Green turtle (Chelonia mydas) nesting on Atol das Rocas, north-eastern Brazil, 1990–2008

Abstract

<jats:p>In this paper, information is presented on green turtle (<jats:italic>Chelonia mydas</jats:italic>) nesting on Atol das Rocas (Rocas Atoll), north-eastern Brazil. The temporal distribution of nesting events per season, annual number of nests, carapace length of nesting females, clutch size, hatching success, incubation period, internesting interval, clutch frequency, observed reproductive lifespan, and remigration period are reported. The study period included the nesting seasons from 1990 to 2008, but no regular beach monitoring was carried out in 1998 and 1999. Two sorts of methods were applied to the estimation of the annual number of nests in some seasons. Taking into account the estimated annual numbers of nests, the mean annual number of nests in the study period, excluding 1998–1999, was 335 (standard deviation = 139, range = 136–563, N = 17). An analysis of the available data indicates that the average nesting levels at the beginning of the study period (the first five seasons) and at its end (the last five seasons) were roughly the same. The mean curved carapace length of the nesting turtles decreased significantly during the study period, from 115.9 cm in 1990–1992 to 112.9 cm in 2006–2008. Atol das Rocas was established as a federal biological reserve in 1979, but regular sea turtle conservation activities actually started there in 1990. Since that year, the killing of nesting turtles has ceased, nesting activity by the turtles can proceed in an undisturbed fashion, and their clutches can incubate in a protected environment.</jats:p>

It is the time for oceanic seabirds: Tracking year‐round distribution of gadfly petrels across the Atlantic Ocean

“…Furthermore, large numbers of breeding PARM, non‐breeding PDES and PINC (year‐round) also occur between the Brazilian coast and the archipelago of Trindade and Martin Vaz (20°31′S, 29°19′W). Both areas are designated as Ecologically or Biologically Significant marine Areas (EBSAs; Convention on Biological Diversity, ) as they host several key threatened species including sea turtles (Bellini, Santos, Grossman, Marcovaldi, & Barata, ; Silva et al., ), marine mammals (Groch, Palazzo, Flores, Adler, & Fabian, ; Siciliano, Moura, Filgueiras, Rodrigues, & Leite, ), predatory fish (Hazin, Vaske, Oliveira, Macena, & Carvalho, ; Hazin et al., ), as well as other seabirds (Dias, Granadeiro, Phillips, Alonso, & Catry, ; González‐Solís et al., ; Ramos et al., ).…”

Growth rates of adult sea turtles

“…This, in turn, would lead to slower growth rates (Bjorndal et al 2000a, Balazs & Chaloupka 2004), thus decreasing both SSM and mass at sexual maturity and increasing ASM (Heppell et al 2007, Chaloupka et al 2008, potentially explaining the observed decrease in mean female size at nesting grounds in a number of recovering populations (e.g. da Silva et al 2007, Bellini et al 2013, Weber et al 2014.…”

“…This, coupled with the higher levels of predation in neritic habitats (Bolten 2003b), could help explain the decrease in mean SSM observed at nesting beaches (e.g. da Silva et al 2007, Bellini et al 2013, Weber et al 2014 and is likely to lead to a temporal variation in mean SSM. Whether ASM would follow a similar pattern seems unlikely as oceanic and neritic foragers appear to reach sexual maturity at similar ages (Hatase et al 2010).…”

“…In addition, their effectiveness decreases as population size increases unless the study area ranges widely (Witt et al 2009) to encompass flexibility in natal homing (Lee et al 2007, Ni shizawa et al 2011, Lohmann et al 2013, Brothers & Lohmann 2015 and nest site fidelity (Tucker 2010, Weber et al 2013. Although some populations are recovering (da Silva et al 2007, Bellini et al 2013, Weber et al 2014, García-cruz et al 2015, sea turtles remain conservation-dependent and require intensive management (Wallace et al 2011, Casale & Heppell 2016. Hamann et al (2010) highlight that reproductive biology and population ecology are 2 priority research categories for sea turtles, and these require methods to accurately age individuals and determine ASM.…”

Food preferences and Hg distribution in Chelonia mydas assessed by stable isotopes

“…This species often uses oceanic islands as nesting areas, and in Brazilian waters nesting females present a minimum curved carapace length (CCL) of 90 cm which could be used as a proxy for size at sexual maturation (Bellini et al, 2012;Almeida et al, 2011). Adult and neritic juvenile green turtles have a predominantly herbivorous diet (Bjorndal, 1980).…”