Variation in spatial distribution of juvenile loggerhead turtles in the eastern Atlantic and western Mediterranean Sea

[EN] Loggerhead sea turtles (Caretta caretta) originating from the Western Atlantic carry out one of the largest marine migrations, reaching the eastern Atlantic and Mediterranean Sea. It has been proposed that this transatlantic journey is simply a consequence of drifting, with the lack of a target destination and a passive dispersal with oceanic currents. This predicts that the size of the source populations and geographic distance to the feeding grounds should play important roles in defining stock composition in the eastern Atlantic and Mediterranean Sea.

Efforts to increase the participation of local communities in the conservation of the endangered loggerhead population of Cape Verde

[EN] The loggerhead population of Cape Verde is one of the most important in the world. Several islands from this archipelago capture nesting females for human consumption. This a widespread practice in the local population that can be killing more than 25% of nesting females every year. This activity is not relevant for the general economy of the country but can be important for some families.

Massive loggerhead nest predation by ghost crabs in Boavista Island (Cape Verde): implications of the absence of large predators.

[EN] The impact of nest predators on sea turtle hatching success is highly variable depending on predator abundance and also on interactions among different predators. Food web connectivity usually makes it difficult to understand predator-prey interactions and develop efficient conservation strategies. In the Cape Verde archipelago there is an important nesting area for loggerheads where ghost crabs are the only described nest predator. We have studied the impact of ghost crabs on loggerhead nests on this threatened population as well as the efficiency of several management practices to reduce this impact.

Productivity of females loggerhead from Cabo Verde Islands

[EN] The nesting colony of Caretta caretta has been recently described for the island of Boavista (Cabo Verde, 500 km off the coast of Senegal, Western Africa, FIGURE 1). Although more data is needed, it represents one of the most important populations in the North Atlantic (Brongersma, 1982; López-Jurado & Andreu, 1998; Ross, 1995). Since 1998, a tagging and management campaign was established in Boavista to study this nesting population. We present next data on reproductive biology of nesting females of Caretta caretta in Boavista during the year 2000 nesting season, in which we obtained twice as much than those tagged in 1998 and 1999 seasons; we also found some recaptures of females from preceding years, our first data on remigration interval.

The coast of Cape Verde hosts the third largest loggerhead nesting population in the world

[EN] Extensive sea turtle nesting monitoring has been conducted in several islands of the Archipelago of Cape Verde during the past years. The loggerhead turtle is the only species that nests in these islands though green and hawksbill turtle juveniles are very often found feeding around their coasts. Around 90% of loggerhead nests are deposited in the island of Boavista on approximately 50 km of white sandy beaches. This is one of the less populated islands with more inaccessible beaches, as all villages are far from the main nesting areas. Another 9% of nests are equally distributed among the islands of Sal, Maio and San Nicolau and the remaining 1% of nests are found among the other six major islands and several islets of the archipelago.

Synchrony on embryonic development of marine turtles: individual variability and environmental effects

[EN] For sea turtles, to hatch and emerge from the nest communally is essential to decrease hatchling mortality. Thus, it is very important within a nest the simultaneous fertilization and the synchronized embryonic development of all eggs. On loggerhead nesting beaches of Cape Verde we have studied the individual variability on developmental synchrony of embryos and the influence on this process of some biological, environmental and management factors. We have compared this trait within and between 34 nests naturally incubated on the beach and 34 nests relocated to a beach hatchery during the 2009 and 2010 nesting seasons.

Preliminary approach to the hatchlings sex-ratio of a population of Caretta caretta of Boavista island, Cape Verde Archipielago (Western Africa).

[EN] A nesting population of loggerhead sea turtles Caretta caretta has recently been described for Boa Vista Island, Cape Verde Archipelago (Western Africa). Since 1998, “Projecto Cabo Verde Natura 2000” has monitored three beaches during the turtle breeding season. The beaches being monitored - Calheta, Errata and Ponta Cosme - are located in the southeast part of Boa Vista Island. This work intends to give a first insight into the Boa Vista Island sea turtle population’s sex ratio using a histological approach, as sexual determination in sea turtles is known to be temperature-dependent (TSD or temperature-dependent sex determination).

Sea turtles recovered at the Wild Fauna Recovery Center in Gran Canaria (Canary Islands, Spain)

[EN] Since the beginning of the 1990's, the Wild Fauna Recovery Center in Gran Canaria Canary Islands, Spain) has received a large number of injured animals for recovery. Apart from birds and mammals, a considerable number of sea turtles representing different species are gathered each year. During the last five years (1999-2003), more than 100 turtles were sheltered annually; more than 80% successfully recovered and were released.

Synchrony on embryonic development of marine turtles: individual variability and environmental effects

[EN] For sea turtles, to hatch and emerge from the nest communally is essential to decrease hatchling mortality. Thus, it is very important within a nest the simultaneous fertilization and the synchronized embryonic development of all eggs. On loggerhead nesting beaches of Cape Verde we have studied the individual variability on developmental synchrony of embryos and the influence on this process of some biological, environmental and management factors. We have compared this trait within and between 34 nests naturally incubated on the beach and 34 nests relocated to a beach hatchery during the 2009 and 2010 nesting seasons.

Satellite tracking derived insights into migration and foraging strategies of male loggerhead turtles in the eastern Atlantic

[EN] In recent years, information about the movements and timing of migration by male sea turtles has begun to be unraveled. Here, we present the first satellite tracking of male loggerhead sea turtles (Caretta caretta) in the eastern Atlantic. Satellite linked transmitters were attached to five adult males, captured in the near shore waters off Boavista, Republic of Cape Verde. This archipelago hosts the single most important breeding site of loggerhead turtles in the eastern Atlantic.

Evaluation of male breeding population inferred from paternity analyses in the Cape Verde islands

[EN] Because of the extensive migrations of marine turtles through the ocean, many aspects of their biology have been unknown for a long time. However, much information has been recently gained from genetic studies and population monitoring of female turtles at their nesting sites. In contrast, still very little is known on the genetic diversity, population structure and dispersal patterns of the male breeding population, mainly because of the difficulty of capturing and monitoring them at sea. The aim of this study is to assess the genetic patterns of the male breeding population of the loggerhead turtle, Caretta caretta, using a non invasive approach and compare them to the female breeding population.