et al. 1999; Trocine and Trefry 1996). In the present study we investigated the relationship of blood Hg levels in loggerhead sea turtles (Caretta caretta) off the coasts of South Carolina, Georgia, and northern Florida to various immunologic and general health parameters. Using an integrated approach, correlative field data collection from wild-caught loggerhead sea turtles were combined with laboratory in vitro exposure of loggerhead lymphocytes to methylmercury (MeHg). more...

The helminth fauna of pelagic-stage loggerhead sea turtles, Caretta caretta, is still poorly known. Here, we describe the helminth-component community of healthy, free-ranging juvenile loggerhead sea turtles captured in the waters around Madeira Island, Portugal. Fifty-seven were used in this study. The esophagus, stomach, intestine, liver, gallbladder, spleen, kidneys, trachea, bronchi, urinary bladder, heart, left and right aortas, and coelomic cavity were macroscopically inspected; organs and tissues were removed and washed through a sieve. A search for parasites was made using a stereoscopic microscope; recovered parasites were fixed and stored in 70% alcohol until staining and identification. Prevalence, mean intensity, and mean abundance values were recorded. In total, 156 parasite specimens belonging to 9 species were found: nematodes included Anisakis simplex s.l. (larvae) and an unidentified species; digenetic trematodes present were Enodiotrema megachondrus, Rhytidodes gelatinosus, Pyelosomum renicapite, and Calycodes anthos; acanthocephalans included Bolbosoma vasculosum and Rhadinorhynchus pristis; a single cestode, Nybelinia sp., was present. Parasite infections were found to have both low prevalences and intensities. Possible reasons for this include the oligotrophic conditions of the pelagic habitat around Madeira; a 'dilution effect' because of the vastness of the area; and the small size, and thus ingestion rate, of the turtles. Results are discussed in terms of the various turtle populations that may use the waters surrounding Madeira. This work provides valuable information on the parasite fauna of a poorly known stage in the life of loggerhead sea turtles, thereby filling a fundamental gap with regard to features of the parasite fauna in this species. more...

Researchers compared nest architecture in loggerhead sea turtles at natural beaches in Florida, USA and Brazil to determine how similarities and differences in female morphology and reproductive output in these two populations are reflected in the structure of the nest. more...

Loggerhead sea turtles (Caretta caretta) nest in numerous substrate and beachtypes within the Ten Thousand Islands (TTl) of southwest Florida. Nesting beachselection was analyzed on 12 islands within this archipelago. Numerous physicalcharacteristics were recorded to identify the relatedness of these variables and determinetheir importance for nesting beach selection in C. caretta. These variables were chosenafter evaluating the islands, conducting literature searches and soliciting personalcommunications. Along transects, data were collected, on the following: height ofcanopy, beach width, overall slope (beach slope and slope of offshore approach) and sandsamples analyzed for pH, percentage of water, percentage of organic content, percentageof carbonate and particle size (8 size classes). Data on ordinal aspect of beaches andbeach length were also recorded and included in the analysis. All of the variables wereanalyzed by tree regression, incorporating the nesting data into the analysis. In the TTl,loggerheads appear to prefer wider beaches (p< 0.001; R2= 0.56) that inherently have lessslope, and secondarily, wider beaches that have low amounts of carbonate (p< O.00 1). Inaddition, C. caretta favors nest sites within or in close proximity to the supra-littoralvegetation zone of beaches in the TTl (p< 0.001). (86 page document) Completed for U.S. Fish and Wildlife Service & National Park Service more...

Plastic pollution is nowadays a relevant threat for the ecological balance in marine ecosystems. Small plastic debris (PD) can enter food webs through various marine organisms, with possible consequences on their physiology and health. The loggerhead sea turtle (Caretta caretta), widespread across the whole Mediterranean Sea, is a “flagship species,” useful as indicator of the general pollution level of marine ecosystems. Ingested PD accumulate in the final section of turtles’ digestive tract before excretion. During their transit and accumulation, PD also interact with the residing microbial community, with possible feedback consequences on the host’s health. To explore the possible relationship between fecal microbial composition and PD ingestion, we collected fecal samples from 45 turtles rescued between 2017 and 2019 in the Northwestern Adriatic Sea (Italy), assessing occurrence and content of PD in the samples and in parallel the microbiome structure by 16S rRNA gene sequencing. According to our findings, almost all samples contained PD, mirroring the high level of plastic pollution in the area. We identified phylotypes associated to a high amount of PD, namely Cetobacterium somerae and other taxa, possibly responding to contamination by plastic-associated chemicals. Furthermore, putative marine pathogens were found associated to higher plastic contamination, supporting the hypothesis that PD can act as a carrier for environmental pathogenic bacteria into marine organisms. Besides confirming the role of the sea turtle as relevant flagship species for plastic pollution of the marine environment, our study paves the way to the exploration of the impact that PD ingestion can have on the microbial counterpart of large marine organisms, with potential feedback consequences on the animal and ecosystem health. more...