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Sea Turtles (sea + turtle)
Kinds of Sea Turtles Selected AbstractsCT and Cross-sectional Anatomy of the Normal Head of the Loggerhead Sea Turtle (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005A. Arencibia The objective of this study is to describe the CT anatomy of the normal loggerhead sea turtle (Caretta caretta) head using three loggerhead sea turtle heads. CT imaging was performed using the following parameters: K.v.: 120 mAs: 220, and a soft-tissue window (WW 1880, WL 465): Transverse and sagittal CT images were obtained. Detailed anatomy of the head was acquired with the sagittal and transverse series. The heads were frozen and then sectioned using an electric saw, to compare them with the CT images. In CT, the grey scale is directly related to the radiation attenuation of the head structures. The skull and hyoid bones, and the lower jaw were easily identifiable due to the high CT density image compared to adjacent or surrounding structures such as the respiratory system, oral cavity, oesophagus and cranial cavity that appeared as a low opacity. The nervous structures, salt gland, eyeball, ramphoteca structure and different muscles of the head had an intermediate CT density and appeared grey. CT images of the loggerhead sea turtle head provided excellent detail of clinically relevant anatomy and correlated well with corresponding gross specimens. CT of the head has considerable advantages over other techniques: CT provides excellent spatial resolution and good discrimination between bone and soft tissue, and the structures are viewed without superimposition. The planimetric or sectional anatomy of the head allows a correct morphologic and topographic evaluation of the anatomic structures, which is a useful tool for the identification of the CT images. With developing technology, CT imaging may soon become more readily available for exotic animals imaging. In the same way, we consider it quite useful to be able to establish some references on head, in order to scan only selected parts during a clinical or experimental approach. The information presented in this communication should serve as an initial reference to evaluate CT images of the loggerhead sea turtle head and to assist interpretation of lesions of this region. [source] Ultrastructural Characteristics of Blood Cells of Juvenile Loggerhead Sea Turtles (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2007A. B. Casal Summary Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species. [source] Dispersal, recruitment and migratory behaviour in a hawksbill sea turtle aggregationMOLECULAR ECOLOGY, Issue 3 2008XIMENA VELEZ-ZUAZO Abstract We investigated the dispersal, recruitment and migratory behaviour of the hawksbill sea turtle (Eretmochelys imbricata), among different life-history stages and demographic segments of the large hawksbill turtle aggregation at Mona Island, Puerto Rico. There were significant differences in both mitochondrial DNA (mtDNA) haplotype diversity and haplotype frequencies among the adult males, females and juveniles examined, but little evidence for temporal heterogeneity within these same groups sampled across years. Consistent with previous studies and the hypothesis of strong natal homing, there were striking mtDNA haplotype differences between nesting females on Mona Island and nesting females in other major Caribbean rookeries. Breeding males also showed strong, albeit weaker, genetic evidence of natal homing. Overall, Bayesian mixed-stock analysis suggests that Mona Island was the natal rookery for 79% (65,94%) of males in the aggregation. In contrast, the Mona Island rookery accounted for only a small subset of the new juvenile recruits to the foraging grounds or in the population of older juvenile hawksbills turtles on Mona. Instead, both new recruits and the older juvenile hawksbill turtles on Mona more likely recruited from other Caribbean rookeries, suggesting that a mechanism besides natal homing must be influencing recruitment to feeding habitats. The difference in the apparent degree of natal homing behaviour among the different life-history stages of hawksbill turtles at Mona Island underscores the complexity of the species' life-history dynamics and highlights the need for both local and regional conservation efforts. [source] Characterization of single nucleotide polymorphism markers for the green sea turtle (Chelonia mydas)MOLECULAR ECOLOGY RESOURCES, Issue 3 2009SUZANNE E. RODEN Abstract We present data on 29 new single nucleotide polymorphism assays for the green sea turtle, Chelonia mydas. DNA extracts from 39 green turtles were used for two methods of single nucleotide polymorphism discovery. The first approach employed an amplified fragment length polymorphism technique. The second technique screened a microsatellite library. Allele-specific amplification assays were developed for high-throughput single nucleotide polymorphism genotyping and tested on two Pacific C. mydas nesting populations. Observed heterozygosities ranged from 0 to 0.95 for a Hawaiian population and from 0 to 0.85 for a Galapagos population. Each of the populations had one locus out of Hardy,Weinberg equilibrium, SSCM2b and SSCM5 for Hawaii and Galapagos, respectively. No loci showed significant genotypic linkage disequilibrium across an expanded set of four Pacific nesting populations. However, two loci, SSCM4 and SSCM10b showed linkage disequilibrium across three populations indicating possible association. [source] Tetranucleotide microsatellites from the loggerhead sea turtle (Caretta caretta)MOLECULAR ECOLOGY RESOURCES, Issue 5 2007BRIAN M. SHAMBLIN Abstract We describe primers and polymerase chain reaction conditions to amplify 15 tetranucleotide microsatellite loci from the loggerhead sea turtle (Caretta caretta). The primers were tested on 30 individuals that nested along the Georgia, USA coast. The primer pairs developed in this study yielded an average of 13.9 alleles per locus (range of 10,21), an average observed heterozygosity of 0.91 (range 0.79,1.00), and an average polymorphic information content of 0.88 (range 0.84,0.92). [source] Development and characterization of novel microsatellite markers from the olive ridley sea turtle (Lepidochelys olivacea)MOLECULAR ECOLOGY RESOURCES, Issue 1 2004Ramesh K. Aggarwal Abstract Olive ridley turtles, although widely distributed globally and in Indian coastal waters, have undergone declines in recent years due to anthropogenic factors, particularly fishery-related mortality. Assessment of genetic variability in existing populations is critical to the development of effective conservation strategies. Here we describe the development of six highly polymorphic microsatellite loci from a simple sequence repeat-enriched genomic DNA library of olive ridley turtle. Characterization of five of these loci using 83 individual olive ridley turtles revealed eight to 24 alleles per locus, high observed and expected heterozygosity values and broad cross-species amplifications. The sixth microsatellite was found to be monomorphic in the olive ridley samples but was polymorphic in two related marine turtle species. These microsatellites thus provide efficient genetic markers to understand the population structure, phylogeography and species relationships of olive ridley and other marine turtle species. [source] Unfolding of the loggerhead sea turtle (Caretta caretta) myoglobin: A 1H-NMR and electronic absorbance studyPROTEIN SCIENCE, Issue 9 2002Daniela Delli Castelli Abstract The effect of urea concentration on the backbone solution structure of the cyanide derivative of ferric Caretta caretta myoglobin (at pH 5.4) is reported. By addition of urea, sequential and long-range nuclear Overhauser effects (NOEs) are gradually lost. By using the residual NOE constraints to build the molecular model, a picture of the unfolding pathway was obtained. When the urea concentration is raised to 2.2 M, helices A and B appear largely disordered; helices C, D, and F loose structural constraints at 3.0 M urea. At urea concentration >6 M, the protein appears to be fully unfolded, including the GH hairpin and helix E stabilizing the prosthetic group. Reversible and cooperative denaturation isotherms obtained by following NOE peaks are considerably different from those obtained by monitoring electronic absorption changes. The reversible and cooperative urea-dependent folding-unfolding process of C. caretta myoglobin follows the minimum three-state mechanism N,X,D, where X represents a disordered globin structure (occurring at ,4 M urea) that still binds the heme. [source] Ultrastructural Characteristics of Blood Cells of Juvenile Loggerhead Sea Turtles (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2007A. B. Casal Summary Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species. [source] CT and Cross-sectional Anatomy of the Normal Head of the Loggerhead Sea Turtle (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 2005A. Arencibia The objective of this study is to describe the CT anatomy of the normal loggerhead sea turtle (Caretta caretta) head using three loggerhead sea turtle heads. CT imaging was performed using the following parameters: K.v.: 120 mAs: 220, and a soft-tissue window (WW 1880, WL 465): Transverse and sagittal CT images were obtained. Detailed anatomy of the head was acquired with the sagittal and transverse series. The heads were frozen and then sectioned using an electric saw, to compare them with the CT images. In CT, the grey scale is directly related to the radiation attenuation of the head structures. The skull and hyoid bones, and the lower jaw were easily identifiable due to the high CT density image compared to adjacent or surrounding structures such as the respiratory system, oral cavity, oesophagus and cranial cavity that appeared as a low opacity. The nervous structures, salt gland, eyeball, ramphoteca structure and different muscles of the head had an intermediate CT density and appeared grey. CT images of the loggerhead sea turtle head provided excellent detail of clinically relevant anatomy and correlated well with corresponding gross specimens. CT of the head has considerable advantages over other techniques: CT provides excellent spatial resolution and good discrimination between bone and soft tissue, and the structures are viewed without superimposition. The planimetric or sectional anatomy of the head allows a correct morphologic and topographic evaluation of the anatomic structures, which is a useful tool for the identification of the CT images. With developing technology, CT imaging may soon become more readily available for exotic animals imaging. In the same way, we consider it quite useful to be able to establish some references on head, in order to scan only selected parts during a clinical or experimental approach. The information presented in this communication should serve as an initial reference to evaluate CT images of the loggerhead sea turtle head and to assist interpretation of lesions of this region. [source] Effects of Coastal Lighting on Foraging Behaviorof Beach MiceCONSERVATION BIOLOGY, Issue 5 2004BRITTANY L. BIRD comportamiento de forrajeo; iluminación artificial; polución por luz; ratones de playa (Peromyscus polionotus leucocephalus) Abstract:,Introduction of artificial light into wildlife habitat represents a rapidly expanding form of human encroachment, particularly in coastal systems. Light pollution alters the behavior of sea turtles during nesting; therefore, long-wavelength lights,low-pressure sodium vapor and bug lights,that minimize impacts on turtles are required for beach lighting in Florida (U.S.A.). We investigated the effects of these two kinds of lights on the foraging behavior of Santa Rosa beach mice ( Peromyscus polionotus leucocephalus). We compared patch use and giving-up densities of mice for experimental food patches established along a gradient of artificial light in the field. Mice exploited fewer food patches near both types of artificial light than in areas with little light and harvested fewer seeds within patches near bug lights. Our results show that artificial light affects the behavior of terrestrial species in coastal areas and that light pollution deserves greater consideration in conservation planning. Resumen:,La introducción de luz artificial al hábitat de vida silvestre representa una forma de intrusión humana que se expande rápidamente, particularmente en sistemas costeros. Durante la anidación, la polución por luz altera el comportamiento de tortugas marinas; por tanto, para la iluminación de playas en Florida (E. U. A) se requieren luces de longitud de onda larga , luces de vapor de sodio de baja presión y contra insectos , que minimizan impactos sobre las tortugas. Investigamos los efectos de estos dos tipos de luces sobre el comportamiento de forrajeo de ratones de playa de Santa Rosa ( Peromyscus polionotus leucocephalus). Comparamos el uso de parches y las densidades de rendición de ratones en parches alimenticios experimentales establecidos a lo largo de un gradiente de luz artificial en el campo. Los ratones utilizaron menos parches de forrajeo cercanos a ambos tipos de luz artificial que en áreas con poca iluminación y cosecharon menos semillas en parches cercanos a luces contra insectos. Nuestros resultados muestran que la luz artificial afecta el comportamiento de especies terrestres en áreas costeras y que la polución por luz merece mayor consideración en la planificación de la conservación. [source] Organochlorine contaminants in sea turtles: Correlations between whole blood and fatENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 3 2004Jennifer M. Keller Abstract Monitoring toxic organochlorine(OC)compounds is an important aspect in wildlife studies, especially in protected species such as sea turtles. The goal of this study was to determine whether blood OC concentrations can predict those in adipose tissue of sea turtles. Blood offers many benefits for monitoring OCs. It can be collected nondestructively from live turtles and can be sampled repeatedly for continuous monitoring. Organochlorine concentrations in blood may better represent the exposure levels of target tissues, but blood concentrations may fluctuate more than those in fatty tissues following recent dietary exposure or lipid mobilization. Paired fat and blood samples were collected from 44 live, juvenile loggerhead sea turtles and 10 juvenile Kemp's ridley sea turtle carcasses. Organochlorines were analyzed using gas chromatography with electron capture detection and mass spectrometry. Lipid-normalized OC concentrations measured in the blood significantly correlated to levels found in the fat samples of both species. This result suggests that sea turtle blood is a suitable alternative to fatty tissues for measuring OCs because blood concentrations reasonably represent those observed in the paired fat samples. However, blood OC concentrations calculated on a wet-mass basis were significantly and inversely correlated to lipid content in the fat samples. Therefore, caution should be used when monitoring spatial or temporal trends, as OC levels may increase in the blood following mobilization of fat stores, such as during long migrations, breeding, or disease events. [source] Occurrence of several arsenic compounds in the liver of birds, cetaceans, pinnipeds, and sea turtlesENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 6 2003Reiji Kubota Abstract Concentrations of total arsenic and individual arsenic compounds were determined in livers of birds, cetaceans, pinnipeds, and sea turtles by using hydride generation-atomic absorption spectrometry and high-performance liquid chromatography/inductively coupled plasma-mass spectrometry. Hepatic arsenic concentrations in loggerhead turtles (11.2 ± 3.0 ,g/g dry wt) and black-footed albatrosses (12.2 ± 10.8 ,g/g dry wt) were extremely high among the species examined, and the values were comparable with those of lower trophic marine animals such as fishes, cephalopods, crustaceans, and shellfishes. In all the species, arsenobetaine was the predominant arsenic compound in the livers. Especially, for black-footed albatrosses and black-tailed gull, the mean percentage of arsenobetaine was as high as 97.1 and 87.5, respectively, of extractable arsenic. The present study is among the first on arsenic speciation in avian species. Total arsenic concentration was strongly correlated with the concentration of arsenobetaine, while no significant relationship was observed between total arsenic concentration and other arsenic compounds in these animals. Because arsenobetaine is known to be rapidly excreted into the urine in humans and experimental animals, the observed results suggest that higher trophic marine animals might have a unique metabolism of arsenobetaine and that arsenobetaine plays an important role in the accumulation of arsenic in these animals. [source] Reducing sea turtle by-catch in pelagic longline fisheriesFISH AND FISHERIES, Issue 1 2006Eric Gilman Abstract Reducing by-catch of sea turtles in pelagic longline fisheries, in concert with activities to reduce other anthropogenic sources of mortality, may contribute to the recovery of marine turtle populations. Here, we review research on strategies to reduce sea turtle by-catch. Due to the state of management regimes in most longline fisheries, strategies to reduce turtle interactions must not only be effective but also must be commercially viable. Because most research has been initiated only recently, many results are not yet peer-reviewed, published or readily accessible. Moreover, most experiments have small sample sizes and have been conducted over only a few seasons in a small number of fisheries; many study designs preclude drawing conclusions about the independent effect of single factors on turtle by-catch and target catch rates; and few studies consider effects on other by-catch species. In the US North Atlantic longline swordfish fishery, 4.9-cm wide circle hooks with fish bait significantly reduced sea turtle by-catch rates and the proportion of hard-shell turtles that swallowed hooks vs. being hooked in the mouth compared to 4.0-cm wide J hooks with squid bait without compromising commercial viability for some target species. But these large circle hooks might not be effective or economically viable in other longline fisheries. The effectiveness and commercial viability of a turtle avoidance strategy may be fishery-specific, depending on the size and species of turtles and target fish and other differences between fleets. Testing of turtle avoidance methods in individual fleets may therefore be necessary. It is a priority to conduct trials in longline fleets that set gear shallow, those overlapping the most threatened turtle populations and fleets overlapping high densities of turtles such as those fishing near breeding colonies. In addition to trials using large 4.9-cm wide circle hooks in place of smaller J and Japan tuna hooks, other fishing strategies are under assessment. These include: (i) using small circle hooks (, 4.6-cm narrowest width) in place of smaller J and Japan tuna hooks; (ii) setting gear below turtle-abundant depths; (iii) single hooking fish bait vs. multiple hook threading; (iv) reducing gear soak time and retrieval during daytime; and (v) avoiding by-catch hotspots through fleet communication programmes and area and seasonal closures. [source] State-dependent risk-taking by green sea turtles mediates top-down effects of tiger shark intimidation in a marine ecosystemJOURNAL OF ANIMAL ECOLOGY, Issue 5 2007MICHAEL R. HEITHAUS Summary 1A predictive framework of community and ecosystem dynamics that applies across systems has remained elusive, in part because non-consumptive predator effects are often ignored. Further, it is unclear how much individual-level detail community models must include. 2Previous studies of short-lived species suggest that state-dependent decisions add little to our understanding of community dynamics. Body condition-dependent decisions made by long-lived herbivores under risk of predation, however, might have greater community-level effects. This possibility remains largely unexplored, especially in marine environments. 3In the relatively pristine seagrass community of Shark Bay, Australia, we found that herbivorous green sea turtles (Chelonia mydas Linnaeus, 1758) threatened by tiger sharks (Galeocerdo cuvier Peron and LeSueur, 1822) select microhabitats in a condition-dependent manner. Turtles in poor body condition selected profitable, high-risk microhabitats, while turtles in good body condition, which are more abundant, selected safer, less profitable microhabitats. When predation risk was low, however, turtles in good condition moved into more profitable microhabitats. 4Condition-dependent use of space by turtles shows that tiger sharks modify the spatio-temporal pattern of turtle grazing and their impacts on ecosystem dynamics (a trait-mediated indirect interaction). Therefore, state-dependent decisions by individuals can have important implications for community dynamics in some situations. 5Our study suggests that declines in large-bodied sharks may affect ecosystems more substantially than assumed when non-lethal effects of these top predators on mesoconsumers are not considered explicitly. [source] Ultrastructural Characteristics of Blood Cells of Juvenile Loggerhead Sea Turtles (Caretta caretta)ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2007A. B. Casal Summary Ultrastructural characteristics of erythrocytes, heterophils, eosinophils, lymphocytes, monocytes and thrombocytes of the loggerhead sea turtle (Caretta caretta) were evaluated, using blood samples from 15 healthy juvenile animals. Except for the eosinophils, the rest of the white blood cells from loggerhead turtles had similar ultrastructural characteristics compared with blood cells from other sea turtle species. Eosinophils from loggerhead turtles were homogeneous in size, and no crystalline structures were observed within the granules. This paper provides an ultrastructural characterization of blood cells of loggerhead sea turtles, as a reference for future haematological studies of this species. [source] Eighteen years of saturation tagging data reveal a significant increase in nesting hawksbill sea turtles (Eretmochelys imbricata) on Long Island, AntiguaANIMAL CONSERVATION, Issue 3 2006J. I. Richardson Abstract Hawksbill sea turtle Eretmochelys imbricata nesting on Long Island, Antigua, West Indies (also known as Jumby Bay) has been monitored since 1987. Although the numbers of nesting females remained relatively constant for the first 11 survey seasons (1987,1997), inclusion of more recent data (1998,2004) in the analysis reveals a statistically significant upward trend. In particular, neophytes have shown a significant upturn in numbers, whereas the remigrant subpopulation has remained stationary. This indicates that recruitment is driving the upward trend in the total number of nesters. Predictive models based on the Poisson distribution suggest that the neophyte subpopulation will continue to grow in size by an average of 10% per annum. Model-based predictions and their limitations are discussed. The Jumby Bay Hawksbill Project, which has monitored and protected nesting hawksbills and their eggs since the project's onset, is one among several factors that may contribute to the recent increase in nesting females. [source] Effect of type of bait on pelagic longline fishery,loggerhead turtle interactions in the Gulf of Gabes (Tunisia)AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2010Khaled Echwikhi Abstract 1.Sea turtles may migrate vast distances from their feeding areas to home rookeries where they nest. During these migrations sea turtles are subject to many threats, among which are interactions with pelagic longlines. 2.This gear is used frequently in the summer period in the Gulf of Gabes targeting mainly the sandbar shark (Carcharhinus plumbeus). Hooks are baited with mackerel (Scomber scombrus) or pieces of stingray (Dasyatis pastinaca). 3.Twenty-one fishing trips (48 sets with a total of 35,950 hooks deployed) were conducted using onboard observers in the south of the Gulf of Gabes during the months of July, August and September in 2007 and 2008. Stingray and mackerel bait were used in 19 and 29 sets, respectively. 4.In total, 29 loggerhead sea turtles (Caretta caretta) were captured; the majority of them were juvenile and active. Turtles were caught at a statistically greater frequency on sets with hooks baited with mackerel than on sets with hooks baited with pieces of stingray. 5.The type of bait also affected the catch of the target species by increasing the efficiency when pieces of stingrays were used. 6.These results encourage further research into new baits to mitigate turtle catch by longline fisheries without affecting the catch of target species. Copyright © 2010 John Wiley & Sons, Ltd. [source] Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fisheryAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2010Gilberto Sales Abstract 1.Incidental catches by the pelagic longline fishery is a major global threat for loggerhead (Caretta caretta) and leatherback (Dermochelys coriacea) sea turtles. 2.The reduction of incidental capture and post-release mortality of sea turtles in the Brazilian pelagic longline fishery, operating in the south-western Atlantic Ocean, was investigated by comparing the performance of 18/0 circle hooks with 9/0 J-type (control) hooks. Hook selectivity experiments were performed between 2004 and 2008, in a total of 26 trips, 229 sets and 145 828 hooks. The experimental design included alternating control and experimental hooks along sections of the mainline. 3.An overall decrease in capture rates for loggerhead turtles of 55% and for leatherbacks of 65% were observed when using circle hooks. In addition, deep-hooking in loggerheads decreased significantly from 25% using J-hooks to 5.8% with circle hooks, potentially increasing post-release survival. 4.Circle hooks increased catch rates of most of the main target species, including tunas (bigeye Thunnus obesus and albacore T. alalunga), and sharks (blue Prionace glauca and requiem sharks of the genus Carcharinus), with no difference in the capture rates of yellowfin tuna (T. albacares), shortfin mako shark (Isurus oxyrinchus), hammerhead sharks (Sphyrna lewini and S. zygaena), and dolphinfish or mahi mahi (Coryphaena hippurus). On the other hand, a significant decrease in the capture rate of swordfish (Xiphias gladius) was detected when using circle hooks. 5.Overall, results support the effectiveness of using circle hooks for the conservation of loggerhead and leatherback sea turtles, with positive effects on capture of most target species of the south-western Atlantic longline fishery. Copyright © 2010 John Wiley & Sons, Ltd. [source] Comparing the effects of offset and non-offset circle hooks on catch rates of fish and sea turtles in a shallow longline fishery,AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 4 2010Yonat Swimmer Abstract 1.This study compared the catch rates of targeted dolphinfish or mahimahi (Coryphaena hippurus), and sea turtles and other fish bycatch in a shallow-set Costa Rican longline fishery using 14/0 circle hooks with and without a 10° offset. The effect of hook offset on hooking location and injury in captured sea turtles, specifically if the hooking was external, in the mouth, or in the esophagus was also evaluated. 2.Results were compared from six trips totalling 33 876 hooks with squid (Dosidicus gigas) used as bait. In total, mahimahi catch-per-unit-effort (CPUE, expressed as number caught per 1000 hooks) was similar between hook types (CPUE,52). 3.Olive ridley sea turtles (Lepidochelys olivacea) were caught on all 42 sets. In total, 640 olive ridley turtles were caught and released alive. There were no significant differences in the number of sea turtles caught between hooks with and without an offset (CPUE,19) nor between hook type and anatomical hooking location, suggesting similar levels of injury for turtles caught on each hook type. 4.These data suggest that a 10° offset on 14/0 circle hooks does not confer any selective advantages over hooks with no offset with respect to capture rates of mahimahi, sea turtles, sharks, or pelagic stingrays in a shallow set pelagic longline fishery. Copyright © 2010 John Wiley & Sons, Ltd. [source] Potential impacts of projected sea-level rise on sea turtle rookeriesAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 2 2010MMPB Fuentes Abstract 1.Projected sea-level rise (SLR) is expected to cause shoreline erosion, saline intrusion into the water table and inundation and flooding of beaches and coastal areas. Areas most vulnerable to these physical impacts include small, tropical low-lying islands, which are often key habitat for threatened and endemic species, such as sea turtles. 2.Successful conservation of threatened species relies upon the ability of managers to understand current threats and to quantify and mitigate future threats to these species. This study investigated how sea-level rise might affect key rookeries (nesting grounds) (n=8) for the northern Great Barrier Reef (nGBR) green turtle population, the largest green turtle population in the world. 3.3-D elevation models were developed and applied to three SLR scenarios projected by the IPCC 2007 and an additional scenario that incorporates ice melting. Results indicate that up to 38% of available nesting area across all the rookeries may be inundated as a result of SLR. 4.Flooding, as a result of higher wave run-up during storms, will increase egg mortality at these rookeries affecting the overall reproductive success of the nGBR green turtle population. Information provided will aid managers to prioritize conservation efforts and to use realistic measures to mitigate potential SLR threats to the nGBR green turtle population. Copyright © 2009 John Wiley & Sons, Ltd. [source] Relative Exposure Index: an important factor in sea turtle nesting distributionAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 2 2010J. Santana Garcon Abstract 1.The threatened status of many sea turtle populations and their vulnerability to coastal development and predicted climate change emphasize the importance of understanding the role of environmental factors in their distribution and ecological processes. The factors driving the distribution of sea turtle nesting sites at a broad spatial scale is poorly understood. 2.In light of the lack of understanding about physical factors that drive the distribution of turtle nesting, the relationship between nesting site distribution and the exposure of coastal areas to wind and wind-generated waves was analysed. To achieve this, a Relative Exposure Index (REI) was developed for an extensive area in north-eastern Australia and values of the index for nesting sites of five different sea turtle species and randomly selected non-nesting sites were compared. 3.Although there are differences between species, the results show that sea turtles nest in areas of higher REI values suggesting that wind exposure is related to the spatial distribution of sea turtle nesting sites, and it may also influence nest site selection in female turtles and/or the dispersal of hatchlings towards oceanic currents. 4.The combination of these results with further research on other driving environmental factors, like oceanic currents, has the potential to allow for the identification and prediction of future nesting sites, for which conservation and management may become essential. Copyright © 2009 John Wiley & Sons, Ltd. [source] Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 7 2009Susanna Piovano Abstract 1.A known fishing hot spot for loggerhead sea turtles (Caretta caretta) in the Mediterranean Sea is in the waters of the Strait of Sicily where interactions with fish hooks and branchlines are believed to be a major cause of mortality for sea turtles. 2.Hooks with different shapes but a similar gape width (circle hook size 16/0 vs J hook size 2) were tested in order to determine the potential effectiveness of the hook design to both reduce sea turtle capture as well as to maintain acceptable levels of target species capture rates in a shallow-set longline swordfish fishery in the Mediterranean. 3.Seven experimental fishing trips, 30,000 hooks total, were conducted on a single commercial fishing vessel (18,m in length) in the Strait of Sicily during the months of July through October over a period of three years from 2005 to 2007. Circle and J hooks were alternated along the mainline. 4.A total of 26 sea turtles were hooked, all immature-size Caretta caretta. Turtles were caught at a statistically greater frequency on J hooks than on circle hooks. The capture rate, weight, and upper jaw fork length of the target species were not significantly different between the two types of hooks employed. 5.Five sea turtles swallowed the hook and in all such cases these were J type. Circle hooks tended to be located externally and were more easily detected by fishermen, and could be removed with the correct dehooking action before returning the turtle to the sea. 6.These findings suggest that 16/0 circle hooks can effectively reduce the incidental capture of immature loggerhead sea turtles in a Mediterranean swordfish longline fishery without affecting the catch size of the target species. Copyright © 2009 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||