Resumen: La extracción activa del erizo de mar Lytechinus variegatus en el noreste de Venezuela podría conllevar a una reducción de su densidad poblacional. Por consiguiente, el conocimiento sobre el crecimiento somático y la producción gonadal es de importancia para la explotación racional y el manejo sustentable de sus poblaciones. Durante un ciclo anual, este estudio examinó la biología reproductiva e índices moleculares de crecimiento (ARN:ADN y Proteína:ADN) de una población del erizo L. variegatus en el Golfo de Cariaco (Venezuela); un ecosistema marino regulado por las temporadas de estratificación y surgencia costera. La población de erizos de mar presentó tallas homogéneas, con incrementos significativos en la masa fresca total (MF) y el índice gonadosomático (IG) durante la estratificación. Se obtuvieron modelos de regresión significativos durante los periodos de surgencia y estratificación, particularmente entre la MF en relación con las dimensiones de la testa y linterna de Aristóteles. El desarrollo gonadal fue continuo, mostrando desoves parciales durante el período de surgencia. El cociente ARN:ADN incrementó durante la temporada de estratificación, no así el cociente Proteína:ADN. El Análisis de Componentes Principales indicó asociación entre los índices moleculares de crecimiento con el seston, contrariamente a la biomasa fitoplanctónica, y la temperatura superficial del agua. El ciclo reproductivo del L. variegatus presentó un patrón estacional asociado a la temperatura y productividad primaria; desova activamente durante la temporada de surgencia, y la gametogénesis se potencia durante la estratificación, cuando son mayores los procesos metabólicos.

Abstract: Active extraction of sea-urchin Lytechinus variegatus from the northeast of Venezuela could cause a reduction in the populational density. Therefore, knowledge about somatic growth and gonadal production is relevant for the rational exploitation and sustainable management of sea-urchin populations. During an annual cycle, this study examined the reproductive biology and growth molecular indices (RNA:DNA and Protein:DNA) of a population of L. variegatus sea-urchin from Cariaco Gulf (Venezuela); a marine ecosystem influenced by the seasons of stratification and coastal upwelling. Sea-urchin population was composed of homogeneous sizes, with significant increase of the total fresh mass (MF) and gonadosomatic index (IG) during stratification. Significant regression models were obtained during upwelling and stratification periods, particularly among the MF with testa dimensions and Aristotle’s lantern. Gonadal development was continuous, showing partial spawning during the upwelling period. RNA:DNA ratio increased during stratification season, but not Protein:DNA index. Principal Component Analysis indicated association among molecular growth indices with seston, conversely to phytoplankton biomass, and seawater surface temperature. Reproductive cycle of L. variegatus presented a seasonal pattern associated with temperature and primary productivity; particularly during upwelling it actively spawns, and the gametogenesis is enhanced during stratification, when the metabolic processes are greater.

Abstract Atlantic pearl oyster Pinctada imbricata is a bivalve with high potential for cultivation in tropical and subtropical environments. In this study, P. imbricata energetic metabolism was analyzed throughout a culture cycle at Gulf of Cariaco, Venezuela. Juvenile individuals (shell length 27.40 ± 2.70 mm) were cultured in a long line at 3 m depth between May-2012 and January-2013. Monthly data of biometric measurements, Fulton index (K) and protein, carbohydrate, and lipid content of the adductor muscle, digestive gland, and mantle were estimated, and were related with environmental variables: temperature, chlorophyll a (Ch a), total particulate matter (TPM), particulate inorganic matter (PIM), particulate organic matter (POM) and upwelling index (UI). Shell length increased steadily reaching 46.23 ± 3.79 mm on the 8th month of culture, while average soft tissue weight increased associated to food availability. Biometric data and biochemical substrates from the muscle, digestive gland and mantle presented significant differences among months. Principal Component Analysis (PCA) showed positive relationships between carbohydrate content and temperature; mantle and digestive gland protein content with TPM, PIM, POM, UI; lipid and protein in muscle with K. Energy allocation was associated with environmental factors, mainly through high food availability given the seasonal upwelling pulses in the area.

Resumen La ostra perlera del Atlántico Pinctada imbricata es un bivalvo con gran potencial de cultivo en ambientes tropicales y subtropicales. En este estudio el metabolismo energético de la ostra perla Pinctada imbricata fue analizado durante un ciclo de cultivo en el Golfo de Cariaco, Venezuela. El cultivo se realizó usando individuos juveniles con una longitud total de la concha de 27,40 ± 2,70 mm. Los ejemplares se cultivaron a 3 m de profundidad en un long-line, entre mayo 2012 y enero 2013. Mensualmente se obtuvieron los datos biométricos, el índice metabólico de Fulton (K), el contenido de proteína, carbohidrato y lípido del músculo aductor, la glándula digestiva y el manto los cuales se relacionaron con las variables ambientales de temperatura, clorofila a, material total en suspensión (TPM), materia inorgánica particulada (PIM), materia orgánica particulada (POM), y el índice de surgencia (UI). La longitud de la concha incrementó progresivamente hasta alcanzar 46,23 ± 3,79 mm en el octavo mes del cultivo, mientras que el incremento del peso promedio de los tejidos blandos estuvo asociado a la disponibilidad de alimento. Los promedios de las variables biométricas y bioquímicas del músculo, glándula digestiva y manto presentaron diferencias significativas entre meses. El análisis de componentes principales (PCA) indicó que hubo relaciones significativas del contenido de carbohidratos con la temperatura; las proteínas del manto y la glándula digestiva con TPM, PIM, POM y UI: del contenido de lípido y la proteína del músculo con K. Los compartimientos de energía se asociaron a factores ambientales, principalmente a la alta disponibilidad de alimento debido a los procesos de surgencia estacional de la localidad.

ABSTRACT Individuals of mussels were collected in ponds from a commercial shrimp farm in the Unare region, Anzoátegui State, Venezuela. Identification was carried out using dichotomous keys and corroborated via analysis of similarities between the sequences of partial mitochondrial DNA of the cytochrome oxidase gene and Mytella strigata (Hanley, 1843) reported in GenBank with 99-100% similarity. Morphological analyses further supported the identification of the specimen. The first report of M. strigata in the Venezuelan Caribbean coast suggests that it could be a transplanted species. Possible negative effects of M. strigata on commercial shrimp production systems are discussed.

RESUMEN Se estudió la influencia de las variables ambientales asociadas con tres profundidades de agua (2, 6 y 10 m) en el crecimiento de la concha, la masa seca de los tejidos blandos (MSTB) y la supervivencia de la ostra alada del Caribe Pteria colymbus (Roding, 1798). La clorofila a (Chl-a), el oxígeno disuelto, la materia orgánica particulada (POM) y la temperatura se estudiaron a cada profundidad. Las ostras se colocaron en 135 cestas de plástico con cinco individuos en cada cesta. Se eligieron tres cestas en cada profundidad a intervalos mensuales para las mediciones de parámetros biométricos, bioincrustaciones y supervivencia. Al final del estudio, la masa seca de los individuos cultivados a 10 m fue significativamente menor (prueba no paramétrica de Kruskal-Wallis KW, P < 0,05), mientras que los valores más altos de MSTB correspondientes a las ostras cultivadas a 2 m de profundidad. El análisis del componente principal mostró una relación inversa (temperatura) y directa (Chl-a y POM) con la varianza observada en el MSTB. Teniendo en cuenta los resultados obtenidos en los rendimientos (crecimiento/supervivencia) de P. colymbus, recomendamos llevar a cabo su cultivo a profundidades de agua entre 2 y 6 m.

ABSTRACT We studied the influence of environmental variables associated with three water depths (2, 6 and 10 m) on shell growth, soft tissues dry mass (STDM) and survival of the Caribbean winged oyster Pteria colymbus (Roding, 1798). chlorophyll-a (Chl-a), dissolved oxygen, particulate organic matter (POM) and temperature were studied at each depth. Oysters were placed in 135 plastic baskets with five individuals in each basket. Three baskets at each depth were chosen at monthly intervals for measurements of biometric parameters, biofouling, and survival. At the end of the study, dry mass of the individuals grown at 10 m was significantly lower (Kruskal-Wallis non-parametric test KW, P < 0.05) with the highest values of STDM corresponding to oysters cultivated at 2 m depth. The principal component analysis showed an inverse (temperature) and direct relationship (Chl-a and POM) with respect to the variance observed in the STDM. Taking into account the results obtained in the yields (growth/survival) of P. colymbus we recommend carrying out their culture at water depths between 2 and 6 m.

ABSTRACT The bivalve Nodipecten subnodosus is one of the largest scallop species and has been selected as an appropriate species for mariculture, adapting the culture technology for production in equatorial waters of the eastern Pacific Ocean. A study of its larval development was performed, comparing standard technology with different treatments in terms of larval density (two and four larvae mL-1), temperature (24, 27, and 29°C), photoperiod limitation (darkness) and antibiotic treatment (Florfenicol 1.2 mg L-1). The juveniles obtained (11 mm) were transplanted to suspended culture in Ayangue Bay, Santa Elena Province, Ecuador. Results show suboptimal larval cultures, probably due to water quality. The only treatment that produced competent larvae for metamorphosis (>50% larvae with eyespot) was the darkness treatment after 18 days when the larvae reached 193.4 ± 15.69 μm in length with 33±1.48% survival. However, growth rate (6.2 μm d-1) was also lower than that reported for the N. subnodosus. Juveniles in intermediate culture showed the highest growth rates so far reported for the species (9.3 mm month-1) and reached 64 mm in eight months. The rapid growth in suspended culture conditions with the estimation of >55% survival, suggest N. subnodosus as an emerging species for the diversification of aquaculture in Ecuador.

ABSTRACT Microalgae diets supplemented with cornstarch at a rate of 0.15% of live weight to the conditioning of broodstock and spat growth of Pacific calico scallop Argopecten ventricosus were tested. To determine reproductive condition at the beginning and end of the experiment, the gonads of adults were analyzed by stereological methods. For juveniles, the weekly percent increase of spat was estimated from spat biomass volume. The microalgae diet of Tisochrysis lutea and Chaetoceros calcitrans, supplemented with cornstarch, substantially improved the reproductive status of the scallop, particularly by increasing the number of individuals in mature and mature-spawning stages with more mature oocytes by the scallop. Spat growth improved >80% in the nursery with the diet supplemented with cornstarch compared with the microalgae diet (T. lutea, C. gracilis, and C. calcitrans). It can be suggested that a small addition of cornstarch to a microalgae diets, boosts growth during nursery procedures and performance of A. ventricosus during the routine conditioning of the broodstock.

The pearl oyster, Pinctada imbricata is an indigenous species that can potentially be used for aquaculture in the Gulf of Cariaco. In this work we examined the monthly gonadal development of a juvenile cohort (27.38 ± 2.70 mm) of the pearl oyster in a hanging culture system. Gonadal development was recorded throughout the study period (April 2012-February 2013), reaching the first maximum sexual maturity within five months of fixation. The females showed a sustained decrease of the gonadal index from December associated to the upwelling period, whereas the males presented oscillations that correspond to partial spawning without completely emptying the gonads. The greater frequency of spawning during upwelling, when there is greater availability of food, suggests that he has an opportunistic reproductive strategy. The sex ratio remained unchanged in the study period with a tendency to have more males (53%) at the beginning of the culture, evidencing that the stage of sexual transition of sex change is experienced by a low proportion of the population. Gametogenic development, in turn, was associated with primary productivity (Chl-a) and the availability of organic particles (organic seston). In culture, the oyster reached a size of 43.85 ± 5.66 mm. The increase in shell size was high during the first five months, stopping associated with a partial spawning with high primary production, from which the increase of the shell decreased in exchange for higher gametes production.

La ostra perla, Pinctada imbricata es una especie autóctona que potencialmente puede ser usada para la acuicultura en el Golfo de Cariaco. Se examinó el desarrollo gonadal mensual de una cohorte de juveniles (27,38 ± 2,70 mm) de la ostra perla en un sistema de cultivo suspendido. El desarrollo gonádico se analizó durante todo el periodo de estudio (abril 2012-febrero 2013), alcanzando el primer máximo de madurez sexual a los cinco meses de la fijación. Las hembras mostraron un descenso sostenido del índice gonadal a partir de diciembre asociado al período de surgencia, mientras que los machos presentaron fluctuaciones que corresponden a desoves parciales sin vaciar completamente las gónadas. La mayor frecuencia de desoves durante la surgencia, cuando existe mayor disponibilidad de alimento sugiere que posee una estrategia reproductiva oportunista. La proporción sexual se mantuvo uniforme en el lapso de estudio con una mayor abundancia de machos (53%) al inicio del cultivo, mostrando que la etapa de transición sexual de cambio de sexo se observó en una baja proporción de la población. Además, el desarrollo gametogénico, estuvo asociado con la productividad primaria (Cl-a) y disponibilidad partículas orgánicas en el medio ambiente (seston orgánico). En cultivo, la ostra alcanzó una talla de 43,85 ± 5,66 mm. El incremento en tamaño de la concha fue mayor durante los primeros cinco meses, deteniéndose en un desove parcial asociado a una alta producción primaria, a partir del cual disminuyó el incremento en el tamaño de la concha, pero aumentó la producción de gametos.

Abstract: The mangrove oyster Crassostrea rhizophorae (Guilding, 1828) is the only native species of oyster marketed in Cuba. However, oyster beds (known locally as “bottom oyster”) were found in the mouth of the Cuyaguateje and Cauto Rivers, with a different morphology and occupying a different habitat with respect to C. rhizophorae. These also contribute to oyster production in Cuba. We addressed studies for phenotypic characterization of both oysters found in 3 areas surrounding these 2 rivers, finding evidence of phenotypic and habitat dichotomies of the bottom oyster from the mangrove oyster. We conclude that Crassostrea virginica (Gmelin, 1791) is the species called “bottom-oyster”. Its average size is 61.1 ± 23.46 mm and reaches a maximum length of 145 mm), which is 65% larger than the mangrove oyster C. rhizophorae (average 37.2 ± 11.95 mm, maximum 87 mm) and has higher meat yield (4.5-10.2% meat of total weight) than populations of the mangrove oyster (3.9 to 7.1%). This study is the first report of C. virginica available as a natural resource for commercial exploitation in Cuba. Its excellent performance recommends it for cultivation in the Greater Antilles.

Resumen: El ostión de mangle Crassostrea rhizophorae (Guilding, 1828) ha sido considerado la única especie de ostión nativo que se comercializa en Cuba. Sin embargo, se han encontrando agregaciones de «ostión de fondo» en las cuencas de los ríos Cuyaguateje y Cauto de Cuba, con morfología y hábitat diferentes a C. rhizophorae, cuya extracción contribuye a la producción ostrícola nacional. El presente estudio tuvo como objetivo la caracterización fenotípica de ambos ostiones en 3 zonas de estas cuencas, mostrando evidencias de dicotomías fenotípicas y de hábitat entre ambos recursos pesqueros, mostrando a Crassostrea virginica (Gmelin, 1791) como la especie denominada «ostión de fondo». Esta mostró una talla (promedio 61.1 ± 23.46 mm, máxima 145 mm) superior al 65% de la del ostión de mangle C. rhizophorae (promedio 37.2 ± 11.95 mm, máxima 87 mm), así como un mayor rendimiento (4.5-10.2% de carne con respecto al peso total) que las poblaciones del ostión de mangle (3.9 a 7.1%). Este estudio registra por primera vez la especie C. virginica como recurso natural en explotación comercial en Cuba y su mayor rendimiento evidencia un potencial como especie cultivable en las Antillas Mayores.

Resumo O objetivo deste estudo foi avaliar o efeito da variabilidade ambiental sobre o crescimento e a sobrevivência de mexilhões subtropicais e tropicais Perna perna e Perna viridis em quatro profundidades de cultivo no Golfo de Cariaco, durante um ciclo anual. Juvenis de P. perna (39,1±1,88 mm em comprimento de concha) e P. viridis (36,7±1,87 mm) foram semeados em cordas de nylon (3/4") e suspensos de uma jangada em 1, 3, 6 e 9 m de profundidade. A cada seis semanas, foram amostradas três repetições de cada espécie em cada profundidade. Os parâmetros de crescimento determinados foram: massa e comprimento de concha, massa seca dos tecidos moles, bem como incrustação (fouling) e as taxas de sobrevivência. Temperatura, transparência, clorofila a, oxigênio, salinidade e matéria orgânica e inorgânica particulada foram registados a cada profundidade de cultura com o objetivo de relacionar crescimento e sobrevivência às alterações ambientais. O crescimento de ambas as espécies foi analisado em relação ao ambiente, especialmente à influência dos alimentos e da temperatura. Um período de estagnação do crescimento de P. perna foi associado à maior temperatura e menor biomassa de fitoplâncton, características da temporada com prevalente estratificação da coluna de água (agosto a novembro de 2007). Em contraste, o crescimento do P. viridis não estagnou, embora tenha sido gradual e relativamente inferior. Ao final, P. perna alcançou taxas de crescimento mais elevadas do que P. viridis. Possíveis estratégias de cultivo para melhorar a produção de ambas as espécies de mexilhão são discutidas.

Abstract This study aims to evaluate the effect of environmental variability on the growth and survival of the subtropical and tropical mussels Perna perna and Perna viridis at four different culture depths in the Gulf of Cariaco during an annual cycle. Juveniles of P. perna (39.1±1.88 mm in shell length) and P. viridis (36.7±1.87 mm) were sown on nylon ropes (3/4") and suspended from a raft at 1, 3, 6 and 9 m depths. Every six weeks, three replicates of each species were sampled (10 individuals per replicate) at each depth. Growth parameters were determined: mass and shell length, dry mass of soft tissues as well as fouling and survival rates. Temperature, transparency, chlorophyll a, oxygen, salinity and particulate organic and inorganic matter were recorded at each culture depth for the purpose of relating growth and survival to environmental change. The results show that the growth of both species was linked to the environment, especially with regard to the influence of the food and temperature. A period of stagnant growth of P. perna was associated with the higher temperature and lower phytoplankton biomass that is characteristic of the season with prevalent water column stratification (August-November 2007). By contrast, the growth of P. viridis did not stagnate, although it was gradual and relatively lower. At the end, P. perna achieved higher growth rates than P. viridis. Possible culture strategies to improve the production of both mussel species are discussed.

ResumenLas técnicas histoquímicas hoy en día permiten seleccionar áreas de tejido y generar información confiable sobre la distribución de reservas energéticas en los moluscos bivalvos durante su ciclo de vida. Mensualmente se examinaron las gónadas y la glándula digestiva (GD) de 15 individuos recolectados entre abril 2012 y febrero 2013 por técnicas histológicas e histoquímicas de microscopia de luz, para relacionar el ciclo gametogénico y la disponibilidad de reservas energéticas con los parámetros ambientales. En el ciclo gametogénico, la proporción mensual de organismos maduros fue mayor en los machos entre agosto (40 %) y noviembre (53 %), mientras que las hembras tienden a presentar un ciclo más corto y sincronizado de liberación de gametos (septiembre 67 % y octubre 60 %). Los períodos intensos de desoves coinciden en ambos sexos (octubre-enero). Entre abril-agosto 2012 y enero-febrero 2013, se observan los valores más altos del IGl (índice de glúcido), mientras que en septiembre disminuyen y alcanzaron valores mínimos entre octubre y diciembre. El IL (índice de lípidos) presentó valores máximos en abril-2012 y febrero-2013, con un valor intermedio en agosto. Los resultados indican que las reservas de la GD presentan un patrón de movilización en relación inversa con la proliferación de los gametos de ambos sexos, vinculado directamente con la disponibilidad de nutrientes como la clorofila a y el seston orgánico.

AbstractHistochemical techniques today allow you to select areas of tissue and generate reliable information on the distribution of energy reserves in bivalve molluscs during their life cycle. The main objective of this study was to describe and relate the gametogenic cycle with the availability of energy reserves and the environmental parameters. For this, we sampled and examined the gonads and digestive glands (DG) of 15 individuals collected monthly during April 2012 and February 2013. We processed and analyzed the samples by standard histological and histochemical light microscopy techniques. Our results showed that for the gametogenic cycle, the monthly proportion of mature organisms was higher for males, between August (40 %) and November (53 %), while the females tend to have a shorter synchronized cycle and release of gametes in September (67 %) and October (60 %). The intense spawning periods in both sexes was the same (October to January). Between the periods April-August 2012 and January-February 2013, we observed the highest values of IGl and glucide index (instead, a decrease was observed in September, reaching minimum values during the period October-December). Besides, the maximum values of IL, lipid index, were observed in April-2012 and February-2013, with an intermediate value in August-2013. The results indicated that the reserves of the GD have a pattern of mobilization inversely related to the proliferation of gametes in both sexes; this was directly linked to the availability of nutrients such as chlorophyll a and the organic seston. Rev. Biol. Trop. 64 (2): 849-858. Epub 2016 June 01.

ABSTRACT. The growth and survival of individuals of the pearl oyster Pinctada imbricata (spats of 16-24 mm antero-posterior shell length) belonging to three different cohorts (CI, CII and CIII) were evaluated in suspended culture at Cariaco Gulf, Venezuela, during three contrasting environmental periods. The cultures were made in pearl nets suspended at 2-3 m from a long line. Cohort CI was cultured from October 2007 to April 2008 (covering the period of stratification and upwelling waters of the area), the CII from June 2008 to February 2009 (dominated by the remission of the coastal upwelling and the start of the same) and the CIII from February 2009 to July 2009 (coastal upwelling period). Monthly determinations included the number of gastropods of the genus Cymatium spp., recruited in the culture baskets, shell length, oyster survival, and mass of the shell, muscle and other tissues, as well as, the fouling mass on the shells. Water temperature was continuously recorded, while salinity, chlorophyll, and dissolved oxygen seston biweekly. Results obtained from the different cohorts studied suggest that the variables that significantly affect growth rates were temperature and food availability, whereas the survival rate was inversely associated with incidence of Cymatium spp. The highest rates of growth and survival were observed in individuals of P. imbricata that were grown in the influenced by coastal upwelling period (CIII). This evidence suggests that at this period characterized by higher availability of phytoplanktonic food and low temperatures is the most suitable for the cultivation of the P. imbricata in the southeastern Caribbean.

RESUMEN. Se evaluó el crecimiento y supervivencia de ejemplares de la ostra perla Pinctada imbricata (semillas de 16-24 mm de longitud antero-posterior de la concha) pertenecientes a tres cohortes (CI, CII y CIII) durante tres períodos ambientales diferentes, en cultivo suspendido en el Golfo de Cariaco, Venezuela. Los cultivos se realizaron en cestas japonesas suspendidas en una línea a 2-3 m de profundidad. La CI fue cultivada de octubre 2007 a abril 2008 (comprende periodos de surgencia y relajación), la CII de junio 2008 a febrero 2009 (dominado por la relajación de la surgencia costera) y la CIII de febrero a julio 2009 (dominado por surgencia costera). Mensualmente se registró el número de gasterópodos del género Cymatium reclutados en las cestas, longitud de la concha, supervivencia de las ostras, masa de la concha, músculo, resto de tejidos y organismos incrustantes (fouling) en las conchas. La temperatura del agua se registró continuamente, mientras que la salinidad, clorofila-a, seston y oxígeno disuelto fue quincenalmente. Los resultados sugieren que las variables que afectaron significativamente la tasa de crecimiento, fueron la temperatura y disponibilidad de alimento, mientras que la disminución de la supervivencia se asoció a la incidencia de Cymatium spp. Las mayores tasas de crecimiento y supervivencia se observaron en los ejemplares cultivados en el periodo de surgencia costera (CIII), caracterizado por alta disponibilidad fitoplanctónica y baja temperatura.

Resumen El ciclo gametogénico y el índice gonadosomático (IG) del erizo negro Echinometra lucunter fue examinado entre junio de 2010 y noviembre de 2011 en el noreste de Venezuela (Isla de Lobos, Península de Araya y Ensenada de Turpialito, Golfo de Cariaco). Las gónadas están integradas por extensos acinos ramificados, recubiertos por tejido conectivo, seguido de una capa delgada de células que se diferencian en fagocitos nutritivos y gametos, los cuales cambian en sus proporciones y tamaños con los estadios de maduración. Generalmente, en ambas localidades se presentaron varios estadios de maduración, con desoves simultáneos. En Isla Lobos predominaron los individuos en estado de reserva con un corto período de madurez sexual, mientras que en la Ensenada de Turpialito predominaron organismos maduros y desovados. El IG sugiere que los desoves están asociados a las precipitaciones estacionales de la región; mostrando una estrategia reproductiva conservadora, acumulando reservas energéticas en el periodo de mayor producción primaria asociada a los periodos de surgencia costera, cuando la energía de los fagocitos nutritivos es transferida a los gametos hasta su maduración y expulsión al medio ambiente. Las características biológicas y reproductivas de los organismos en Turpialito mostraron elevados IG y mayor tejido gonadal para consumo comercial.

Abstract Several species of sea urchins are a potential resource for the production of gonads for consumption in Venezuela. We studied the gametogenic cycle and the gonadosomatic index (GSI) of the rock boring urchin Echinometra lucunter between June 2010 and November 2011 in northeastern Venezuela (Isla Lobos, Península de Araya and Turpialito, Gulf of Cariaco). The gonads are composed of long ramified acini, covered by connective tissue, followed by a thin layer of cells that differentiate into nutritive phagocytes and gametes, which change in their proportion and size with the maturity stage. Generally, several maturity stages were observed in both locations, showing simultaneous spawning. At Isla de Lobos the individuals in reserve stage predominated with a short period of sexual maturity, while mature and spawned individuals predominated in Turpialito. The GSI suggests that the greatest spawning activity is associated to the rainy season; showing a conservative reproductive activity, accruing energetic reserves during the period of higher primary productivity associated to coastal upwelling, when the energy of nutritive phagocytes is transferred to gametes, for gamete development and spawning. The biological and reproductive characteristics of individuals at Turpialito showed higher GSI having more gonadal tissue for commercial consumption. Rev. Biol. Trop. 63 (Suppl. 2): 273-283. Epub 2015 June 01.

Resumen Mensualmente entre junio 2010 y agosto 2011 en la ensenada de Turpialito, Golfo de Cariaco, Venezuela, se recolectaron macroalgas e identificaron, y ejemplares de Echinometra lucunter con diámetro de testa 41.04 ± 6.60 mm para examinar el contenido estomacal y el índice de llenado. Se identificaron 65 especies de macroalgas, pertenecientes a los Phylla Rhodophyta, Heterokontophyta y Chlorophyta. La mayor biomasa anual la presentaron Halimeda opuntia (56.5 g.m-2), Acanthophora spicifera (15.94 g.m-2), Sargassum vulgare (15.28 g.m-2) y Centroceras clavulatum (12.26 g.m-2). Los ítems alimenticios más frecuentes fueron las macroalgas filamentosas: Sphacelaria sp. (546) y Herposiphonia sp. (441) y la foliácea Dictyota sp. (410), y entre los invertebrados esponjas (155), moluscos bivalvos (70) y crustáceos cirrípedos (65). El ID osciló entre 0.8 y 6.0% (2.6 ± 1.21 %), con máximos en diciembre 2010 (6.0 ± 2.21 %), abril (4.3 ± 0.34 %) y junio 2011 (4.0 ± 1.79 %), con oscilaciones mensuales asociadas a los períodos de surgencia y estratificación. El conocimiento de las características principales de la dieta, es necesaria para proponer planes de cultivo y de conservación de la especie.

Abstract Echinometra lucunter is relatively abundant in the Venezuela coast, however no details are known about its diet. We compare the stomach contents and repletion index of E. lucunter with macroalgae available in their environment (June 2010-August) and the nutrient cycle at the Golfo de Cariaco. Seventy-one species of macroalgae were identified: Rhodophyta (45), Heterokontophyta (11) and Chlorophyta (15). The mean testa diameter was 41.04 ± 6.60 mm. The food preferences included filamentous, siphonal and calcaeous macroalgae; main food items were the filamentous macroalgae Sphacelaria sp. and Herposiphonia sp., and foliose Dictyota sp., including invertebrates such as sponges, bivalves and barnacle crustaceans. The repletion index was 0.8 - 6.0 % (2.6 ± 1.21 %), maximum values were associated to primary productivity cycle, i.e. December 2010 (6.0 ± 2.21 %), April (4.3 ± 0.34 %), June 2011 (4.0 ± 1.79 %). Food preferences could be associated to the upwelling season and productivity cycle. Rev. Biol. Trop. 63 (Suppl. 2): 233-242. Epub 2015 June 01.

El efecto de la dosis subletal de cadmio 0,05 mg/L en la ostra perla del Caribe Pinctada imbricata se evaluó en organismos de tres tallas diferentes: juveniles de 10-20 mm, 40-45 y adultos > 75 mm. Los bioensayos estáticos se llevaron a cabo durante 7 días con una renovación del metal en el cuarto día de exposición. Al final del bioensayo, se evaluó la reposición de la concha, masa de tejido, consumo de oxígeno y relación ARN/ADN. No se observaron efectos significativos del cadmio en niveles subletales sobre la masa de tejido, índice de ARN/ ADN y consumo de oxígeno, en cada una de las tallas. No obstante, a esta concentración de cadmio se registró una disminución significativamente en la reposición de la concha en los organismos juveniles. La utilización de reposición de concha en juveniles de P. imbricata es recomendada como indicador biológico para establecer pruebas de toxicidad.

The effect of sublethal doses of cadmium 0.05 mg/L in the Caribbean pearl oyster Pinctada imbricata was evaluated in three different sizes: juveniles 10-20 mm, 40-45, and adults >75 mm. Static bioassays were conducted for 7 days with a renewal of metal on the fourth day of exposure. At the end of the bioassay, the replacement of the shell, mass of tissue, oxygen consumption and RNA/DNA ratio were evaluated. No significant effects of cadmium at sublethal concentration were observed in the tissue mass, RNA/DNA ratio and oxygen consumption in each of the sizes evaluated. However, at this concentration of cadmium a significant decrease was observed in the shell replacement in juveniles. The use of shell replacement of P. imbricata juveniles is recommended as a biological indicator in toxicity testing.