Sea Turtle Bycatch in the Large-Mesh Gillnet Flounder Fishery in Carteret County, North Carolina, USA, June-November 2009

2016 ◽  
Vol 132 (1-2) ◽  
pp. 10-24 ◽  
Author(s):  
Barbie L. Byrd ◽  
Lisa R. Goshe ◽  
Trip Kolkmeyer ◽  
Aleta A. Hohn
Keyword(s):  
North Carolina ◽  
Endangered Species Act ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Mitigation Measures ◽  
String Length ◽  
Lepidochelys Kempii ◽  
Turtle Species ◽  
Spatio Temporal ◽  
June July

Abstract Sea turtle bycatch has been documented in the large-mesh gillnet fishery that targets flounder in estuarine waters of North Carolina (NC). However, only portions of the fishery operated under Endangered Species Act Incidental Take Permits and had regular observer coverage to determine the occurrence and extent of sea turtle bycatch. From June through November 2009, an Alternative Platform Observer Program (APOP) was initiated in southeastern Carteret County, NC, to document turtle entanglements. Observers covered 1.6% of the total number of large-mesh gillnet trips reported (1.1% of landings) and documented turtle bycatch (n = 22) on 36% of the observed trips (12 of 33). Most turtles were recovered alive (n = 15), and all interactions occurred in June, July, and August. Bycaught sea turtle species included 12 greens (Chelonia mydas), 5 Kemp’s ridleys (Lepidochelys kempii), and 5 loggerheads (Caretta caretta). Hauls with bycaught turtles in June had a significantly greater mean string length than those without bycatch (P = 0.02), but despite the institution of regulations limiting string length, no difference was found in mean string length overall before (June) and after (July-November) regulations went into effect. Documented turtle bycatch in this area supports the need for observer coverage across the entire spatio-temporal scope of the fishery at levels necessary for robust bycatch estimates. Representative observer data across longer time series can inform managers where and when bycatch risks are greatest and help in developing mitigation measures that decrease bycatch risk while reducing negative economic impacts on the fishers.

scholarly journals Using Random Forest Algorithm to Model Cold Stunning Events in Sea Turtles in North Carolina

2020 ◽  
pp. 0000-0000
Author(s):  
Jennifer N Niemuth ◽  
Casey C Ransom ◽  
Sarah A Finn ◽  
Matthew H Godfrey ◽  
Stacy A.C. Nelson ◽  
...  
Keyword(s):  
North Carolina ◽  
Random Forest ◽  
Air Temperature ◽  
Sea Turtles ◽  
Meteorological Data ◽  
Warning System ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Turtle Species ◽  
Change In Mean

Sea turtle strandings due to cold stunning are seen when turtles are exposed to ocean temperatures that acutely and persistently drop below approximately 12 °C. In North Carolina, this syndrome affects imperiled loggerhead Caretta caretta, green Chelonia mydas, and Kemp's ridley Lepidochelys kempii sea turtle species. Based on oceanic and meteorological patterns of cold stunning in sea turtles, we hypothesized that we could predict the daily size of cold stunning events in North Carolina using random forest models. We used cold stunning data from the North Carolina Sea Turtle Stranding and Salvage Network from 2010-2015 and oceanic and meteorological data from the National Data Buoy Center from 2009-2015 to create a random forest model that explained 99% of the variance. We explored additional models using the 10 and 20 most important variables or only oceanic and meteorological variables. These models explained similar percentages of variance. The variables most frequently found to be important were related to air temperature, atmospheric pressure, wind direction, and wind speed. Surprisingly, variables associated with water temperature, which is critical from a biological perspective, were not among the most important variables identified. We also included variables for the mean change in these metrics daily from 4 days prior to the day of stranding. These variables were among the most important in several of our models, especially the change in mean air temperature from 4 days prior to stranding to the day of stranding. The importance of specific variables from our RF models can be used to guide the selection of future model predictors to estimate daily size of cold stunning events. We plan to apply the results of this study to a predictive model that can serve as a warning system and to a downscaled climate projection to determine the potential impact of climate change on cold stunning event size in the future.

scholarly journals Incidental capture of sea turtles by industrial bottom trawl fishery in the Tropical South-western Atlantic

2017 ◽  
Vol 98 (6) ◽  
pp. 1525-1531 ◽  
Author(s):  
Suzana Machado Guimarães ◽  
Davi Castro Tavares ◽  
Cassiano Monteiro-Neto
Keyword(s):  
Sea Turtles ◽  
Action Plan ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Bottom Trawl ◽  
Conservation Strategies ◽  
Future Research ◽  
Olive Ridley ◽  
Western Atlantic ◽  
Turtle Species

The five sea turtle species occurring in Brazilian waters are susceptible to threats, including incidental catches by fisheries. Studies on incidental captures in fishing gears are the main focus of several conservation actions due to high sea turtle fishery mortality worldwide. This study provides the first evaluation of incidental sea turtle catches by industrial bottom trawl fisheries operating in Brazilian waters. Four twin-trawler vessels were monitored between July 2010 and December 2011 by captains who voluntarily completed logbooks. Forty-four turtles were captured during the 1996 tows (8313 fishing hours), resulting in a catch of 5.3 ± 0.8 turtles per 1000 h per unit effort. Captured species included the loggerhead turtle (Caretta caretta, 22 individuals), olive ridley turtles (Lepidochelys olivacea, 21 individuals) and one green turtle (Chelonia mydas). Water depth was the only variable that significantly affected sea turtle captures according to Generalized Linear Models. The capture rates reported in this study ranked sixth in relation to other published studies of similar fisheries occurring worldwide. Considering the importance of this region for sea turtles, the increasing evidence of sea turtle mortality and the goals of the National Action Plan for Conservation of Sea Turtles in Brazil, it is essential to identify the main threats towards these animals and propose mitigating solutions to reduce sea turtle mortality induced by fishing activities. This study provides results that may guide future research and goals in meeting sea turtle conservation strategies.

Sea Turtle Navigation and the Detection of Geomagnetic Field Features

1998 ◽  
Vol 51 (1) ◽  
pp. 10-22 ◽  
Author(s):  
Kenneth J. Lohmann ◽  
Catherine M. F. Lohmann
Keyword(s):  
Chelonia Mydas ◽  
Sea Turtle ◽  
Ocean Basin ◽  
Open Ocean ◽  
Continuous Series ◽  
Turtle Species ◽  
Green Turtles ◽  
Open Sea ◽  
Circular Current ◽  
Distant Target

The lives of sea turtles consist of a continuous series of migrations. As hatchlings, the turtles swim from their natal beaches into the open sea, often taking refuge in circular current systems (gyres) that serve as moving, open-ocean nursery grounds. The juveniles of many populations subsequently take up residence in coastal feeding areas that are located hundreds or thousands of kilometres from the beaches on which the turtles hatched; some juveniles also migrate between summer and winter habitats. As adults, turtles periodically leave their feeding grounds and migrate to breeding and nesting regions, after which many return to their own specific feeding sites. The itinerant lifestyle characteristic of most sea turtle species is thus inextricably linked to an ability to orient and navigate accurately across large expanses of seemingly featureless ocean.In some sea turtle populations, migratory performance reaches extremes. The total distances certain green turtles (Chelonia mydas) and loggerheads (Caretta caretta) traverse over the span of their lifetimes exceed tens of thousands of kilometres, several times the diameter of the turtle's home ocean basin. Adult migrations between feeding and nesting habitats can require continuous swimming for periods of several weeks. In addition, the paths of migrating turtles often lead almost straight across the open ocean and directly to the destination, leaving little doubt that turtles can navigate to distant target sites with remarkable efficiency.

scholarly journals Quantifying Illegal Extraction of Sea Turtles in Costa Rica

2021 ◽  
Vol 2 ◽  
Author(s):  
Helen Pheasey ◽  
George Glen ◽  
Nicole L. Allison ◽  
Luis G. Fonseca ◽  
Didiher Chacón ◽  
...  
Keyword(s):  
Costa Rica ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Wildlife Trade ◽  
Caribbean Coast ◽  
Turtle Species ◽  
Illegal Wildlife Trade ◽  
The Caribbean ◽  
The Impact

Estimates of illegal wildlife trade vary significantly and are often based on incomplete datasets, inferences from CITES permits or customs seizures. As a result, annual global estimates of illegal wildlife trade can vary by several billions of US dollars. Translating these figures into species extraction rates is equally challenging, and estimating illegal take accurately is not achievable for many species. Due to their nesting strategies that allow for census data collection, sea turtles offer an exception. On the Caribbean coast of Costa Rica, three sea turtle species (leatherback, Dermochelys coriacea; green, Chelonia mydas; and hawksbill, Eretmochelys imbricata) are exploited by poachers. Despite the consumption of turtle eggs and meat being illegal, they are consumed as a cultural food source and seasonal treat. Conservation programmes monitor nesting beaches, collect abundance data and record poaching events. Despite the availability of robust long-term datasets, quantifying the rate of poaching has yet to be undertaken. Using data from the globally important nesting beach, Tortuguero, as well as beaches Playa Norte and Pacuare on the Caribbean coast of Costa Rica, we modelled the spatial and temporal distribution of poaching of the three sea turtle species. Here, we present data from 2006 to 2019 on a stretch of coastline covering c.37 km. We identified poaching hotspots that correlated with populated areas. While the poaching hotspots persisted over time, we found poaching is declining at each of our sites. However, we urge caution when interpreting this result as the impact of poaching varies between species. Given their low abundance on these beaches, the poaching pressure on leatherback and hawksbill turtles is far greater than the impact on the abundant green turtles. We attribute the decline in poaching to supply-side conservation interventions in place at these beaches. Finally, we highlight the value of data sharing and collaborations between conservation NGOs.

Comparative Cytogenetics of Four Sea Turtle Species (Cheloniidae): G-Banding Pattern and in situ Localization of Repetitive DNA Units

2020 ◽  
Vol 160 (9) ◽  
pp. 531-538
Author(s):  
Caroline R.D. Machado ◽  
Larissa Glugoski ◽  
Camila Domit ◽  
Marcela B. Pucci ◽  
Daphne W. Goldberg ◽  
...  
Keyword(s):  
Ribosomal Dna ◽  
Sea Turtles ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Marine Biodiversity ◽  
Comparative Cytogenetics ◽  
Turtle Species ◽  
Lepidochelys Olivacea ◽  
Karyotypic Formula

Sea turtles are considered flagship species for marine biodiversity conservation and are considered to be at varying risk of extinction globally. Cases of hybridism have been reported in sea turtles, but chromosomal analyses are limited to classical karyotype descriptions and a few molecular cytogenetic studies. In order to compare karyotypes and understand evolutive mechanisms related to chromosome dif­ferentiation in this group, <i>Chelonia mydas</i>, <i>Caretta caretta</i>, <i>Eretmochelys imbricata</i>, and <i>Lepidochelys olivacea</i> were cytogenetically characterized in the present study. When the obtained cytogenetic data were compared with the putative ancestral Cryptodira karyotype, the studied species showed the same diploid number (2n) of 56 chromosomes, with some variations in chromosomal morphology (karyotypic formula) and minor changes in longitudinal band locations. In situ localization using a 18S ribosomal DNA probe indicated a homeologous microchromosome pair bearing a 45S ribosomal DNA locus and size heteromorphism in all 4 species. Interstitial telomeric sites were identified in a microchromosome pair in <i>C. mydas</i> and <i>C. caretta</i>. The data showed that interspecific variations occurred in chromosomal sets among the Cheloniidae species, in addition to other Cryptodira karyotypes. These variations generated lineage-specific karyotypic diversification in sea turtles, which will have considerable implications for hybrid recognition and for the study, the biology, ecology, and evolutionary history of regional and global populations. Furthermore, we demonstrated that some chromosome rearrangements occurred in sea turtle species, which is in conflict with the hypothesis of conserved karyotypes in this group.

scholarly journals Emergence of a Novel Pathogenic Poxvirus Infection in the Endangered Green Sea Turtle (Chelonia mydas) Highlights a Key Threatening Process

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 219
Author(s):  
Subir Sarker ◽  
Christabel Hannon ◽  
Ajani Athukorala ◽  
Helle Bielefeldt-Ohmann
Keyword(s):  
Sequence Data ◽  
Sequence Similarity ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Marine Turtle ◽  
In Vivo Studies ◽  
Avian Host ◽  
The Novel ◽  
Green Sea Turtle ◽  
Turtle Species

Emerging viral disease is a significant concern, with potential consequences for human, animal and environmental health. Over the past several decades, multiple novel viruses have been found in wildlife species, including reptiles, and often pose a major threat to vulnerable species. However, whilst a large number of viruses have been described in turtles, information on poxvirus in cheloniids remains scarce, with no molecular sequence data available to date. This study characterizes, for the first time, a novel poxvirus, here tentatively designated cheloniid poxvirus 1 (ChePV-1). The affected cutaneous tissue, recovered from a green sea turtle (Chelonia mydas) captured off the Central Queensland coast of Australia, underwent histological examination, transmission electron microscopy (TEM), DNA extraction and genomic sequencing. The novel ChePV-1 was shown to be significantly divergent from other known poxviruses and showed the highest sequence similarity (89.3%) to avipoxviruses (shearwater poxvirus 2 (SWPV2)). This suggests the novel ChePV-1 may have originated from a common ancestor that diverged from an avipoxvirus-like progenitor. The genome contained three predicted unique genes and a further 15 genes being truncated/fragmented compared to SWPV2. This is the first comprehensive study that demonstrates evidence of poxvirus infection in a marine turtle species, as well as a rare example of an avipoxvirus crossing the avian-host barrier. This finding warrants further investigations into poxvirus infections between species in close physical proximity, as well as in vitro and in vivo studies of pathogenesis and disease.

scholarly journals DISTRIBUCIÓN DE PLAYAS DE ANIDACIÓN Y ÁREAS DE ALIMENTACIÓN DE TO RTUGAS MARINAS Y SUS AMENAZAS EN EL CARIBE COLOMBIANO

2016 ◽  
Vol 33 ◽  
Author(s):  
Claudia Ceballos Fonseca
Keyword(s):  
Chelonia Mydas ◽  
Sea Turtle ◽  
Local Communities ◽  
Regional Level ◽  
Turtle Species ◽  
Green Turtles ◽  
Direct Observations ◽  
Counting Data ◽  
The Caribbean ◽  
San Andres

Between June and October 2002, six field assistants covered the Colombian Caribbean seashore gathering morphological, biotic and socio-cultural information, by direct observations and interviews with the local communities and authorities. From 1,650 km of Caribbean seashore, 181 beaches (730 km), are visited by one or all sea turtle species to nest or feed in surrounding grounds. Species distribution varied along the different regions of the Colombian Caribbean; however, there was a tendency of some species for specific ecosystems. Green turtles (Chelonia mydas) were most often found in the central Guajira, where sea grasses are most abundant, and hawksbills (E retmochelys imbricata) were most abundant on the coral reefs areas around San Bernardo, Rosario, Fuerte and Tortuguilla islands and the San Andrés cays. Though there was no sea turtle marking or individual counting, data was good enough to establish relative abundance categories as rare, common, and abundant. These categories, along with the also categorized identified threats, allowed me to make regional level recommendations for the conservation of sea turtles in the Caribbean coast of Colombia.

scholarly journals Evolutionary Comparisons of Chelonid Alphaherpesvirus 5 (ChHV5) Genomes from Fibropapillomatosis-Afflicted Green (Chelonia mydas), Olive Ridley (Lepidochelys olivacea) and Kemp’s Ridley (Lepidochelys kempii) Sea Turtles

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2489
Author(s):  
Liam Whitmore ◽  
Kelsey Yetsko ◽  
Jessica A. Farrell ◽  
Annie Page-Karjian ◽  
Whitney Daniel ◽  
...  
Keyword(s):  
Gene Evolution ◽  
Disease Incidence ◽  
Keystone Species ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Neoplastic Disease ◽  
Nucleotide Polymorphisms ◽  
Oncogenic Virus ◽  
Olive Ridley ◽  
Turtle Species

The spreading global sea turtle fibropapillomatosis (FP) epizootic is threatening some of Earth’s ancient reptiles, adding to the plethora of threats faced by these keystone species. Understanding this neoplastic disease and its likely aetiological pathogen, chelonid alphaherpesvirus 5 (ChHV5), is crucial to understand how the disease impacts sea turtle populations and species and the future trajectory of disease incidence. We generated 20 ChHV5 genomes, from three sea turtle species, to better understand the viral variant diversity and gene evolution of this oncogenic virus. We revealed previously underappreciated genetic diversity within this virus (with an average of 2035 single nucleotide polymorphisms (SNPs), 1.54% of the ChHV5 genome) and identified genes under the strongest evolutionary pressure. Furthermore, we investigated the phylogeny of ChHV5 at both genome and gene level, confirming the propensity of the virus to be interspecific, with related variants able to infect multiple sea turtle species. Finally, we revealed unexpected intra-host diversity, with up to 0.15% of the viral genome varying between ChHV5 genomes isolated from different tumours concurrently arising within the same individual. These findings offer important insights into ChHV5 biology and provide genomic resources for this oncogenic virus.

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