45 research outputs found
Biochemical indices and life traits of loggerhead turtles (Caretta caretta) from Cape Verde Islands
The loggerhead turtle (Caretta caretta) is an endangered marine reptile for whom assessing population health requires
knowledge of demographic parameters such as individual growth rate. In Cape Verde, as within several populations, adult
female loggerhead sea turtles show a size-related behavioral and trophic dichotomy. While smaller females are associated
with oceanic habitats, larger females tend to feed in neritic habitats, which is reflected in their physiological condition and in
their offspring. The ratio of RNA/DNA provides a measure of cellular protein synthesis capacity, which varies depending on
changes in environmental conditions such as temperature and food availability. The purpose of this study was to evaluate
the combined use of morphometric data and biochemical indices as predictors of the physiological condition of the females
of distinct sizes and hatchlings during their nesting season and how temperature may influence the physiological condition
on the offspring. Here we employed biochemical indices based on nucleic acid derived indices (standardized RNA/DNA
ratio-sRD, RNA concentration and DNA concentration) in skin tissue as a potential predictor of recent growth rate in nesting
females and hatchling loggerhead turtles. Our major findings were that the physiological condition of all nesting females
(sRD) decreased during the nesting season, but that females associated with neritic habitats had a higher physiological
condition than females associated with oceanic habitats. In addition, the amount of time required for a hatchling to right
itself was negatively correlated with its physiological condition (sRD) and shaded nests produced hatchlings with lower sRD.
Overall, our results showed that nucleic acid concentrations and ratios of RNA to DNA are an important tool as potential
biomarkers of recent growth in marine turtles. Hence, as biochemical indices of instantaneous growth are likely
temperature-, size- and age-dependent, the utility and validation of these indices on marine turtles stocks deserves further
study.The authors thank the Cape Verde Ministry of Environment (General Direction for the Environment), INDP (National Fisheries Institution), the Canary
Islands Government (D.G. Africa and D.G. Research and Universities), ICCM (Canarian Institution for Marine Sciences), the Andalusian Government (Andalusian
Environmental Office) and AEGINA PROJECT (INTERREG IIIB) for funding and hosting them during this study. The authors also thank the European Regional
Development Fund (ERDF) through the COMPETE - Operational Competitiveness Programme, and national funds through FCT - PEst-C/MAR/LA0015/2011 for
supporting the biochemical analysis
Prevalence and clinical features of celiac disease in patients with hepatitis B virus infection in Southern Brazil
Dispersal and dive patterns during the post-nesting migration of olive ridley turtles from French Guiana
Do heavy metals represent a risk fo developing leatherback embryos? A monitoring in French Guyana
Numerical simulation of buffeting over airfoil using dual time stepping method
Communication to : ECCOMAS 2000, Barcelona (Spain), September 11-14, 2000SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : 22419, issue : a.2000 n.231 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Recent Demographic History and Present Fine-Scale Structure in the Northwest Atlantic Leatherback (Dermochelys coriacea) Turtle Population
The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic diversity and species history