Costa Rican Waters Research Articles

First record of the Clymene dolphin (Stenella clymene Gray, 1850) in Costa Rican waters

First record of the Clymene dolphin (Stenella clymene Gray, 1850) in Costa Rican waters

Trends and variability in local abundances of sailfish Istiophorus platypterus in Pacific waters of Costa Rica: Controls and effects on recreational fisheries

Fishing tourism represents a vital industry in Costa Rica, generating over US$520 million and attracting 150,000 tourists every year. The main objective of this study is to examine trends and variability in local abundances of sailfish Istiophorus platypterus, the main sportfish in Pacific waters of Costa Rica, and quantify the influence of environmental and anthropogenic factors. We compiled and analyzed sailfish information collected from sportfishing operations. Sailfish abundances were examined in relation to environmental conditions and commercial fishing. Timeseries analyses showed significant declining trends in local abundances of sailfish in the southern and central Pacific of Costa Rica over the last decade. Bycatch records from the commercial purse seine fleet operating in Costa Rican waters also show a declining trend in sailfish numbers. On the other hand, commercial landings from the national longline fleet show a significant increase of 108%, on average, over the past decade. Different numerical models indicated that fishing pressure from the national fleet and also sea surface temperature with different time lags affect local abundances of sailfish. While other countries in Central and North America protect sailfish and other species of tourist interest, Costa Rica still allows the landing and sales of billfishes as seafood. The results presented in this study highlight the need to allow for the recovery of local abundances of sailfish and promote the development of the coastal communities that depend on marine tourism as their main source of income.

Nocturnal variation of the zooplankton community in coral reef substrates at Isla del Coco National Park (Eastern Tropical Pacific)

Introduction: Zooplankton is a major link in coral reef food webs and a source of nutrients for corals. Demersal zooplankton in coral reefs makes diel migrations at night to avoid predation by fish and corals, increasing abundance and biomass at night. Objectives: To study the composition and variation of the demersal and pelagic zooplankton community at night and to increase the taxonomic knowledge of the benthic copepod fauna over different substrates of a coral reef. Methods: Traps made of plastic, with a 100 μm mesh size collector cup attached, were placed for 12 hours between 5-10 m depth over four substrates: (1) sand, (2) small and (3) big colonies of Porites lobata, and (4) dead and alive corals. Sampling started at dusk (1800 h), and the collector cups were collected and replaced at 2100 and 0000, and the last samples removed at down (0600 h). Results: The highest abundance of zooplankton was capture over P. lobata colonies between 0000 to 0600 h. Copepods (adults, copepodites, and nauplii) dominated the community structure and were more abundant during all the time intervals and substrates. Pelagic copepods were more abundant than the benthic, however, not more diverse. Among the benthic copepods, 20 new records of harpacticoids and calanoids were registered for Isla del Coco and Costa Rican waters. Appendicularians and decapod larvae were also abundant. Changes in coral reef community structure were related with time and not with the kind of substrate, although some taxa were found only in a specific time interval or substrate. Conclusions: Community structure and abundance of demersal and pelagic coral reef zooplankton in Chatham Bay were dominated by copepods, larvaceans and decapod larvae, similar to other coral reefs around the world. The highest abundance peak of organisms in the water column between 0000 to 0600 h could be related to diel migration.

<i>Kappaphycus alvarezii</i> (Rhodophyta): New Record of an Exotic Species for the Caribbean Coast of Costa Rica

Kappaphycus alvarezii, a red macroalgal species native to South-East Asia, has been introduced for commercial purposes to more than 20 tropical countries. In 2000, Panama became the first Central American country to develop its cultivation following a pilot-commercial approach. Twelve years after his introduction to Panama, the species was found to the south Caribbean coast. In the present study, we report the first record of K. alvarezii collected in Costa Rican waters. Genetic identification of the sample was performed with the mitochondrial marker cox2-cox3 intergenic spacer, and phylogenetic analyses showed that the sample collected grouped into a monophyletic clade with GenBank sequences from Vietnam, Indonesia, the Philippines, Brazil and Venezuela. Here we provide further description of its position with respect to other strains of K. alvarezii collected globally. Its possible route of entry to the Caribbean coast of Costa Rica is discussed. To date, it is possible to locate K. alvarezii in different areas away from the production fields which show its dispersion, and that the species is expanding; but more studies are needed to know the phase of colonization in which it is located because it is a combination of natural factors and human exploitation that determines the invasive potential of the species.

Clave dicotómica para la identificación de Apendicularias en el PacíficoTropical Oriental y Mares Interamericanos, con un listado de especies para Costa Rica

Although appendicularians are relevant primary consumers and are part of every zooplankton community, there is a lack of information on the species present in different ocean regions. Thus, regional identification guides are useful to develop datasets with high taxonomic resolution. Appendicularian species were identified in 33 epipelagic samples of zooplankton collected in several locations of Costarican waters. Eighteen appendicularian species were identified, of which 15 were found in the Pacific and only three in the Caribbean. Seven species are new records for Costa Rican Pacific waters (Appendicularia sicula, Fritillaria charybdae, F. cf. pacifica, F. tenella, F. pellucida f. omani, Oikoipleura fusiformis f. cornutogastra and Pelagopleura verticalis). Data for each species distribution in Costa Rica is presented together with a key for the identification of appendicularian species recorded in the Inter-American seas and the Eastern Tropical Pacific.

Chondrichthyan Diversity, Conservation Status, and Management Challenges in Costa Rica

Understanding key aspects of the biology and ecology of chondrichthyan fishes (sharks, rays, and chimaeras), as well as the range of threats affecting their populations is crucial given the rapid rate at which some species are declining. In the Eastern Tropical Pacific (ETP), the lack of knowledge, unreliable (or nonexistent) landing statistics and limited enforcement of existing fisheries regulations has hindered management and conservation efforts for chondrichthyan species. This review evaluated our current understanding of Costa Rican chondrichthyans and their conservation status. Specifically, we (1) provide an updated checklist on the species richness, habitat use and distribution patterns, (2) summarise the most relevant chondrichthyan studies (scientific publications, theses, and official technical reports), (3) identify knowledge gaps, (4) discuss fisheries-related threats, and (5) highlight the management challenges and research needs to effectively protect their populations. A total of 99 chondrichthyan species are formally recorded in Costa Rican waters, from which 15% are threatened with extinction and 41% are “Data Deficient” based on the IUCN (International Union for Conservation of Nature) Red List. A total of 121 studies were published between 1891 and 2017; 82% in the Pacific (24% from Isla del Coco) and only 18% from the Caribbean Sea. These results highlight the need to redirect research efforts on specific taxonomic groups and geographic regions (i.e., Caribbean). Based on our review, improving the quality and quantity of fisheries landing statistics, as well as determining the degree of overlap between chondrichthyans and small-scale coastal/pelagic fisheries remains a priority. We proposed an adaptive management framework for chondrichthyan fisheries in data-poor countries where management goals/targets are clearly defined. This framework could strengthen the conservation of chondrichthyan populations in Costa Rica and the region.

Euphausiids (Crustacea: Euphausiacea) from a hotspot of marine biodiversity, Isla del Coco, Costa Rica, Eastern Tropical Pacific

Euphausiids have been well studied in several regions of the Pacific Ocean; however, there is lessinformation regarding euphausiids in Costa Rican waters. We analyzed euphausiid specimens collected aroundIsla del Coco National Park during 2011 and 2012. A total of 130 specimens were analyzed and 13 euphausiidspecies were identified, belonging to four genera and one family. An annotated list of species is presented,with photographs and details for their identification. All species found represent new records for waters aroundIsla del Coco in the Costa Rican Pacific. The most frequent species were Euphausia diomedeae, Euphausiadistinguenda, Nematoscelis gracilis and Stylocheiron affine. Rev. Biol. Trop. 64 (Suppl. 1): S221-S230. Epub2016 Febrary 01.

Systematic and Ecological Notes on Some Fishes Collected in the Vicinity of Tortuguero, Caribbean Coast of Costa Rica

The fishes listed in this report represent collections made primarily by Ogren and Giovannoli while they were in Costa Rica during the summers of 1956-58 and 1955, respectively, as University of Florida Research A-ssistants engag­ed in a study of the ecology and migrations of sea turtles (National Science Foun­dation Grants G-1684 and G-5479, University of Florida-Principal Investigator, Archie Carr). A few additional specimens, designated in the following annotated list, were taken by others who were at Tortuguero during the months Ogren and Giovannoli were collecting. Since the specimens were taken during only one season of the year, with limited equipment, and only incidental to the turtle work, this list is not intended as a presentation of the entire fish fauna of the area. However, the locality is isolated, and knowledge of some of the fish species augments what is known of the ecology and ranges of fishes known to occur in neighboring or distant countries to the north or south. This is particularly true of the marine species, as practically nothing has been written concerning their actual occurrence in Caribbean Costa Rican waters.

New records of gelatinous zooplankton from an oceanic island in the Eastern Tropical Pacific

Gelatinous zooplankton are an abundant and diverse group of animals in the pelagic environment. However, knowledge of species diversity and spatial distributions, as well as their ecological role, is scarce. We present information of epi- and mesopelagic gelatinous zooplankton recorded by the ‘DeepSee’ submersible between 2006 and 2012 at Isla del Coco (Cocos Island), Costa Rica, an oceanic island in the Eastern Tropical Pacific. Two species of scyphomedusae, three species of hydromedusae, two genera of siphonophores, and two species of ctenophores were observed in the videos, at depths between 50 and 400 m. None of these species had been previously recorded in the waters around the island. Furthermore, except for the jellyfish Pelagia noctiluca and a siphonophore in the genus Praya, all are new records for Costa Rican waters. This study also includes the first record of the cnidarians Modeeria rotunda, Solmissus sp., Halitrephes maasi and Apolemia spp., and the ctenophore Thalassocalyce inconstans in the Eastern Tropical Pacific. We show that surveys in regions with little information about gelatinous zooplankton may broaden our knowledge of their natural history and may result in new records of gelatinous species.

A new <i>Lepeophtheirus</i> (Copepoda: Siphonostomatoida: Caligidae) from Isla del Coco National Park, Costa Rica, Eastern Tropical Pacific

Among the several groups of copepods that are teleost parasites, the siphonostomatoid family Caligidae is by far the most widespread and diverse. With more than 108 nominal species, the caligid genus Lepeophtheirus von Nordmann is one of the most speciose. There are no reports of this genus in Costa Rican waters. A new species of Lepeophtheirus is herein described based on female specimens collected from plankton samples in waters off Bahía Wafer, isla del Coco, an oceanic island in the Eastern Tropical Pacific. The new species, L. alvaroi sp. nov., has some affinities with other congeners bearing a relatively short abdomen, a wider than long genital complex and a 3-segmented exopod of leg 4. it differs from most of these species by the presence of an unbranched maxillular process and by the relative lengths of the terminal claws of leg 4, with two equally long elements. it is most closely related to two other Eastern Pacific species: L. dissimulatus Wilson, 1905 and L. clarionensis Shiino, 1959. it differs from these species by the proportions and shape of the genital complex, the shape of the sternal furca, the relative length of the maxillar segments, the absence of a pectiniform process on the distal maxillar segment, the length of leg 4 and the armature of leg 5. The new species represents the first Lepeophtheirus described from Costa Rican waters of the Pacific. The low diversity of this genus in this tropical region is explained by its tendency to prefer hosts from temperate latitudes. Until further evidence is found, the host of this Lepeophtheirus species remains unknown. Citation: Suárez-Morales, E. & R. Gasca. 2012. A new Lepeophtheirus (Copepoda: Siphonostomatoida: Caligidae) from isla del Coco National Park, Costa Rica, Eastern Tropical Pacific. Rev. Biol. Trop. 60 (Suppl. 3): 235-242. Epub 2012 Dec 01.

Observation frequency and seasonality of marine birds off the Pacific coast of Costa Rica

<p>Although the Eastern Tropical Pacific is well known for its diverse fauna, the seabirds occurring off Costa Rica’s Pacific coast have received little scientific attention. With seabirds now the fastest declining avian group, a better understanding of seabird diversity and abundance in this region is urgently needed. We report on observations of Costa Rica’s Pacific seabirds made during 19 days of observations on 11 offshore trips from 2006-2010. We provide, for the first time, spatially and seasonally explicit information on the distribution of 41 species of seabirds (nine families). Species diversity is higher during the dry-wet season (36 species) and wet-dry season transitions (36 species) than during the dry season (19 species). The fauna included three threatened species (<em>Pterodroma phaeopygia</em>, <em>Procellaria parkinsoni</em>, and <em>Puffinus creatopus</em>) and two near-threatened species (<em>Psueudobulweria rostrata</em> and <em>Thalasseus elegans</em>), highlighting the importance of Costa Rican waters for the conservation of seabirds.</p><div> </div>

Evaluación en el agua para consumo humano de subproductos de cloración y su relación como inductores de mutagénesis (mutaciones celulares)

<p class="Default">En el proceso de cloración del agua se produce una serie de reacciones químicas entre el cloro utilizado en la desinfección y la materia orgánica presente en el agua. La naturaleza y la concentración de los com­puestos formados son dependientes de variables físicoquímicas de la materia orgánica del suelo, las cuales reaccionan con el cloro agregado originán­dose productos que son compuestos de diferente toxicidad, entre ellos los mutagénicos y carcinogéni­cos; a todos ellos en conjunto se les conoce como productos secundarios de cloración (SPD, por sus siglas en inglés), en los que se incluyen los compues­tos llamados trihalometanos (THM). Se investigó la presencia de este tipo de subproductos en aguas costarricenses por medio de la técnica de microex­tracción en fase sólida (HEADSPACE / SPME Solid Phase Microextraction / GS-MS), utilizando un Cromatógrafo de Gases Varian 450 acoplado a un Espectrómetro de Masas.</p> <p class="Pa8">Se analizaron en total 39 muestras, provenientes de fuentes de agua subterránea (nacientes) admi­nistradas por la Municipalidad del Cantón Central de Cartago y agua de origen superficial (plantas de tratamiento completo) dispensada por los sistemas de tratamiento del AyA/Cantón Central de Cartago y los Sistemas de Tratamiento del AyA de Moravia, Guadalupe y Pavas, con un total de 156 subproduc­tos determinados y cuantificados, correspondiendo estos a cloroformo, bromodiclorometano, dibromo­clorometano y tribromoclorometano.</p> <p class="Pa8">En las muestras de agua de los sistemas de tratamien­to completo se encontró que de 80 subproductos analizados, 12 superaron el máximo permitido de acuerdo con el Reglamento Nacional de Calidad de Agua para consumo humano, mientras que de los acueductos abastecidos por medio de aguas subterráneas administrados por la Municipalidad de Cartago, de 76 subproductos analizados solo uno superó el valor máximo permitido.</p>

First record, and range extension, of the Slimy head Hoplostethus mento (Beryciformes: Trachichthyidae) from the Pacific coast of Costa Rica

A specimen of the Slimy head Hoplostethus mento was collected at a depth of 650–700 m from off the Pacific coast of Costa Rica. This specimen constitutes the first record of the species in Costa Rican waters and a north-west range extension of about 600 km on known distribution. A brief description of the specimen as well as comparative morphometric data and distributional information are provided.

Interpopulation Comparison of Reproduction of the Atlantic Shrimp Hippolyte obliquimanus (Caridea: Hippolytidae)

The genus Hippolyte is represented by typically small shrimps with intriguing mechanisms of reproduction. In order to study possible variability in reproductive aspects among different populations, we conducted an exhaustive comparative study of H. obliquimanus from South (Brazil) and Central American (Costa Rica) waters. The study focuses on fecundity and reproductive output. Mean size of ovigerous females was significantly larger, and both mean reproductive output and mean fecundity were significantly higher in specimens from Costa Rica then in those collected in Brazil. Embryo volume was significantly smaller in the Costa Rican population, and in both populations embryos doubled their volume during embryogenesis. We discuss and compare our findings with the information available regarding H. obliquimanus and other hippolytid shrimp. The reproductive traits of both populations of H. obliquimanus show some important differences which may reflect adaptations to local environmental conditions, demonstrating a high plasticity of reproductive features of the species in Brazilian and Costa Rican waters.

Occurrence of the Phoronid Phoronopsis albomaculata in Cocos Island, Costa Rica

The phoronid Phoronopsis albomaculata was collected in subtidal (28–35 m) sandy sediments in Bahia Chatham during a benthic survey designed to describe the biota of Cocos Island (Isla del Coco), Costa Rica, a national park and Human Heritage Site. Occurrence of this widespread species in Cocos Island is the first report of a phoronid for Costa Rican waters and is the second locality recorded for the eastern Pacific. Taxonomically significant characters (presence of an epidermal collar, extent of coiling of lophophore and nephridia) are discussed. Comparisons are made between depth and abundance of this species from Cocos Island and results of previous studies.

Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica

Twenty nine cetacean species occur in Costa Rican waters but extensive research has been conducted only for three species. The latter shows there is a lack of general and local information about these mammals, even when the country, has shown a remarkable growth in whale watching activities. The increasing use of marine resources in coastal areas has also developed the need to determine the occurrence of cetaceans in areas showing high tourist presence, in order to propose sound conservation measures. In this study, environmental variables were determined and subsequently related to the presence of the species recorded, out of 166 sightings, between 2005 and 2006. The species with highest proportion of sightings were Stenella attenuata (68%), followed by Megaptera novaeangliae (13%) and Tursiops truncatus (10%). The presence of spotted dolphins is related to changes in salinity and water transparency, while that of the humpback whale was related to wave height (Beaufort scale) and water temperature. The presence of seven species of cetaceans was confirmed in two coastal areas of the Pacific coast of Costa Rica, from which three are present throughout the year. Environmental variables were found related to the presence of at least two species.

Lack of xenoestrogen-induced vitellogenin in male olive ridley sea turtles (Lepidochelys olivacea) from the Pacific coast of Costa Rica

Olive ridley sea turtles (Lepidochelys olivacea) distribute widely throughout Eastern Pacific (EP) waters. During reproduction these animals aggregate near coastal waters where they may be exposed to industrial or agrochemical environmental pollutants that may disrupt the endocrine system of these reptiles. One group of compounds of concern is the persistent organic pollutants (POPs), some of which have been detected in Costa Rican waters. Some of these POPs, such as polychlorinated biphenyls and DDT and its metabolites, exhibit estrogenic activity in reptiles. It is unknown whether olive ridleys are exposed to endocrine disruptive doses of these POPs throughout their life in EP waters. Consequently, this study was conducted to determine whether there is evidence of exposure of male olive ridleys to estrogenic compounds. During the study a total of 35 males were hand-captured while mating off the coast of Ostional, Costa Rica, a major nesting beach for this species. The captured turtles were brought aboard a small boat, and blood samples taken with a hypodermic syringe. Turtles were carefully released in the water after the blood samples were taken. In the laboratory, blood collected from these males was analyzed by Western blot using an antibody developed against red-eared slider turtle vitellogenin. Vitellogenin is a female-specific protein that is induced by estrogen during gonadal recrudescence. Estrogenic compounds have been shown to induce this protein in reptilian species. Results of this study indicate the lack of evidence of vitellogenin in the blood of olive ridley males as shown by Western blot analysis. This study demonstrates the feasibility of using the slider’s vitellogenin antibody to detect the presence of the protein in the olive ridley sea turtle, L. olivacea. Rev. Biol. Trop. 56 (Suppl. 4): 49-57. Epub 2009 June 30.

Estomatópodos y decápodos (Crustacea), de la expedición RV Urracá-STRI (2005) en las costas del Pacífico central y norte de Costa Rica

Stomatopods and decapods (Crustacea), of the expedition RV Urraca-STRI (2005) on the Pacific coast of central and northern of Costa Rica. During the RV Urraca – STRI (June-July 2005) expedition to the Central and Northern Pacific coast of Costa Rica, 90 species of crustaceans were collected. Seven were identified to family, four to genus and 79 to species. Of the four genera and 79 species (five stomatopods and 74 decapods), 66 have been reported previously for Costa Rican waters, 17 are new samples for the Museo de Zoologia, Universidad de Costa Rica collection, 10 are new records for the country, and three represent range extensions. Rev. Biol. Trop. 56 (Suppl. 4): 105-112. Epub 2009 June 30.

Concentration of statolith trace elements in the jumbo flying squid during El Niño and non-El Niño years in the eastern Pacific

Statoliths of the jumbo flying squid Dosidicus gigas (Cephalopoda: Ommastrephidae) in the eastern Pacific in 1995, 1996 (non-El Niño years) and 1997 (El Niño year) were analysed to observe whether unusual temperature increases due to El Niño was recorded in the concentration of trace elements. In addition to calcium (the major element), trace elements of manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), and strontium (Sr) were detected. Strontium concentration in the calcified tissue of some aquatic animals changes with environmental variables. However, yearly comparisons revealed that Sr concentration did not significantly differ between the El Niño year and non-El Niño years. Instead, the Sr concentration differed with squid habitats. Strontium concentration in statoliths of D. gigas from Peruvian waters (high salinity) was significantly higher than those from Costa Rican waters (low salinity) regardless of El Niño.

The Impact of Commercial Exploitation on Sawfish and Shark Populations in Lake Nicaragua

The Lake Nicaragua Río San Juan System harbors two classical examples of freshwater adaptation by elasmobranchs, the bull shark, Carcharhinus leucas, and the largetooth sawfish, Pristis perotteti. The bull shark is heavily concentrated around the river mouth and reproduces along the coast. The sparser population in the lake is recruited almost entirely through upstream movements from the lower river. Relatively heavy, year round commercial fishing around the river mouth since the late 1960's has sharply reduced the shark population in the lake. Since the shark fishery is primarily in Costa Rican waters, control and management can be effected only by a cooperative agreement between Costa Rica and Nicaragua, which has not yet been reached. The sawfish lives and reproduces primarily in the lake, where until 1970 a heavy concentration occurred, with relatively few being found in the lower river. Since 1970 heavy commercial fishing for sawfish has been carried on in Lake Nicaragua. A sharp reduction in the population became evident within two years. Early and continued warnings were sounded and attempts were made by the Division of Fisheries to control the operation. However, controlling interest in the fishery was held by individuals highly placed in the government. They continued to fish with no regard for the survival of the sawfish, but with the sole purpose of exploiting the resource until it was no longer profitable, and the population in the lake was reduced to a dangerously low level. The Fisheries Institute of the new Nicaraguan government has finally placed in effect a two year moratorium on the fishing of both sharks and sawfish in Lake Nicaragua and has started a program of research and monitoring of the sawfish population to develop a management program. Time will tell if the unique resource of Nicaragua has been saved.