Genetic connectivity of an endangered shark across nursery areas from the Eastern Tropical Pacific

Defining demographically independent units and understanding gene flow between them is essential for managing and conserving exploited populations. The scalloped hammerhead shark, Sphyrna lewini , is a coastal semi-oceanic species found worldwide in tropical and subtropical waters. Pregnant females give birth in shallow coastal estuarine habitats that serve as nursery grounds for neonates and small juveniles, and adults move offshore and become highly migratory. We evaluated the population structure and connectivity of S. lewini in coastal areas across the Eastern Tropical Pacific (ETP) using both sequences of the mitochondrial DNA control region (mtCR) and nuclear-encoded microsatellite loci. The mtCR defined two genetically discrete geographic groups: the Mexican Pacific and the central-southern Eastern Tropical Pacific (Guatemala, Costa Rica, Panamá, and Colombia). Overall, the mtCR data showed low levels of haplotype diversity ranged from 0.000 to 0.608, while nucleotide diversity ranged from 0.000 to 0.0015. A more fine-grade population structure analysis was detected using microsatellite loci where Guatemala, Costa Rica, and Panamá differed significantly. Genetic diversity analysis with nuclear markers revealed an observed heterozygosity ranging from 0.68 to 0.71 and an allelic richness from 5.89 to 7.00. Relatedness analysis revealed that individuals within nursery areas were more closely related than expected by chance, suggesting that S. lewini may exhibit reproductive philopatric behaviour within the ETP. Findings of at least two different management units, and evidence of philopatric behaviour call for intensive conservation actions for this critically endangered species in the ETP.Universidad de Costa Rica/[801-B6-214]/UCR/Costa RicaNational Secretary of Science and Technology/[FID-156]/SENACYT/EcuadorThe Phoenix Zoo/[no.33297]//Estados UnidosPADI Foundation/[no.32809]//Estados UnidosRufford Foundation/[no.22366-1]//Reino UnidosWaitt Foundation/[no.33297]//Estados UnidosFundación Reserva Ojochal/[]//Costa RicaThe Whitley Fund for Nature/[]/WFN/Reino UnidoSandler Family Foundation/[]//Estados UnidosOsa Conservation/[]//Costa RicaUCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de BiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Conservación y actividad reproductiva de tortuga lora (Lepidochelys olivacea) en la playa de anidación solitaria Punta Banco, Pacifico Sur de Costa Rica. Recomendaciones de manejo a través de dieciséis años de monitoreo

Sea turtle nesting activity was monitored in Punta Banco, South Pacific Costa Rica uninterruptedly for sixteen years, accompanied by conservation activities such as nest relocation in hatcheries. Hatching success evaluations were held for “in situ” and relocated nests. We hereby evaluate the reproductive biology of the olive ridley sea turtle (Lepidochelys olivacea), by far the most common turtle sea turtle nesting in Punta Banco (98% of observed turtles). Daily monitoring of nesting activities was held every year from July to December, from 1996 to 2011. We tagged a total of 1 239 turtles and recorded 4 130 nesting events. The number of recorded nesting events per nesting season ranged from 239 in 1996 to 402 in 1999, whereas the number of observed females ranged from 18 in 1996 to 146 in 1999. Nesting females had an average curved carapace length of 66.8cm and an average curve carapace width of 70.7cm. The average clutch size was 96.7, with an observed frequency of 1.07 nests/female and an nesting interval of 19.95 days. Hatching success of “in situ” nests was 61.38%, whereas hatching success for nests relocated into hatcheries was 77.9%.  The L. olivacea population in Punta Banco beach displays a a positive trend. Se realizó un monitoreo de la actividad de anidación de tortugas marinas en Punta Banco, Pacífico Sur de Costa Rica, de forma ininterrumpida por diez y seis años, acompañado por actividades de conservación como la relocalización de los nidos en viveros. Se realizaron análisis de éxito de eclosión para nidos “in situ” y en vivero. Evaluamos por este medio la biología reproductiva de la tortuga lora (Lepidochelys olivacea), por mucho la tortuga más común que anida en Punta Banco (98% de las tortugas observadas). Entre 1996 y 2011, se llevó a cabo el monitoreo diario de las actividades de anidación de julio a diciembre. Marcamos un total de 1 239 tortugas L. olivacea y registramos 4 130 eventos de anidación. El total de anidaciones para L. olivacea varió de 239 en el año 1996 a 402 en 1999, mientras que el número de hembras avistadas varió de 18 en 1996 a 146 en 1999. Las hembras presentaron un largo curvo del caparazón promedio de 66.8cm y ancho curvo de caparazón promedio de 70.7cm. La media para el tamaño de las nidadas fue de 96.7 huevos, con una frecuencia de puesta observada de 1.07 nidos/hembra y un intervalo de puesta observado de 19.95 días. El éxito de eclosión de nidos “in situ” fue de 61.38%, mientras que el éxito de nidos relocalizados en viveros fue de 77.9%. La población de L. olivacea en Punta Banca muestra una tendencia positiva.

New foraging grounds for hawksbill (Eretmochelys imbricata) and green turtles (Chelonia mydas) along the northern Pacific coast of Costa Rica, Central America

Existe poca información disponible sobre los sitios de forrajeo de las poblaciones de tortugas marinas del Pacífico Oriental, lo cual dificulta el diseño de estrategias de conservación tanto en el ámbito nacional como internacional.  Realizamos observaciones en cinco sitios a lo largo del Pacífico Norte de Costa Rica (Cabo Blanco, Punta Coyote, Punta Pargos, Punta Argentina y Bahía Matapalito) entre el 2010-2013, utilizando redes de enmalle tortugueras con luz de malla de 45 cm, con el objetivo de explorar y documentar nuevos sitios de forrajeo.  Estandarizamos la Captura Por Unidad de Esfuerzo (CPUE) como tortugas capturada por 100m de relinga superior por hora de inmersión, el cual varió de 0.06 en Punta Pargos hasta 0.58 en Bahía Matapalito para tortugas carey (Eretmochelys imbricata), y de 0.01 en Punta Coyota hasta 0.10 en Cabo Blanco para tortugas verde del Pacífico (Chelonia mydas).  Encontramos rangos de tamaño específicos por sitio para E.imbricata en Bahía Matapalito y Cabo Blanco, con promedio ± Desviación Estándar (SD) del Largo Curvo de Caparazón (CCL) de 42.46 ± 17.66cm y 61.25±13.08cm respectivamente.  Tan solo se encontró un individuo en los demás sitios con CCL de 49.6cm hasta 60.5 cm.  Se capturaron tortugas verde en tres de los sitios observados, con CCL de 67.67±19.44cm en Cabo Blanco, 69.40±9.40cm en Punta Coyote. y un único individuo en Bahía Matapalito con un CCL de 56.2cm. La ausencia de clases de tamaño de adultos para E.imbricata, así como de clases de tamaño de juveniles para la tortuga verde del Pacífico, enfatiza la complejidad de la distribución específica por especies durante las distintas fases de vida de las tortugas marinas en el Pacífico Oriental, y la necesidad emergente de implementar monitoreos a largo plazo en diferentes sitios a lo largo del Pacífico Norte del país para comprender la conectividad entre hábitats. El presente estudio revela la existencia de sitios de forrajeo frágiles desprotegidos para la tortuga carey y verde en el Pacífico norte de Costa Rica, y sirve de guía para futuras iniciativas de investigación para fortalecer estrategias de conservación en el ámbito nacional e internacional.Scarce information is available on the foraging grounds of Eastern Pacific sea turtle populations, which hinders the design of efficient national and regional conservation strategies. We surveyed five locations along Costa Rica’s North Pacific between 2010-2013 using 45cm mesh turtle tangle nets, with the aim to explore and document new foraging sites (Cabo Blanco, Punta Coyote, Punta Pargos, Punta Argentina, and Bahía Matapalito). We standardized Catch Per Unit Effort (CPUE) as turtles caught per 100m of headrope length per one-hour soak time, which ranged from 0.06 at Punta Pargos to 0.58 in Bahía Matapalito for hawksbill turtles (Eretmochelys imbricata), and from 0.01 in Punta Coyote to 0.10 in Cabo Blanco for Eastern Pacific green turtles (Chelonia mydas). We found site-specific size ranges for E. imbricata with mean ± Standard Deviation (SD) Curve Carapace Lengths (CCL) of 42.46±17.55cm in Bahía Matapalito and 61.25±13.08cm in Cabo Blanco. Only one individual was found at each of the other sites with CCLs from 49.6cm to 60.5cm. Green turtles were found at three of the surveyed locations with mean CCLs of 67.67±19.44cm at Cabo Blanco and 69.40±9.40cm at Punta Coyote and only one individual at Bahía Matapalito with a CCL of 56.2cm. The absence of adult size classes for E. imbricata and of small juvenile size classes for C. mydas at most of these sites stresses the complexity of species-specific distribution during different life stages in the Eastern Pacific and the urgent need to implement long-term monitoring at different coastal sites along the North Pacific to understand habitat connectivity. This study reveals the existence of fragile, non-protected foraging grounds for hawksbill and green turtles in Costa Rica’s North Pacific, and serves as a guide for future research initiatives to strengthen national and regional conservation strategies. Rev. Biol. Trop. 62 (Suppl. 4): 109-118. Epub 2014 Diciembre 01

Energy flow structure and role of keystone groups in shallow water environments in Isla del Coco, Costa Rica, Eastern Tropical Pacific

Isla del Coco (Costa Rica) forms part of the five oceanic islands of the Eastern Tropical Pacific and is well known for its high biodiversity and great endemism. While several marine biological and oceanographical surveys have been conducted around the island over the past 35 years, an integrated, systematic view of the shallow water system is lacking as is an assessment of the impact of illegal fisheries. The aim of the study was thus to identify the main biological compartments of the Isla del Coco system and to quantify its energy flow structure through the development of a trophic model for the shallow water environments (≤30 m). With the software Ecopath with Ecosim, and based on the model structure previously used for Darwin and Wolf islets in the Galápagos Archipelago, a trophic model was developed using information from several field surveys and additional data from similar systems. The total biomass of the Isla del Coco system (1,972.25 t km−2) was mainly comprised of high trophic level species such as hammerhead shark, pelagic predatory fish and other sharks. The reef ecosystem is in a healthy (relatively undisturbed) state and dominated by large apex predators and mesopredators. Of the keystone groups identified (toothed cetaceans, tiger sharks, other sharks, benthic omnivorous fish and pelagic predatory fish), toothed cetaceans and tiger sharks were identified as having the strongest influence on the structure and diversity of the community through direct and indirect interactions. The Isla del Coco ecosystem presents a higher biomass than a similar system in the Galápagos archipelago, likely due to lower fishing pressure and higher system maturity.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biologí