Shark scavenging and predation on sea turtles in northeastern Brazil

2012 ◽  
Vol 33 (3-4) ◽  
pp. 495-502 ◽  
Author(s):  
Hugo Bornatowski ◽  
Michael R. Heithaus ◽  
Clenia M.P. Batista ◽  
Rita Mascarenhas

Large sharks have the potential to help structure ecosystem dynamics through top-down impacts on their prey, including sea turtles. Studies of interactions between large sharks and sea turtles, however, are practically nonexistent along the Brazilian coast. Between September 2002 and May 2011 we examined 655 sea turtles – including green turtles Chelonia mydas (n = 607), olive ridleys Lepidochelys olivacea (n = 10), hawksbills Eretmochelys imbricata (n = 33), and loggerheads Caretta caretta (n = 5) – that stranded on Paraíba coast, northeastern Brazil. A total of 63 green turtles (10.4%), two olive ridleys (20.0%) and one hawksbill (3.0%) had shark-inflicted bites. Most bites could not be definitively attributed to scavenging or attacks on living turtles, but the presence of healed shark bites and freshly bleeding bites suggests that some attacks occurred pre-mortem. Bite characteristics suggest that tiger sharks Galeocerdo cuvier were responsible for most bites that could be identified to a particular species. Within green turtles, the only species with sufficient sample size, the probability of carcasses having been bitten increased with carapace length but did not vary across seasons and years. However, there was spatial variation in the probability of a carcass having been bitten by sharks. Our estimates of the minimum proportion of turtles attacked while alive (∼4%) and bitten overall are similar to other areas where shark-turtle interactions have been studied. Turtles likely are an important food for tiger sharks in northeastern Brazil, but further studies are needed to determine the relative frequencies of scavenging and predation.

2015 ◽  
Vol 105 (3) ◽  
pp. 265-270 ◽  
Author(s):  
Camila Poli ◽  
Daniel Oliveira Mesquita ◽  
Cinthia Saska ◽  
Rita Mascarenhas

ABSTRACT Currently, plastics are recognized as a major pollutant of the marine environment, representing a serious threat to ocean wildlife. Here, we examined the occurrence and effects of plastic ingestion by sea turtles found stranded along the coast of Paraíba State, Brazil from August 2009 to July 2010. Ninety-eight digestive tracts were examined, with plastic found in 20 (20.4%). Sixty five percent (n = 13) of turtles with plastic in the digestive tract were green turtles (Chelonia mydas), 25% (n = 5) were hawksbills (Eretmochelys imbricata), and 10% (n = 2) were olive ridley (Lepidochelys olivacea). More plastic was found in the intestine (85%) than in other parts of the gastrointestinal tract. We observed complete blockage of the gastrointestinal tract due to the presence of plastic in 13 of the 20 turtles that had ingested plastic. No correlation was found between the curved carapace length (CCL) and the number or mass of the plastic ingested items. Significant differences were found between the intake of hard and soft plastic and the ingestion of white/transparent and colored plastic, with soft and white/transparent plastics being more commonly ingested. This study reveals the serious problem of plastic pollution to sea turtles at the area.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Sibelle Torres Vilaça ◽  
Fabricio Rodrigues dos Santos

We report here a dataset comprising nine nuclear markers for the Brazilian population of Cheloniidae turtles: hawksbills (Eretmochelys imbricata), loggerheads (Caretta caretta), olive ridleys (Lepidochelys olivacea), and green turtles (Chelonia mydas). Because hybridization is a common phenomenon between the four Cheloniidae species nesting on the Brazilian coast, we also report molecular markers for the hybrids E. imbricata × C. caretta, C. caretta × L. olivacea, and E. imbricata × L. olivacea and for one hybrid E. imbricata × C. mydas and one between three species C. mydas × E. imbricata × C. caretta. The data was used in previous studies concerning (1) the description of frequent hybrids C. caretta × E. imbricata in Brazil, (2) the report of introgression in some of these hybrids, and (3) population genetics. As a next step for the study of these hybrids and their evolution, genome-wide studies will be performed in the Brazilian population of E. imbricata, C. caretta, and their hybrids.


2021 ◽  
Vol 58 (4) ◽  
pp. 408-414
Author(s):  
H. Jerdy ◽  
R. B. Ferioli ◽  
H. Gallo Neto ◽  
M. Zíllio ◽  
A. Monteiro ◽  
...  

Summary The present study reports the first occurrence of Plesiochorus cymbiformis (Digenea: Gorgoderidae), in two Olive Ridley Sea turtles Lepidochelys olivacea (Testudines: Chelonidae), from the states of São Paulo and Sergipe in Brazilian coast. Concerning the Neotropical region, P. cymbiformis has been previously reported in green sea turtles (Chelonia mydas) from Panama and Brazil, in loggerhead sea turtles (Caretta caretta) from Brazil, in hawksbill sea turtles (Eretmochelys imbricata) from Puerto Rico, and in Olive Ridley Sea turtles only in Costa Rica. Lesions resulting from the presence of parasites in the hosts’ urinary bladders are also presented. This is the second report on endoparasites in Olive Ridley sea turtles from Brazil.


2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Cristiano Leite Parente ◽  
Juliana Doyle Lontra ◽  
Maria Elisabeth de Araújo

There are seven species of sea turtles around the world. Among these, five visit the northeast coast of Brazil to reproduce and feed. These sea turtles are impacted by human activity and need conservation measures. The seismic survey is one of these activities due to its high intensity and low frequency sound emissions in the marine environment. Records of sea turtles during seismic surveys in shallow waters of the northeast of Brazil between 2002 and 2003 are presented in this study with some discussion about the effectiveness of the monitoring procedures. Three species of sea turtle were recorded within the seismic survey areas. The Chelonia mydas species was the most commonly sighted turtle. There was only one record of Caretta caretta and Lepidochelys olivacea. The presence of sea turtles in Sergipe state was linked to the reproductive period while this pattern was not observed in Ceará state. The absence of information about distribution and abundance of sea turtles in the surveyed areas previous to and after the seismic surveys, as well as numerous incomplete data make it hard to identify the effect of seismic surveys on those factors and also sea turtle behaviors.


1985 ◽  
Vol 12 (3) ◽  
pp. 523 ◽  
Author(s):  
CJ Limpus ◽  
PC Reed

Cyclone Kathy on 23 March 1984 stranded many green turtles, Chelonia mydas, on the coast adjacent to the Sir Edward Pellew Is. It is estimated that over 1000 were thrown up by the storm surge and that over 500 were left stranded by the receding waters, including migrants from the Raine I. rookery. These turtles, which were predominately large females, had been feeding close inshore on seagrass. Of the mature females sampled, 62% were preparing to breed in the next breeding season but none had bred in the previous season. The flatback turtle, Chelonia depressa, the principal species breeding on the Sir Edward Pellew Is, was not involved in the stranding. Hawksbill turtles, Eretmochelys imbricata, and olive ridley turtles, Lepidochelys olivacea, which occur in the deeper offshore waters were also not stranded. Some of the rescued turtles were subsequently recaptured nesting at Raine I.


2021 ◽  
Vol 16 (4) ◽  
pp. 521-538
Author(s):  
Raísa da Silva Costa Rêgo ◽  
Eric Azevedo Cazetta ◽  
Caio Henrique Gonçalves Cutrim ◽  
Amanda Soares Miranda ◽  
Ana Paula Albano Araújo ◽  
...  

The south-western region of the Atlantic Ocean has feeding and nesting areas for the five species of sea turtles registered in Brazil, which are in different degrees of extinction threat, mainly due to anthropogenic factors. Fishing and the ingestion of solid waste, were identified as causing stranding and the mortality of sea turtles. In this work, data from the monitoring of beaches in the Municipalities of Macaé and Rio das Ostras, important oil zone in Brazil, in the north-central region of the State of Rio de Janeiro, were used in order to analyse the effects of seasonality on the sea turtle stranding. The monitoring was carried out daily from September 2017 to June 2019, in a study area covering 23.8 km long beach. Stranding data were obtained from active (n = 126) and passive (n = 66) monitoring of beaches and included the records of Chelonia mydas (n = 151), Caretta caretta (n = 23), Lepidochelys olivacea (n = 14), Dermochelys coriacea (n = 2) and Eretmochelys imbricata (n = 1). The largest stranding record occurred in the summer (n = 61) and spring (n = 60), a period compatible with the reproductive season of the species. The results obtained in this study emphasise the importance of the analysis of strandings of sea turtles, which provide relevant data on the biology of the group, the intra and interspecific dynamics and the state of conservation of these animals.


2016 ◽  
Vol 3 (1) ◽  
pp. 20-23
Author(s):  
Sergio Escobar-Lasso ◽  
Luis Fonseca ◽  
Wilbert N. Villachica ◽  
Hansel Herrera ◽  
Roldán A. Valverde ◽  
...  

Jaguars have been recorded preying on adult female sea turtles on their nesting beaches in Costa Rica, Guyana, Mexico and Suriname (Fretey 1977, Autar 1994, Cuevas et al. 2014, Guildera et al. 2015). Jaguars prey on Green (Chelonia mydas), Olive Ridley (Lepidochelys olivacea), Hawksbill (Eretmochelys imbricata), and Leatherback (Dermochelys coriacea) sea turtles (see Fretey 1977, Autar 1994, Carrillo et al. 1994, Chinchilla 1997, Tröeng 2000, Heithaus et al. 2008, Veríssimo et al. 2012, Arroyo-Arce et al. 2014, Cuevas et al. 2014, Arroyo-Arce & Salom-Pérez 2015, Guildera et al. 2015). The capture effort and risk of injury associated with the predation of nesting sea turtles is expected to be lower relative to other prey species in the jaguar’s diet (Cavalcanti & Gese 2010). Additionally, they can be key resources when other pr ey availability is low (Veríssimo et al. 2012).


1998 ◽  
Vol 49 (5) ◽  
pp. 409 ◽  
Author(s):  
A. R. Pople ◽  
A. N. Gordon ◽  
J. Ng

The concentrations of some or all of arsenic (As), cadmium (Cd), mercury (Hg), selenium (Se) and zinc (Zn) were determined in the livers and kidneys of 50 stranded sea turtles (38 Chelonia mydas, eight Caretta caretta, three Eretmochelys imbricata, one Lepidochelys olivacea) from the Moreton Bay region of south-eastern Queensland, Australia. Concentrations of Cd, Se and Zn in the kidney tended to decrease with age, whereas concentrations of Zn in the liver tended to increase. Concentrations of Cd in all sea turtle species (1.7–75.9 µg g-1 wet weight) were amongst the highest recorded for marine vertebrates globally. Although there was no obvious association between metal concentrations and particular diseases in C. mydas, the high concentrations of Cd found in edible turtle tissues may pose a threat to the health of indigenous people whose diet includes C. mydas.


2016 ◽  
Vol 53 (3) ◽  
pp. 211-223 ◽  
Author(s):  
M. R. Werneck ◽  
R. J. Da Silva

SummaryThis paper presents a list of parasites described in sea turtles from the Neotropical region. Through the review of literature the occurrence of 79 taxa of helminthes parasites were observed, mostly consisting of the Phylum Platyhelminthes with 76 species distributed in 14 families and 2 families of the Phylum Nematoda within 3 species. Regarding the parasite records, the most studied host was the green turtle (Chelonia mydas) followed by the hawksbill turtle (Eretmochelys imbricata), olive ridley turtle (Lepidochelys olivacea), loggerhead turtle (Caretta caretta) and leatherback turtle (Dermochelys coriacea). Overall helminths were reported in 12 countries and in the Caribbean Sea region. This checklist is the largest compilation of data on helminths found in sea turtles in the Neotropical region.


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