Mostrando recursos 141 - 160 de 1.741

  1. Population structure and conservation implications for the loggerhead sea turtle of the Cape Verde Islands

    Monzón Argüello, Catalina; Rico, Ciro; Naro Maciel, Eugenia; Varo Cruz, Nuria; López, Pedro; Marco, Adolfo; López-Jurado, Luis Felipe

    [EN] The Cape Verde Islands harbour the second largest nesting aggregation of the globally endangered loggerhead sea turtle in the Atlantic. To characterize the unknown genetic structure, connectivity, and demographic history of this population, we sequenced a segment of the mitochondrial (mt) DNA control region (380 bp, n = 186) and genotyped 12 microsatellite loci (n = 128) in females nesting at three islands of Cape Verde. No genetic differentiation in either haplotype or allele frequencies was found among the islands (mtDNA FST = 0. 001, P > 0. 02; nDNA FST = 0. 001, P > 0. 126). However,...

  2. Genetic characterization of eastern Atlantic hawksbill turtles at a foraging group indicates major undiscovered nesting populations in the region

    Monzón Argüello, Catalina; Rico, Ciro; Marco, Adolfo; López, Pedro; López-Jurado, Luis Felipe

    [EN] Despite the considerable population genetic and connectivity research on the hawksbill sea turtle (Eretmochelys imbricata) and the species being critically endangered, the eastern Atlantic remains understudied. We present the first analysis of mitochondrial DNA (mtDNA) sequences (n = 28) of hawksbill juveniles in a foraging aggregation at the Cape Verde Islands. Our results showed three haplotypes non-reported in any nesting population to date, with one of them accounting for 68% of the samples. These three haplotypes were closely related to each other but highly divergent from all known Caribbean and Western Atlantic haplotypes.

  3. Fusarium solani is responsible for mass mortalities in nests of loggerhead sea turtle, Caretta caretta, in Boavista, Cape Verde

    Sarmiento-Ramírez, Jullie M.; Abella Pérez, Elena; Martín, María P.; Tellería, María T; López-Jurado, Luis Felipe; Marco, Adolfo; Diéguez-Uribeondo, Javier

    [EN] The fungus Fusarium solani (Mart.) Saccardo (1881) was found to be the cause of infections in the eggs of the sea turtle species Caretta caretta in Boavista Island, Cape Verde. Egg shells with early and severe symptoms of infection, as well as diseased embryos were sampled from infected nests. Twenty-five isolates with similar morphological characteristics were obtained. Their ITS rRNA gene sequences were similar to the GenBank sequences corresponding to F. solani and their maximum identity ranged from 95% to 100%.

  4. Evidence from genetic and Lagrangian drifter data for transatlantic transport of small juvenile green turtles

    Monzón Argüello, Catalina; López-Jurado, Luis Felipe; Rico, Ciro; Marco, Adolfo; López, Pedro; Hays, Graeme; Lee, Patricia

    [EN] Aim: A key life-history component for many animals is the need for movement between different geographical locations at particular times. Green turtle (Chelonia mydas) hatchlings disperse from their natal location to spend an early pelagic stage in the ocean, followed by a neritic stage where small juveniles settle in coastal areas. In this study, we combined genetic and Lagrangian drifter data to investigate the connectivity between natal and foraging locations. In particular, we focus on the evidence for transatlantic transport.

  5. Abundance and exploitation of loggerhead turtles nesting in Boa Vista Island, Cape Verde: The only substantial rookery in the eastern Atlantic.

    Marco, Adolfo; Abella Pérez, Elena; Liria-Loza, Ana; Martins, Samir; López, Óscar; Jiménez Bordón, Saray; Medina, M; Oujo-Alamo, Carolina; Gaona, Pilar; Godley, B. J; López-Jurado, Luis Felipe

    [EN] The main nesting area for loggerhead turtles in the eastern Atlantic is in the Cape Verde Islands, largely restricted to the island of Boa Vista. Extensive monitoring demonstrated a globally significant population for the species despite a sustained high level of anthropogenic take of nesting females for local consumption. Through an extensive stratified monitoring program across the island in the seasons 2007-2009, we estimated a total of 13955, 12028 and 19950 clutches in the 3 years, respectively. These values indicate that the mean number of nesting females averaged 3700. Considering that a female breed, on average, every 2.4 years,...

  6. Primeras evidencias de la supervivencia del escinco gigante de Cabo Verde, Macroscincus coctei (Duméril & Bibron, 1839)

    Mateo, José Antonio; López-Jurado, Luis Felipe; García Márquez, Marcos

    [ES] La controvertida historia del escinco gigante de Cabo Verde, Macroscincus coctei, se ha convertido con el tiempo en uno de los ejemplos clásicos que sirven para ilustrar modelos de extinción en islas (Pregill, 1986). Sin embargo, son muchos los que siguen preguntándose si en esta especie el proceso ha llegado a su fin, o si por el contrario aún cabe la posibilidad de encontrar pequeñas poblaciones que permitan recuperarla (Schleich, 1979; Andreone & Gavetti, 1998; Carranza et al., 2001).

  7. Influence of loggerhead egg agregation on survival: why does single eggs buried into natural sand dye in few days?

    Domínguez, Jara; Marco, Adolfo; García Cerdá, Rosa María; Abella Pérez, Elena; Vieira, Sara; López-Jurado, Luis Felipe

    [EN] The incubation is an essential life period for oviparous species that very often experiences a high mortality. In some reptile species the number of eggs that develop together in the incubation chamber affects survival and hatchling phenotype. Sea turtle eggs develop in underground locations on sandy beaches in large masses that usually have more than 80 eggs. Natural egg mortality seems to vary among species and for the sensitive leatherbacks, external eggs seems to survive better than internal ones within the nest.

  8. Genetic characterization of hawksbill juveniles foraging at Cape Verde islands indicates major undiscovered nesting populations in the region

    Monzón Argüello, Catalina; Rico, Ciro; Marco, Adolfo; López, Pedro; López-Jurado, Luis Felipe

    [EN] The hawksbill sea turtle (Eretmochelys imbricata) is a circumglobal tropical species listed as Critically Endangered by the IUCN. While it is known that at least one stock occurs around the rookeries of São Tome and Principe and Bioko Islands, the eastern Atlantic remains genetically unexplored. We present the first analysis of mitochondrial DNA (mtDNA) sequences (n = 28) of hawksbill juveniles in a foraging aggregation at the Cape Verde Islands, an archipelago located in the eastern Atlantic. The mean size (minimun curve carapace length) of the studied individuals was 42.45 cm.

  9. Experimental study about the impact of artificial lighting on loggerhead female nesting in Cape Verde.

    Abu Raya, Mara; Cruz, Eder; Marco, Adolfo; López-Jurado, Luis Felipe

    [EN] Artificial illumination of nesting beaches is one of the main threats to endangered sea turtle populations. Nocturnal lighting can impair female nest site selection and nesting success, as well as behavior and hatchling survival in their way from the nest surface to the seashore. The island of Boavista (Cape Verde) hosts the third largest loggerhead nesting aggregation in the world and the only relevant population in the Eastern Atlantic coast. Several threats such as fishing by-catch and female slaughter during nesting are severely threatening its conservation.

  10. Effects of light pollution by car headlights on loggerhead hatchlings in Cape Verde

    Santos-García, Vanesa; Marco, Adolfo; López-Jurado, Luis Felipe

    [EN] Many sea turtle nesting areas are experiencing a tremendous growth in tourism during the last decades that will likely continue in the near future. Many touristic activities involve light pollution by the increasing presence of vehicles close or even over the beaches. Vehicles can drive towards or along the beaches and even stay with the lights turned on illuminating during prolonged periods of time significant zones with sea turtle nesting activity. Thus, it is important to evaluate the impact of car light pollution on both nesting females and newborns in their search of the sea.

  11. Pathogenic effect of microorganisms on loggerhead eggs

    Abella Pérez, Elena; Marco, Adolfo; Diéguez-Uribeondo, Javier; López-Jurado, Luis Felipe

    [EN] Different types of fungi and bacteria have been isolated from hatched and non-hatched as well as failed and non-failed eggs in natural sea turtles nests (Marco et al. 2006, Phillott and Parmenter, 2001, Phillott et al. 2001). Microbiota infections are common in artificial incubation activities and they seem to have an important negative impact on embryo development (Phillott, 2002). However, no clear evidences of their pathogenic effects have been described. The aim of this study was to investigate whether fungi and bacteria represent pathogenic agents to sea turtle eggs, and to assess whether there exists a specific period during...

  12. Monitoring and conservation of the largest loggerhead turtle (Caretta caretta) nesting population in Africa: successes and challenges.

    Varo Cruz, Nuria; López, Pedro; Vázquez, Cristina; Ballell-Valls, Lluis; Cejudo, Daniel; López-Jurado, Luis Felipe

    [EN] The Republic of Cape Verde is situated about 500 km off the coast of Senegal, West Africa. The islands of Sal, Boa Vista and Maio constitute the Eastern group and harbour the most important nesting beaches for loggerhead turtles in the Archipelago. During 1998-2004 nesting seasons, fieldwork has been focused on the eastern beaches of Boa Vista and, occasionally, in other beaches of Boa Vista and in the islands of Maio, Sal and Santa Luzia. The main study area includes a total extension of 3.1 km of suitable nesting beaches. All through these years, a tagging program has been...

  13. The size of the loggerhead nesting females in the Cape Verde islands

    Ballell-Valls, Lluis; López-Jurado, Luis Felipe

    [EN] The recently discovered nesting colony of Caretta caretta at the island ofBoavista (Cape Verde Islands, West Africa, FIGURE 1) is being subject ofresearch since 1998. A total number of 1,391 different females have been tagged during the 1998, 1999 and 2000 nesting seasons. Although more data are needed, these islands may represent one ofthe most important populations for the species in the North Atlantic (Brongersma, 1982; Ross, 1995; López-Jurado & Andreu, 1998). The present study shows a comparative analysis between the morphometric data collected at Boavista during the last 2000 nesting season and those recorded in the 1998 and...

  14. Injuries observed in nesting females of loggerhead turtles on Boavista island (Cabo Verde Archipelago)

    Vázquez, Cristina; Varo Cruz, Nuria; López, Óscar; Liria-Loza, Ana; López-Jurado, Luis Felipe

    [EN] Different kinds of physical anomalies are frequently observed in any sea turtle breeding population. Nesting beaches are an excellent place to study the injuries and defects that occur in adult females. The archipelago of Cape Verde is situated about 500 km of Senegal, West Africa. Boavista is the eastern most island and may constitute the most important nesting area for the loggerhead turtle in the archipelago. The studies conducted from 1998 to 2004 indicate that Cape Verde might account for one of the most important loggerheads populations in the eastern Atlantic. The nesting females in Boavista were surveyed during...

  15. Loggerhead nesting trend in three beaches of Boavista, Cape Verde archipelago

    Liria-Loza, Ana; Varo Cruz, Nuria; Medina Suárez, María E.; Jiménez Bordón, Saray; López-Jurado, Luis Felipe

    [EN] Nesting beach surveys are the most widely implemented monitoring tool in use by the global sea turtle community and are an important component of a comprehensive program to assess and monitor the status of sea turtle populations. These assessments are necessary to evaluate the effects of recovery and conservation activities that are being implemented at all life history stages. Monitoring techniques employed on nesting beaches range from highly structured standardized sampling to “snapshots” of nesting activity within a nesting season. Very long-term nest counts data (more than twenty years) were analyzed for some turtle populations.

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

    Pérez García, Héctor; García Cerdá, Rosa María; Fernández Gil, Belén; Marco, Adolfo; Abu Raya, Mara; López-Jurado, Luis Felipe

    [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.

  17. Las puestas comunales de Hemidactylus boavistensis en la isla de Sal (Archipiélago de Cabo Verde)

    López-Jurado, Luis Felipe; Hernández-Acosta, C. Nayra; Geniez, Philippe; Mateo, José Antonio

    [ES]De acuerdo con Pough (1973), los requerimientos metabólicos de un saurio de pequeño tamaño determinan que su dieta deba ser básicamente insectívora. El mismo autor añadía que cuando el lagarto sobrepasa un determinado tamaño esa dieta basada en el consumo exclusivo de artrópodos ya no va a permitirle cubrir sus necesidades energéticas básicas y debe, por eso, buscar alternativas. Aunque en términos generales muchas especies se ajustan bastante bien a estas “reglas” ecofisiológicas, en los últimos 25 años han sido numerosos los trabajos publicados en los que se han recogido ejemplos que contravienen las previsiones de ese modelo, especialmente cuando...

  18. ¿Realmente importa tanto el tamaño? I: La dieta de las dos especies del género Tarentola de la Isla de Raso (Cabo Verde)

    Mateo, José Antonio; Geniez, Philippe; Hernández-Acosta, C. Nayra; López-Jurado, Luis Felipe

    [ES] La isla de Sal es, por su escaso relieve y por su posición geográfica, una de las islas más áridas del archipiélago de Cabo Verde (Chevalier, 1935). En ese escenario casi desértico vive Hemidactylus boavistensis, un geco endémico de las islas de Sal, Boavista y algunos islotes adyacentes (Arnold et al., 2008; Vasconcelos et al., 2013). Se trata de un saurio de pequeño tamaño (hasta 50 mm de longitud hocico cloaca; Figura 1a) relativamente abundante que durante el día suele refugiarse debajo de las piedras que descansan sobre el sustrato generalmente arenoso de la isla.

  19. ¿Realmente importa tanto el tamaño? II: La dieta de dos especies del género Tarentola en el Sáhara Occidental

    López-Jurado, Luis Felipe; Geniez, Philippe; Hernández-Acosta, C. Nayra; Mateo, José Antonio

    [ES] La Seguiat el Hamra es una cuenca hidrográfica árida situada en el extremo occidental del desierto del Sáhara. Si en su desembocadura la influencia del Océano Atlántico determina temperaturas tamponadas y cierta humedad ambiental, al este de Smara (26º44’29”N / 11º40’24”O) las condiciones bioclimáticas se endurecen (Ozenda, 1991), provocando un significativo cambio en la composición de las comunidades de vertebrados (Valverde, 1957; Geniez et al., 2004).

  20. Lost at sea: Genetic, oceanographic and meteorological evidence for storm-forced dispersal

    Monzón Argüello, Catalina; Dell’ Amico, F.; Morinière, P.; Marco, Adolfo; López-Jurado, Luis Felipe; Hays, Graeme; Scott, Rebecca; Marsh, Robert; Lee, Patricia

    [EN] For many species, there is broad-scale dispersal of juvenile stages and/or long-distance migration of individuals and hence the processes that drive these various wide-ranging move- ments have important life-history consequences. Sea turtles are one of these paradigmatic long-distance travellers, with hatchlings thought to be dispersed by ocean currents and adults often shuttling between distant breeding and foraging grounds. Here, we use multi- disciplinary oceanographic, atmospheric and genetic mixed stock analyses to show that juvenile turtles are encountered ‘downstream’ at sites predicted by currents. However, in some cases, unusual occurrences of juveniles are more readily explained by storm events and...

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