Fish within the family Tetraodontidae are potential sources of both endogenous tetrodotoxins (TTXs) and dietary derived saxitoxins (STXs). Ingestion of fish tissues containing these toxins by other vertebrates can lead to severe illness and death. The Caribbean sharpnose puffer (Canthigaster rostrata) is a widespread tetraodontid species within the western Atlantic. Mass settlement of juveniles into foraging habitats have been associated with large-scale puffer fish mortality events. In 2013, 2014, and 2017, puffer mortality events on the southern Caribbean coast of Costa Rica were also associated with strandings of green turtles (Chelonia mydas) found to have fed on C. rostrata. Stranded sea turtles were found dead without apparent cause or alive with severe neurological signs that resolved during short periods of captivity. Puffer fish and turtle organ samples were analyzed for both TTXs and STXs. Concentrations of TTXs were extremely low in the fish (0.5-0.7 µg/g) and undetectable in turtle stomach contents. However, concentrations of STXs in whole fish (16.6-47.5 µg STX-eq/g) exceeded the 0.8 µg STX-eq/g human seafood safety threshold for STXs by orders of magnitude. Saxitoxins were also detected in samples of stomach contents (ingested fish), brain, lung, kidney, and serum from three affected turtles. Study results indicate that saxitoxicosis resulting from opportunistic foraging on C. rostrata during fish mortality events may be a significant factor in episodic stranding of green sea turtles in this region.

RESUMENEn este estudio se analizaron los eventos de floraciones algales nocivas (FAN) en cuatro estaciones de muestreo fijas en el Golfo de Nicoya durante el periodo de enero de 2008 a diciembre de 2010. Se recolectaron muestras de agua a 1 y 5 m de profundidad durante cada evento de FAN. Además, se midieron in situ los parámetros fisicoquímicos: profundidad del disco de Secchi, temperatura, salinidad, oxígeno disuelto y el porcentaje de saturación de oxígeno del agua. Los datos de radiación solar y precipitación fueron suministrados por el Instituto Meteorológico Nacional de Costa Rica. Se determinaron las concentraciones de las microalgas responsables y las especies asociadas. Se registraron 11 eventos, de los cuales el 72.7% se presentaron en la época lluviosa y un 27.3% en la época seca, la mayoría de éstos, durante el fenómeno atmosférico de La Niña. Las especies responsables fueron los dinoflagelados Alexandrium monilatum, Levanderina fissa, Cochlodinium polykrikoides y Prorocentrum minimum, la diatomea Skeletonema costatum y la cianobacteria Trichodesmium erythraeum. Las especies asociadas que se registraron con mayor frecuencia fueron los dinoflagelados Dinophysis caudata, Prorocentrum micans, Tripos fusus, Tripos furca y Protoperidinium conicum. Las FAN en el Golfo de Nicoya fueron más frecuentes durante la época lluviosa, probablemente debido a los aportes fluviales al sistema estuarino de los ríos Tempisque, Barranca y Grande de Tárcoles. Esa estacionalidad, en conjunto con las alteraciones provocadas por eventos atmosféricos globales como La Niña y El Niño, determinó la formación de FAN en el golfo durante el periodo de estudio.Palabras claves: Floraciones algales nocivas, microalgas responsables, condiciones ambientales, El Niño y La Niña, Golfo de Nicoya. ABSTRACTHarmful Algal Blooms (HABs) events were analyzed in this study at four monitoring stations in the Gulf of Nicoya between January 2008 and December 2010. Water samples were collected at 1 and 5 m deep during each HAB event. Furthermore, the following physicochemical parameters were measured in situ: Secchi disk depth, temperature, salinity, dissolved oxygen, and saturation percentage of oxygen in water. Radiation and precipitation data was provided by the National Meteorological Institute of Costa Rica. The concentration of dominant microalgae and associated species was determined. A total of 11 events were recorded, 72.7% during rainy season and 27.3% during dry season, most of them during the La Niña atmospheric phenomenon. Dominant species included the following dinoflagellates; Alexandrium monilatum, Levanderina

Efectos de El Niño y La

The aim of this study was to evaluate the spontaneous spawning of the first generation of weakfish (Cynoscion squamipinnis) reared in captivity in order to conduct restocking programs and mariculture projects. Juveniles obtained from spontaneous spawning of wild fish caught in the Gulf of Nicoya were reared at the Laboratory of Marine Fish Reproduction and Culture in the Juan Bertoglia Richards Marine Biology Station, Universidad Nacional, Puntarenas, Costa Rica. Fish were kept in 18 t tanks, with constant water exchange (100% per day), at a temperature of 26.73 ± 1.15°C, 32.60 ± 2.69 PSU salinity, and 6.20 ± 0.61 mg/L dissolved oxygen. Every two months croakers were anesthetized and examined for sexual maturity. In January 2011, maturity of one female was confirmed by ovarian biopsies, and oocytes of 0.4-0.6 mm diameter were observed; also fluid semen was obtained from males through abdominal massage. In March 2011, a period of spontaneous spawning began, without any environmental or hormonal stimulation. In total 34 spawns were recorded from March to October 2011, for an average of 85,996 eggs, with a maximum production of 461,000 eggs and a minimum of 4,500 eggs. Fertilization percentage was 10-80%, with an average of 53.09 ± 26.97%. No significant correlations were found between spawns and environmental variables such as temperature, salinity, dissolved oxygen, tides, moon phases and precipitation.

Costa Rica muestra una condición incipiente en el desarrollo de la acuicultura marina, a pesar de los esfuerzos invertidos por más de veinte años. La experiencia en el cultivo de Crassostrea gigas alcanzada por comunidades, la institucionalidad pública y ONG´s, desde el ámbito social- económico y ambiental, evidencian que el país cuenta con las condiciones idóneas, para direccionar la ostricultura como un nuevo sector socio-económico con y desde las comunidades marino costeras del litoral pacífico. El presente trabajo expone los logros obtenidos por comunidades y actores locales; además los retos que ambas partes se han propuesto para hacer de esta actividad una herramienta más que contribuye con la sustentabilidad y empoderamiento de familias y comunidades que actualmente se encuentran en condiciones de pobreza.