Talla de madurez sexual del congrio rosado (Ophidiidae: Brotula clarkae): una especie de importancia comercial en el Pacífico de Costa Rica

The deep-water shrimp fishery is of great commercial importance along the Pacific coast of Latin America. In Costa Rica, shrimp resources have declined considerably over the last decade. Therefore, fisheries have shifted towards teleost species such as the Pacific bearded brotula Brotula clarkae. Little is known about the biology and life history of this species, which is becoming increasingly valuable to artisanal and semiindustrial fishers in Costa Rica. A sample of 348 B. clarkae was obtained along the Pacific coast of Costa Rica between March 2011 and July 2012 to obtain baseline information of this species. The results revealed that the size at sexual maturity of B. clarkae was 71.9 cm TL, considerably higher than previously reported for South American populations. Since the size at maturity may vary between populations in different geographic locations, detailed information of the reproductive biology of widely distributed species such as B. clarkae is critical for developing effective management approaches.La pesca de camarón de aguas profundas es de gran importancia comercial en la costa Pacífica de Latinoamérica. En Costa Rica, el recurso camarón ha disminuido considerablemente durante la última década. Como consecuencia, la pesquería ha comenzado a explotar otras especies como, el congrio rosado Brotula clarkae. Poco se sabe de la biología de esta especie con valor comercial en las pesquerías artesanales e industriales de Costa Rica. Una muestra de 348 B. clarkae fue obtenida a lo largo de la costa Pacífica de Costa Rica entre marzo 2011 y julio 2012 para obtener información base de esta especie. La talla de madurez sexual fue 71.9 cm TL, siendo considerablemente mayor que la reportada previamente para poblaciones de Sudamérica. Dado que la talla de madurez sexual puede variar entre poblaciones de diferentes áreas geográficas, información acerca de la biología reproductiva de una especie tan ampliamente distribuida es crucial para diseñar estrategias adecuadas de manejo.Universidad de Costa Rica/[VI project N° 808-B0-536]/UCR/Costa RicaUniversidad de Costa Rica/[VI project N° 111-A4-508]/UCR/Costa RicaConsejo Nacional de Ciencia y Tecnología/[]/CONICIT/Costa RicaUCR::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

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

Sondeo ecológico rápido de las comunidades de peces tropicales en un área de explotación minera en Costa Rica

El impacto de las minerías de oro ha generado una gran preocupación por el deterioro de los hábitats acuáticos y la fragmentación de los sistemas naturales. Las perturbaciones antropogénicas sobre la estructura y heterogeneidad del sistema pueden influir en la estabilidad de las comunidades acuáticas. Sondeos ecológicos rápidos (1996, 2002, 2007) fueron empleados para determinar la estructura, composición y distribución de las comunidades de peces tropicales en varios ríos y quebradas del área de una minería de oro en el Cerro Crucitas, Costa Rica. Además, la composición de especies y abundancia relativa se relacionó con la estructura del hábitat. Se registró un total de 35 especies, de las cuales la sardina Astyanax aeneus (Characidae) y la olomina Alfaro cultratus (Poeciliidae) fueron las especies más abundantes (71%). La mayor riqueza de especies se observó en el Caño Crucitas (s = 19) y la quebrada Minas (s = 18). Se encontró una gran variación en la estructura y composición de las comunidades de peces, principalmente, en el río Infiernillo y Minas (? = 0.0, F132, 66 = 2.24, p < 0.001). La presencia o ausencia de algunas especies como Gobiomorus dormitor, Rhamdia nicaraguensis, Parachromis loiseillei y Atractosteus tropicus explicaron la mayor parte de la variación espacial entre sitios. La heterogeneidad estructural del hábitat también contribuyó a explicar diferencias importantes entre sitios (? = 0.004, F60, 183 = 5.52, p < 0.001). El tipo de sustrato (blando y duro) y la estructura del hábitat (elevación, ancho y profundidad) explicaron la mayor parte de la variabilidad observada en el río Infiernillo, el Caño Crucitas y la quebrada Tamagá. Además se encontró una asociación significativa entre las especies y la estructura del hábitat. Este estudio evidencia la complejidad en la estructura y composición de especies que habitan el área de la minería de oro, y acentúa la importancia de la heterogeneidad estructural del hábitat en la dinámica de las comunidades de peces tropicales. El deterioro y fragmentación de los hábitats acuáticos en el área de una minería de oro pueden tener un fuerte efecto negativo sobre la estructura de las comunidades de peces tropicales

Sondeo ecológico rápido de las comunidades de peces tropicales en un área de explotación minera en Costa Rica

El impacto de las minerías de oro ha generado una gran preocupación por el deterioro de los hábitats acuáticos y la fragmentación de los sistemas naturales. Las perturbaciones antropogénicas sobre la estructura y heterogeneidad del sistema pueden influir en la estabilidad de las comunidades acuáticas. Sondeos ecológicos rápidos (1996, 2002, 2007) fueron empleados para determinar la estructura, composición y distribución de las comunidades de peces tropicales en varios ríos y quebradas del área de una minería de oro en el Cerro Crucitas, Costa Rica. Además, la composición de especies y abundancia relativa se relacionó con la estructura del hábitat. Se registró un total de 35 especies, de las cuales la sardina Astyanax aeneus (Characidae) y la olomina Alfaro cultratus (Poeciliidae) fueron las especies más abundantes (71%). La mayor riqueza de especies se observó en el Caño Crucitas (s = 19) y la quebrada Minas (s = 18). Se encontró una gran variación en la estructura y composición de las comunidades de peces, principalmente, en el río Infiernillo y Minas (&#955; = 0.0, F132, 66 = 2.24, p Rapid ecological assessment of tropical fish communities in a gold mine area of Costa Rica. Gold mining impacts have generated a great concern regarding aquatic systems and habitat fragmentation. Anthropogenic disturbances on the structure and heterogeneity of a system can have an important effect on aquatic community stability. Ecological rapid assessments (1996, 2002, and 2007) were employed to determine the structure, composition and distribution of tropical fish communities in several rivers and smaller creeks from a gold mining area in Cerro Crucitas, Costa Rica. In addition, species composition and relative abundance were related with habitat structure. A total of 35 species were registered, among which sardine Astyanax aeneus (Characidae) and livebearer Alfaro cultratus (Poeciliidae) were the most abundant fish (71%). The highest species richness was observed in Caño Crucitas (s = 19) and Minas Creek (s = 18). Significant differences in fish communities structure and composition from Infiernillo river and Minas creek were observed (&#955; = 0.0,F132, 66 = 2.24, p < 0.001). Presence and/or absence of certain species such as Dormitor gobiomorus, Rhamdia nicaraguensis, Parachromis loiseillei and Atractosteus tropicus explained most of the spatial variation among sites. Habitat structure also contributed to explain differences among sites (&#955; = 0.004, F60, 183 = 5.52, p < 0.001). Substratum (soft and hard bottom types) and habitat attributes (elevation, width and depth) explained most of the variability observed in Infiernillo River, Caño Crucitas and Tamagá Creek. In addition, a significant association between fish species and habitat structure was observed. This study reveals a high complexity in tropical fish communities that inhabit a gold mine area. Furthermore,it highlights the importance of habitat heterogeneity in fish community dynamics. The loss and degradation of aquatic systems in Cerro Crucitas can have a strong negative effect on fish community structure and composition of local species. A better understanding of the use of specific habitats that serve as essential fish habitats can improve tropical fish conservation and management strategies, thus increasing local diversity, and thereby, the biological importance of the area. Rev. Biol. Trop. 56 (4): 1971-1990. Epub 2008 December 12

Estructura de las comunidades de peces de arrecife en las Islas Catalinas y Playa Ocotal, Pacífico Norte de Costa Rica

The reefs are heterogeneous systems that maintain a high diversity of organisms. Fish community structure varies within and among reefs, so it would be expected that reef structure and heterogeneity should affect fish communities inhabiting reefs. Four reef patches at Catalinas Islands (Sur, La Pared, Roca Sucia and Sombrero) and one in Ocotal beach (10°28’45” N; 85°52’35” W) were studied with visual censuses (July-December 2003). The structure and composition of fishes between Catalinas Islands and Ocotal beach were different, and habitat structure and composition explain most of the variance founded. The presence of the fleshy algae Caulerpa sertularioides in Ocotal, and the corals Tubastrea coccinea and Pocillopora spp. at Catalinas Island explained the variability among sites and how it affected fish community structure and composition. The butterfly fish Johnrandallia nigrirostris, damselfish Microspathodon dorsalis, and surgeon fish Prionurus punctatus were directly correlated with the ahermatipic coral Tubastrea coccinea in Roca Sucia reef, while the angel fish Holacanthus passer was associated to reefs with a major percentage of rocky substrate. Other species such as the damselfish Abudefduf troschelli and Halichoeres dispilus were more abundant at Ocotal, where the algae C. sertularioides dominated. The number and abundance of reef fishes was directly correlated with the rugosity index at the reefs of Roca Sucia and Ocotal, but not at reefs of La Pared and SombreroLos arrecifes son sistemas muy complejos, cuya heterogeneidad mantiene una gran diversidad de organismos. La estructura de las comunidades de peces que forman parte del arrecife varía dentro y entre arrecifes, y se esperaría que la heterogeneidad y estructura del arrecife vaya a influir en la estructura de las comunidades de peces que habitan. Se estudiaron cuatro arrecifes en las Islas Catalinas (Sur, La Pared, Roca Sucia y Sombrero) y uno en la Playa de Ocotal, Pacífico Norte de Costa Rica. Se encontraron diferencias claras en la estructura y composición de las comunidades de peces de arrecife en las Islas Catalinas y Playa Ocotal, y la estructura y composición del hábitat explicaron la mayor parte de la varianza. Ciertos atributos del arrecife como la presencia del alga Caulerpa sertularoides en Ocotal, así como los corales Tubastrea coccinea y Pocillopora spp., en las Islas Catalinas explicaron la variabilidad que existía entre los sitios y como afectaba a la estructura de la comunidad de peces de arrecife. La mariposa Johnrandalia nigrirostris, la damisela Microspathodon dorsalis y el cirujano Prionurus punctatus se correlacionaron directamente con el coral ahermatípico Tubastrea coccinea, en el arrecife de Roca Sucia, mientras que Holocanthus passer se asocio a arrecifes con un mayor porcentaje de sustrato rocoso. Otras especies como Abudefduf troschelli y Halichoeres dispilus se encontraban en mayor cantidad en el arrecife de Ocotal, en donde dominaba el alga Caulerpa sertularioides. Por último, el número y abundancia de peces de arrecife se correlacionó directamente con el índice de rugosidad del sustrato en los arrecifes de Roca Sucia y Ocotal, pero no así los de la Pared y Sombrero

Stomach content analyses of the threadfin anglerfish Lophiodes spilurus (Lophiiformes: Lophiidae) associated with deepwater shrimp fisheries from the central Pacific of Costa Rica

Our knowledge of deepwater ecosystems along the Pacific of Central America is extremely limited. We analyzed the diet composition of 200 adult specimens of Lophiodes spilurus ranging in size from 7.8 to 17.8 cm total length (TL). Samples were obtained from deep bottom trawls (depth: 105-238 m) along the central Pacific of Costa Rica. We calculated the percentage of number (% N), weight (% W), and occurrence (% O) of each food item encountered in the stomachs; based on this information, the Index of Relative Importance (IR) was calculated. Moreover, we estimated diet overlap for three different size classes ( 15.1 cm TL). The results revealed exclusively two groups of benthic prey items: crustaceans (30%) and teleost fish (70%) in their diet. The most frequent preys were pandalid shrimps Plesionika trispinus (% O = 17) and the fathom mora Physiculus rastrelliger (% O = 12). The greatest diversity and frequency of abundance of food items was observed in intermediate-sized individuals (10.1-15.0 cm TL). Small-sized L. spilurus ( 15.0 cm TL) preyed on large-sized stomatopods and teleost fish. There was a clear diet overlap between small and intermediate-sized L. spilurus (p 0.05). Our results suggest that L. spilurus feeds exclusively on crustaceans (Decapoda and Stomatopoda) and benthic teleost fish along the Pacific of Costa Rica. While small and large-sized individuals showed a more pronounced selectivity for certain prey items, the high diversity of benthic prey items observed in intermediatesized specimens suggest a more opportunistic foraging behavior

Elasmobranch bycatch associated with the shrimp trawl fishery off the Pacific coast of Costa Rica, Central America

Demersal sharks and rays are common yet vulnerable components of the bycatch in tropical bottom-trawl fisheries. Little is known about the elasmobranch assemblages associated with most of these fisheries, particularly within the eastern tropical Pacific. This study characterized the elasmobranch assemblage associated with the shrimp trawl fishery along the Pacific coast of Costa Rica. Between August 2008 and August 2012, 346 trawl hauls were conducted at depths of 18–350 m. These hauls resulted in a sample of 4564 elasmobranchs from 25 species and 13 families. The Panamic stingray (Urotrygon aspidura), rasptail skate (Raja velezi), brown smoothhound (Mustelus henlei), and witch guitarfish (Zapteryx xyster) accounted for more than 66% of the elasmobranch abundance within the bycatch. Depth was the main factor influencing the elasmobranch assemblage; species richness was significantly higher at depths <100 m than at other depths. Two groups of elasmobranchs were identified: the first was found in shallow waters (<50 m), and the second was observed at depths of 50–350 m. Sex and size segregation patterns are also influenced by depth. Moreover, we documented the shift of the bottomtrawl fishery toward shallow-water resources—a change that could be problematic considering that elasmobranch diversity is higher in shallow watersUniversidad de Costa Rica/[808-B0-536]/UCR/Costa RicaUniversidad de Costa Rica/[111-A4-508]/UCR/Costa RicaUCR::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

Feeding habits of the Pacific bearded brotula Brotula clarkae Hubbs, 1944 (Ophidiidae) along the Pacific coast of Costa Rica, Central America

The present study analyzed the diet composition, ontogenetic shifts and dietary overlap of Brotula clarkae in relation to stage of maturity and sex. Samples were collected from the trawling fishery along the Pacific coast of Costa Rica (2011–2012) at depths ranging from 41.4 to 168.3 m; however, over 80% of the sampled fish were obtained at depths between 50 and 75 m. Size ranged from 14.4 to 98.4 cm total length. Of the 323 analyzed stomachs, 44.3% were from males, 86% were from immature individuals, and 49.8% had at least one prey item. According to the prey-specific index of relative importance (PSIRI), decapod shrimps were the most important prey (57.6% PSIRIi) followed by teleosts (28.2% PSIRIi), stomatopods (10.8% PSIRIi), and crabs (3.3% PSIRIi). Male and female B. clarkae exhibited a high dietary overlap (CH = 0.94). Immature B. clarkae consumed primarily shrimps and crabs (71.5% of stomachs from immature specimens contained shrimps, which accounted for over 66.0% PSIRIi); mature individuals consumed a large proportion of teleosts and stomatopods, which together contributed to over 91.0% PSIRIi. Both immature and mature B. clarkae overlapped spatially with the commercial trawling fishery grounds along the Pacific coast of Costa Rica. However, juveniles feed predominantly on shrimps, suggesting that immature B. clarkae may be subjected to high fishing pressure as by-catch, making them particularly vulnerable to overexploitation.Universidad de Costa Rica/[VI-808-B0-536]/UCR/Costa RicaUniversidad de Costa Rica/[VI-111-A4-508]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Feeding ecology of common demersal elasmobranch species in the Pacific coast of Costa Rica inferred from stable isotope and stomach content analyses

Knowledge of the feeding ecology and trophic interactions of marine species is essential to understanding food web dynamics and developing ecosystem-based management approaches. Given that many top predatory fishes have experienced large population declines from coastal ecosystems, it is critical to understand the role of smaller, mesopredators in coastal food webs. This study used stomach content (SCA) and stable isotope analyses (SIA) of muscle tissue (δ13C, δ15N) to examine the feeding ecology of four common demersal elasmobranchs (Mustelus henlei, Raja velezi, Zapteryx xyster and Torpedo peruana) from the Pacific coast of Costa Rica, Central America. Specifically, we investigated: (i) size- and sex-related changes in diet; (ii) dietary changes between seasons; (iii) dietary changes across depth and latitudinal gradients; and (iv) the degree of diet overlap among species. SCA showed that M. henlei, R. velezi and Z. xyster were feeding on a wide range of teleost and decapod species, whereas teleosts dominated the diet of T. peruana. Torpedo peruana had a lower prey diversity and dietary breath than the other species. Interestingly, SIA revealed a significantly larger isotopic niche breath in Z. xyster, indicating that SIA can provide a broader perspective of diet than SCA. Both SCA and SIA showed relatively low dietary overlap among species, except between R. velezi and Z. xyster which have a similar size, mouth morphology and potentially feeding behaviour. Latitude and size were identified as important drivers of the feeding ecology of elasmobranchs; however, their effect varied considerably among species and was often influenced by other factors such as sex and depth. Season had little influence on elasmobranch diet, but our data suggested that isotopic baseline values differ between geographic regions due to differences in local biogeochemical processes and/or prey availability, and possibly in response to seasonal nutrient fluctuations. This may also indicate that some of these elasmobranchs tend to use more localized habitats along the coast. The present study increased our understanding of the feeding ecology of common demersal elasmobranch species. Moreover, trophic information of elasmobranchs provided an important baseline record to understanding how trawling fisheries may impact demersal ecosystems in Costa Rica and the Central American region.Consejo Nacional de Ciencia y Tecnología de Costa Rica/[FI-449-10]/CONICIT/Costa RicaUniversidad de Costa Rica/[808-B0-536]/UCR/Costa RicaUniversidad de Costa Rica/[808-B1-547]/UCR/Costa RicaUniversidad de Costa Rica/[808-B1-537]/UCR/Costa RicaUniversidad de Costa Rica/[111-A4-508]/UCR/Costa RicaConservation International and MarViva/[]//Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Does Estuary Restoration Design Alter the Fine Scale Movements of Gray Smoothhounds (Mustelus californicus) in Southern California?

Restored estuaries in southern California are limited in size and shape by fragmentation from human development, which can in turn restrict habitat use. Thus, it is important to assess how habitat design affects how fish use restored estuaries. Acoustic telemetry tracking from prior studies revealed that Gray Smoothhounds (Mustelus californicus) used primarily the eelgrass ecotone and warm interior waters in Bolsa Chica Full Tidal Basin (BCFTB), a 1.48 km2 open-format marine dominated estuary. In this study, M. californicus utilized the Channel in Huntington Beach Wetlands Complex (HBWC), a smaller creek estuary. The Channel had more eelgrass than other available habitats but was also the coolest microhabitat, with temperatures below what M. californicus was found to select in BCFTB. Individuals may behaviorally thermoregulate by moving upstream, away from the HBWC Channel, during periods of incoming, cooler ocean water. Mustelus californicus translocated to different microhabitats within the HBWC selected the Channel habitat after the translocation regardless of where animals were released. Despite the large difference in available subtidal habitat between HBWC and BCFTB, no differences in patch size utilization distributions of M. californicus were observed. While individuals seem to shift between microhabitats based on temperature and eelgrass availability, the area size used by M. californicus appears to be the same within both sites despite the differences in overall size between sites. These results suggest that differences in microhabitat use may influence distribution patterns of M. californicus within each site, and therefore, shark abundance may vary with the restoration design (e.g. basin versus channel) and the size of the estuarine habitat. This information on habitat selection will be critical to planning future restorations on the Southern California coast.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR