Características da reprodução de tartarugas marinhas (Testudines, Cheloniidae) no litoral sul da Bahia, Brasil

Abstract

Few studies have been carried out on nesting of sea turtles in the southern coast of Bahia, an area that is experiencing a fast process of tourist occupation what can increase levels of threat to these species. Thus, this study aimed to identify sea turtle species that nest in the area and to describe the main characteristics of their clutches. During four reproductive seasons, from 2004 to 2008, we identified and monitored nests found at beaches located between the municipalities of Uruçuca and Itacaré, in the southern coast of Bahia. The collected variables were: clutch size, incubation duration, hatching success and stages of embryonic mortality. We registered an average of 37 ± 6.2 nests per season, with nests of Caretta caretta and Eretmochelys imbricata being more frequent, along with sporadic nests of Chelonia mydas. Nesting season of C. caretta extends from October to January and that of E. imbricata from December to March. This temporary displacement of reproductive seasons might be related to a selective adjustment to minimize competition among species. Besides the time of nesting, the two species differed also in clutch size, but they did not differ in incubation duration and in hatching success. According to our results, we believe that areas with low concentration of nests should also be a target of conservation programs, due to their relevance to the increase of genotypic, and specially fenotypic, variation of sea turtle species, so that Brazilian populations can adapt and survive to the constant threats. Those conservation programs can be established by partnerships between non-governmental organizations and private institutions and the Brazilian government institution for the conservation of sea turtles (Centro TAMAR/ICMBio). Resumo: Poucos estudos foram realizados sobre a nidificação de tartarugas marinhas no litoral sul da Bahia, região que está passando por um processo rápido de ocupação turística que pode ameaçar ainda mais estas espécies. Por estes motivos, este estudo teve como objetivos identificar as espécies de tartarugas marinhas que desovam no local e descrever as principais características de suas ninhadas. Durante quatro temporadas reprodutivas, de 2004 a 2008, foram identificados e monitorados os ninhos encontrados nas praias localizadas entre Uruçuca e Itacaré no litoral sul da Bahia. As variáveis coletadas foram: tamanho de ninhada, duração da incubação, sucesso de eclosão e fases de mortalidade embrionária. Foi registrada uma média de 37 ± 6,2 ninhos por temporada, com maior freqüência de ninhos das espécies Caretta caretta e Eretmochelys imbricata, tendo sido registradas também desovas esporádicas de Chelonia mydas. A temporada de desova de C. caretta ocorre de outubro a janeiro e de E. imbricata de dezembro a março. Este deslocamento temporal das temporadas reprodutivas pode estar relacionado a uma adaptação para minimizar a competição interespecífica. Além da época de nidificação, as duas espécies diferiram no tamanho de suas ninhadas, mas não diferiram na duração da...

Northeast Brazil shows highest hawksbill turtle nesting density in the South Atlantic

“…Detailed density distributions (hawksbill clutches per kilometer) for each nesting season and section are available in Tables S1 & S2. Considering the total extent of the area patrolled and the number of hawksbill clutches within this area, the number of clutches per kilometer was 19.3, 15.3 and 3.3 in Paraiba (Mascarenhas et al 2004), Pernambuco (Moura et al 2012) and southern Bahia (Camilo et al 2009), respectively. In addition, although there are about 1500 hawksbill clutches each year along 214 km of nesting beaches in northern Bahia, the distribution is not homogenous, with concentrations as high as 31.6 clutches km −1 in the most dense areas (Projeto TAMAR-ICMBio unpubl.…”

“…Smaller numbers of nests also occur in the states of Sergipe ), Paraíba (Mascarenhas et al 2004), Pernambuco (Moura et al 2012) and southern Bahia (Camilo et al 2009; see Fig. 1).…”

“…However, current nesting surveys of Brazilian hawksbills rely entirely on the number of clutches per season, which alone is insufficient to determine the number of nesting females that visit a specific beach per season. To gain this understanding, more detailed information on clutch frequency and remigration intervals is required (see Mascarenhas et al 2004, Camilo et al 2009). …”

Distribuição espaço-temporal e sucesso reprodutivo de Eretmochelys imbricata nas praias do Ipojuca, Pernambuco, Brasil

“…As áreas de reprodução consideradas prioritárias para esta espécie estão localizadas no norte do estado da Bahia (MaRcovaldi et al, 1999), Sergipe e no litoral sul do Rio Grande do Norte (MaRcovaldi et al, 2011). No nordeste brasileiro, o período de nidificação ocorre entre os meses de novembro a abril (MaRcovaldi et al, 2011), tendo picos nos meses de dezembro a fevereiro na Bahia (caMillo et al, 2009) e em Sergipe (MaRcovaldi et al, 2011). Na Paraíba, a temporada reprodutiva apresenta picos em fevereiro e março (MaScaRenhaS et al, 2003), períodos caracterizados por apresentarem temperaturas elevadas, menores pluviosidade e umidade relativa (inMet, 3° Distrito).…”

Nesting and neonates of the yellow-spotted river turtle (Podocnemis unifilis, Podocnemididae) in the Araguari River basin, eastern Amazon, Brazil

“…For this procedure, eggs were handled carefully, avoiding rotation or direct exposure to the sun. Successful nests were opened during the hatching stage to check for the clutch size (number of eggs found in each nest), incubation duration, number of live and stillborn neonates, and quantification of unhatched eggs (Camillo et al 2009). …”