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Alfaro E.J.,Research Center en Ciencias del Mar y Limnologia | Alfaro E.J.,University of Costa Rica | Cortes J.,Research Center en Ciencias del Mar y Limnologia | Cortes J.,University of Costa Rica | And 8 more authors.
Revista de Biologia Tropical | Year: 2012

Bahía Culebra, Golfo de Papagayo, Costa Rica is a seasonal upwelling area. To determine the relationship of climate and the subsurface temperature variability at Bahía Culebra, we analyzed nine records of sea subsurface temperature from the Bay, continuously recorded from 1998 to 2010. The analysis characterized the annual cycle and explored the influence of different climate variability sources on the subsurface sea temperature and air temperature recorded in Bahía Culebra. Data from an automatic meteorological station in the bay were studied, obtaining the annual and daily cycle for air surface temperature and wind speed. Sea surface temperature (SST) trend from 1854 to 2011 was calculated from reanalysis for the region that coverts 9-11°N, 85-87°W. Because of the positive SST trend identified in this region, results showed that annual and daily cycles in Bahía Culebra should be studied under a warming scenario since 1854, that is coherent with the global warming results and its climate variability is influenced by El Niño-Southern Oscillation (ENSO) in the Equatorial Pacific and by atmospheric forcing triggered by climate variability with Atlantic Ocean origin, because warm (cold) events in Bahía Culebra tend to occur in concordance with positive & negative (negative & positive) anomalies in Niño 3.4 (NAO) index.


Seguro I.,University of Cádiz | Garcia C.M.,University of Cádiz | Papaspyrou S.,University of Cádiz | Galvez J.A.,University of Cádiz | And 9 more authors.
Regional Studies in Marine Science | Year: 2015

Microplankton organisms are an important link in the transfer of matter and energy between the benthic-pelagic microbial food web and higher trophic levels in estuaries. Although tropical estuaries are among the most productive aquatic systems globally, information on the spatial and seasonal dynamics of microplankton in such systems is scarce. In order to identify which variables control microplankton abundance and community structure a number of environmental variables were measured along the tropical Gulf of Nicoya (Costa Rica) during the rainy and dry seasons (2011-2012). The Tempisque River was a major source of nutrients and turbidity and thus imposing a clear gradient along the estuary. Chlorophyll a (chl a) concentration was highest in the middle of the estuary (2.7-20 mg m-3), where turbidity decreased. The microplankton comprised mainly diatoms (88%) and dinoflagellates (8%). Multivariate analysis revealed five different microplankton assemblages associated with a seasonal and riverine-marine gradient, and supporting an ecotone model at the estuary head that shifts to an ecocline model for the rest of the estuary. Our results suggest that primary producers in the estuary were mainly limited by light rather than nutrients. © 2015 Elsevier B.V.


Garcia-Mendez K.,University of Costa Rica | Camacho-Garcia Y.E.,University of Costa Rica | Camacho-Garcia Y.E.,Research Center en Ciencias del Mar y Limnologia
Revista de Biologia Tropical | Year: 2016

The molluscan fauna of Isla del Coco has recently been well documented, but the heterobranch sea slugs, traditionally called “opisthobranchs”, remain poorly known. We report 13 new records, increasing the total to 40 species. Of the 13 newly discovered species, the following species had not been previously recorded along the Pacific Costa Rican mainland: Berthella californica (Dall, 1900), Peltodoris rubra (Bergh, 1905), Dendrodoris albobrunnea Allan, 1933, Doriopsilla cf. spaldingi Valdés & Behrens, 1998, Glaucus cf. marginatus (Reinhardt & Bergh, 1864), and Flabellina sp. Additionally, we report Peltodoris rubra, previously known from the Indo-Pacific, for the first time in the Eastern Tropical Pacific. © 2016, Universidad de Costa Rica. All rights reserved.


Naranjo-Elizondo B.,Research Center en Ciencias del Mar y Limnologia | Naranjo-Elizondo B.,University of Costa Rica | Espinoza M.,Research Center en Ciencias del Mar y Limnologia | Espinoza M.,University of Costa Rica | And 5 more authors.
Journal of Applied Ichthyology | Year: 2016

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% PSIRI i) followed by teleosts (28.2% PSIRI i), stomatopods (10.8% PSIRI i), and crabs (3.3% PSIRI i). 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% PSIRI i); mature individuals consumed a large proportion of teleosts and stomatopods, which together contributed to over 91.0% PSIRI i. 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. © 2016 Blackwell Verlag GmbH.


Espinoza M.,Research Center en Ciencias del Mar y Limnologia | Espinoza M.,University of Costa Rica | Clarke T.M.,Research Center en Ciencias del Mar y Limnologia | Villalobos-Rojas F.,Research Center en Ciencias del Mar y Limnologia | And 2 more authors.
Journal of Fish Biology | Year: 2012

Stomachs from 511 Raja velezi and 340 Mustelus henlei captured as by-catch in the commercial trawling fishery (2010-2012) were analysed to examine diet composition, ontogenetic shifts and degree of dietary overlap between species life stages in the Pacific Ocean of Costa Rica. Shrimps were the most important prey categories in the diet of R. velezi, while teleosts and cephalopods dominated the diet of M. henlei. Diet comparisons between different stages of R. velezi and M. henlei revealed clear ontogenetic dietary shifts: crustaceans (mainly shrimps, crabs and stomatopods) dominated the diet of immature individuals, and adults had a higher proportion of teleosts. The results suggest that R. velezi is an epibenthic predator that specializes in shrimps during early life stages, and to a lesser extent, teleosts as it matures, while M. henlei is an opportunistic predator with a highly diverse diet consisting of teleosts, cephalopods, shrimps and stomatopods. This study also found little evidence of dietary overlap between species or life stages and suggests that intra- and interspecific competition between R. velezi and M. henlei may be reduced by: (1) diet specialization in immature stages of R. velezi, (2) ontogenetic dietary shifts between immature and mature individuals, (3) prey-size selectivity in larger individuals of R. velezi and (4) differences in depth utilization in overlapping geographical regions. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.


Alfaro E.J.,Research Center en Ciencias del Mar y Limnologia | Alfaro E.J.,University of Costa Rica | Cortes J.,Research Center en Ciencias del Mar y Limnologia | Cortes J.,University of Costa Rica
Revista de Biologia Tropical | Year: 2012

Bahía Culebra, at Gulf of Papagayo on the north Pacific coast of Costa Rica, is an area of seasonal upwelling where more intense cooling events may occur during some boreal winter weeks mainly. To study these extreme cool events, records of nine sea subsurface temperature stations from 1998 to 2010 were analyzed. Five events associated with extremely cool temperatures in this region were identified from these records and taken as study cases. Sea temperatures decreased about 8-9°C during these events and occurred while cold fronts were present in the Caribbean, with strong trade wind conditions over Central America. These strong wind conditions may have favored the offshore displacement of the sea surface water. The axis of Bahía Culebra runs northeastsouthwest, a condition that favors and triggers cool water events, mainly because the displaced water is replaced by water from deeper levels.


Lizano O.G.,Research Center en Ciencias del Mar y Limnologia | Alfaro E.J.,Research Center en Ciencias del Mar y Limnologia | Matarrita A.S.,University of Costa Rica
Revista de Biologia Tropical | Year: 2012

In order to evaluate metal enrichment in sediments, a method is proposed and tested in Bahia Culebra and the Golfo de Nicoya, Costa Rica through the normalization of the elements against aluminum, and by linear regréa Culebra did not satisfy the tests of normalization and linear regression, indicating a nonnatural distribution or enrichment of these elements in this region. In the Golfo de Nicoya the elements copper, zinc, rubidium and the strontium did not satisfy the test of normality or the linear regression with respect to aluminum, indicating a possible enrichment of these elements. The majority of the concentrations of the elements in two sample sites, with the exception of chromium, are within the natural ranges in rocks or clays of marine sediments, and within the concentration ranges of other studies done in these same regions. Chromium has average values beyond the natural concentrations, the values of some samples in the Golfo de Nicoya are up to 10 times greater than the concentration value of a typical bay with high contamination of this element.


Espinoza M.,Research Center en Ciencias del Mar y Limnologia | Clarke T.M.,Research Center en Ciencias del Mar y Limnologia | Villalobos-Rojas F.,Research Center en Ciencias del Mar y Limnologia | Wehrtmann I.S.,Research Center en Ciencias del Mar y Limnologia
Journal of Fish Biology | Year: 2013

The diet and diel feeding behaviour of the banded guitarfish Zapteryx xyster were examined along the Pacific coast of Costa Rica. A sample of 235 stomachs was collected between March 2010 and December 2011 as part of an ongoing shrimp-trawl by-catch monitoring programme. Samples from multiple day and night periods allowed testing the hypothesis that Z. xyster is more active at night, thus increasing the amount of food intake during night-time. Overall, shrimps (52·3% prey-specific index of relative importance, PSIRIi) and teleosts (27·2% PSIRIi) were the most important prey categories. Juveniles fed primarily on smaller shrimps (Solenocera spp.), while adults shifted to larger prey. The amount of food consumed (as % of bodymass) by juvenile and adult Z. xyster increased significantly between 0400 and 1200 hours, while the proportion of empty stomachs decreased during the same time interval. These findings contradict the hypothesis that Z. xyster is more active and feeds at night. The study also revealed that Z. xyster, particularly juveniles, forage on several shrimp species and overlap spatially with the Costa Rican bottom-trawl fisheries. This has important management and conservation implications as Z. xyster may be experiencing high by-catch rates, and because of their life history is presumed to be vulnerable to intense levels of exploitation. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

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