Abstract A total of 381 specimens of the tilapia Oreochromis mossambicus collected monthly from May 2017 to May 2018 in the Laguna de Los Patos, Cumaná, Venezuela, to evaluate reproductive parameters of this non-native species. Significant differences were found in relation to average height and weight between males and females, with the highest values in males. The sex ratio was 1:1.5 (males:females), which deviates significantly from the expected 1:1 ratio. The mean length of sexual maturity (Lm50) was 18.0 cm in females and 20.1 cm in males, reflecting that females mature at smaller sizes than males. The monthly variations of the gonadosomatic index (GSI) and the stages of sexual maturity show two reproductive peaks during the study, in October 2017 and April 2018, coinciding with the rainy and dry seasons in the region respectively. The condition factor (CF) showed significant differences between months, but not between sexes, with an average of 1.87 in females and 1.84 in males. The average absolute fecundity was 921 ± 604.6 eggs per fish, with a relative fecundity of 8.36 ± 3.09 eggs per gram of fish. Differences in oocyte size in mature females confirm that the species can spawn repeatedly over a period, which is considered an important factor for the establishment of tilapia in non-native environments. 38 201 Patos Cumaná Venezuela nonnative non native 11.5 115 1 1.5 5 1:1. malesfemales, malesfemales , (males:females) 11 1: Lm50 Lm (Lm50 180 18 0 18. 20 20. GSI (GSI study respectively CF (CF months sexes 187 87 1.8 184 84 92 6046 604 6 604. fish 836 8 36 8.3 309 3 09 3.0 period environments 11. 15 1. (males:females Lm5 (Lm5 2 9 60 83 8. 30 3. (Lm

Resumo Um total de 381 espécimes da tilápia Oreochromis mossambicus foram coletados mensalmente de maio de 2017 a maio de 2018, na Laguna de Los Patos, Cumaná, Venezuela, para avaliar parâmetros reprodutivos desta espécie não nativa. Foram encontradas diferenças significativas em relação às médias de altura e peso entre machos e fêmeas, sendo os maiores valores no sexo masculino. A razão sexual foi de 1:1,5 (machos:fêmeas), o que se desvia significativamente da proporção esperada de 1:1. O comprimento médio de maturação sexual (Lm50) foi de 18,0 cm nas fêmeas e 20,1 cm nos machos, refletindo que as fêmeas amadurecem em tamanhos menores que os machos. As variações mensais do índice gonadossomático (IGS) e dos estágios de maturidade sexual mostram dois picos reprodutivos durante o estudo, em outubro de 2017 e abril de 2018, coincidindo com as estações chuvosa e seca na região, respectivamente. O fator de condição (FC) apresentou diferenças significativas entre os meses, mas não entre os sexos, com média de 1,87 no sexo feminino e 1,84 no masculino. A fecundidade absoluta média foi de 921 ± 604,6 ovos por peixe, com fecundidade relativa de 8,36 ± 3,09 ovos por grama de peixe. Diferenças no tamanho dos ovócitos em fêmeas maduras confirmam que a espécie pode desovar repetidamente ao longo de um período, o que é considerado um fator importante para o estabelecimento de tilápias em ambientes não nativos. 38 201 2018 Patos Cumaná Venezuela nativa masculino 11,5 115 1 1,5 5 1:1, machosfêmeas, machosfêmeas , (machos:fêmeas) 11. 11 1. 1:1 Lm50 Lm (Lm50 180 18 0 18, 20 20, IGS (IGS estudo região respectivamente FC (FC meses sexos 187 87 1,8 184 84 92 6046 604 6 604, peixe 836 8 36 8,3 309 3 09 3,0 período nativos 11, 15 1, (machos:fêmeas 1: Lm5 (Lm5 2 9 60 83 8, 30 3, (Lm

We evaluated the growth and survival of the mangrove oyster Crassostrea rhizophorae (30 mm maximum length) reared in two suspended-culture systems (raft and long-line) using three types of enclosures (oyster enclosures, lantern nets and enclosures based on crates used to transport fish), at a density of 750 ind m-2, in La Restinga Lagoon, Margarita Island, Venezuela, over the course of six months. No significant differences were found in shell growth (length and mass) due to the system and enclosures used; however, raft-cultured oysters showed better tissue growth. At the end of the study, the oysters in lantern nets suspended from rafts obtained a tissue mass that was around 40% higher than that of the rest of the oysters cultured in the other enclosures. Significant differences in oyster survival were not observed for the raft and long-line systems used, but the cumulative survival at the end of the study was significantly higher for the oyster enclosures (52-56%) than for the lantern nets (36-39%) and fish crates (24-25%). We therefore recommend employing rafts and discarding the use of crate-type enclosures in the culture of C. rhizophorae in lagoon systems.

Se evaluó el crecimiento y la supervivencia de la ostra de mangle Crassostrea rhizophorae (30 mm de longitud máxima) bajo cultivo en dos sistemas de flotación (balsa o batea y long line o línea madre) y tres tipos de cestos (cestos ostrícolas, linternas y canastas utilizadas para el trasporte de pescado), a una densidad de 750 ind m-2 en la Laguna La Restinga, Isla Margarita, Venezuela, durante seis meses. No existieron diferencias significativas en el crecimiento de la concha (longitud y masa) debido al sistema de cultivo o las cestos; sin embargo, las ostras cultivadas en el sistema de balsa mostraron mayor crecimiento del tejido, siendo las linternas donde los organismos alcanzaron mayor tejido al final del estudio, en un orden del 40% más alto que las ostras mantenidas en long line. En cuanto a la supervivencia las ostras no mostraron diferencias significativas en los sistemas utilizados, pero sí en las cestos, donde al final del estudio, la supervivencia acumulativa en las cestos ostrícolas, suspendidos en el long line o en las balsas (52-56%) fue significativamente superior a la de las linternas (36-39%) y éstas a las de canastas de pescado (24-25%). Se sugiere la utilización de balsas descartando el uso de cestos para el trasporte de pescado para el cultivo suspendido de C. rhizophorae en sistemas lagunares.

Se evaluó la abundancia de juveniles de Pinna carnea, el crecimiento y su relación con factores ambientales en cultivo suspendido en Turpialito, Golfo de Cariaco, Venezuela. La abundancia se determinó usando colectores suspendidos a 8 m de profundidad en "long line" durante 16 meses. El crecimiento se determinó en cestas de cultivo en un "long line" a 8 m de profundidad y la temperatura y disponibilidad de alimento fueron registrados durante 15 meses. Todos los componentes del cuerpo se incrementaron rápidamente durante los primeros cuatro-cinco meses, posteriormente la masa de todos los tejidos somáticos muestran disminución y gran variabilidad en el crecimiento, coincidiendo con el primer período de desove, lo cual sugiere una influencia negativa de la gametogénesis en el crecimiento somático. Un análisis de regresión múltiple indicó una alta relación del crecimiento y la disponibilidad de alimento. Aunque se determinó una adecuada abundancia de juveniles (máximo 80 por colector-30x60 cm), la recolecta no fue continua. Esta característica, junto con la alta variabilidad del crecimiento y la influencia negativa de los factores ambientales en períodos desfavorables, además de la obtención de músculos de talla comercial en 14 meses, sugieren que la especie no es apropiada para la producción de músculos. Sin embargo, la elevada masa total de sus tejidos comestibles (21 g) y la alta sobrevivencia (96%), sugieren a P. carnea para ser cultivada.

We quantified the abundance of juvenile Pinna carnea at Turpialito, Golfo de Cariaco, Venezuela, using collectors suspended at 8 m depth for 16 months and then evaluated their subsequent growth in suspended enclosures over 14 months in relation to concurrent measures of temperature and planktontonic food availability. All body components showed a rapid increase during the first four-five months. There was a decrease in somatic tissue mass and great variability in growth coincident at first spawning, suggesting a negative effect of gonadal production on somatic growth. A multiple regression analysis indicated a strong relationship between tissue growth and food availability as measured by organic sestonic matter. Although we determinated an adequated spat abundance for culture activities (80 spat per collector-30x60 cm), spat collection was limited, mainly from February through April. In addition to high variability in growth and negative influence of environmental factors during unfavorable periods, the muscles production required in 14 months, suggesting that P. carnea is not appropriate for commercial production of muscle. However, the high weight of all edible tissues mass attained (21 g) and the high survival rate in all experimentation (96%) suggests thatP. carnea is fit for aquaculture.