Cesar Jorge Miguel Lodeiros Seijo (original) (raw)
Papers by Cesar Jorge Miguel Lodeiros Seijo
The immune and antioxidant enzyme defenses in pearl oyster Pinctada imbricata were evaluated afte... more The immune and antioxidant enzyme defenses in pearl oyster Pinctada imbricata were evaluated after shot-term (7d) exposure to 25 and 100% water-soluble fraction (WSF) of Fuel Oil Nº6, a source of polyaromatic hydrocarbon and heavy metal contamination of marine ecosystems. Lysozyme activity in the digestive gland and the phagocytic activity of hemocytes were measured as humoral and cellular immunological responses, respectively, using heat killed yeast cells as antigen for the phagocytosis assay. The viability and total number of hemocytes were recorded. The detoxifying enzymes Glutathione-Stransferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) were evaluated from the digestive gland and mantle extracts. In the digestive gland the exposure to WSF treatments resulted in significant increases of GST and CAT. In the mantle, both experimental treatments increased GPx and decreased GST activity, while CAT was not affected. Immunological indicators w...
La Técnica: Revista de las Agrociencias. ISSN 2477-8982
La moringa (Moringa oleifera L.) es una especie arbórea originaria de la India, adaptable a diver... more La moringa (Moringa oleifera L.) es una especie arbórea originaria de la India, adaptable a diversos climas. Esta especie otorga beneficios para la salud humana por ser fuente de vitaminas, minerales y ácidos grasos polinsaturados, aunque su uso acuícola es escaso. En esta investigación se analizó el perfil lipídico y aminoacídico de harina de hojas deshidratadas de moringa, como un insumo viable y de calidad para la acuicultura de moluscos. Los resultados revelaron en el perfil lipídico la presencia de ácido α-linolénico 13,9 mg/g (ω-3) de la materia seca y también en menor grado, ácido linoléico con 3,13 mg/g (ω-6); el ácido α- linolénico es precursor en vía metabólica del ácido eicosapentaenoico (EPA) y ácido docosahexaenoico (DHA) con funciones biorreguladoras y el ácido linoléico cumple funciones estructurales en las membranas celulares, siendo considerados insumos esenciales para la nutrición inicial en moluscos. El contenido proteico analizado fue de 29,5% con un total de 17 ...
Interciencia, Dec 1, 2018
RESUMEN Las especies de Spondylus constituyen un grupo de moluscos de gran importancia dentro de ... more RESUMEN Las especies de Spondylus constituyen un grupo de moluscos de gran importancia dentro de las culturas americanas desde el tercer milenio a.C. hasta el siglo XVII, recuperando su im-portancia en las décadas recientes. El presente artículo es una cronología sintética del simbolismo del Spondylus en diferentes culturas del pasado de Suramérica. Mediante la reconstrucción histórica del uso del Spondylus se expone el papel que ha juga-do en la historia suramericana, lo cual ha permitido y poten-ciado la interacción entre diferentes culturas. Hoy en día, so-bre todo en Ecuador, ha resurgido el Spondylus como símbolo de gran importancia, suponiendo un vínculo entre regiones y, uniendo las comunidades actuales con su pasado histórico.
La Técnica: Revista de las Agrociencias. ISSN 2477-8982, 2020
Effect of LED and fluorescent lights on growth and biomass of Thalassiosira pseudonana (Cleve, 18... more Effect of LED and fluorescent lights on growth and biomass of Thalassiosira pseudonana (Cleve, 1873) Resumen En búsqueda de mejorar la producción de la microalga Thalassiosira pseudonana, utilizada frecuentemente como alimento para larvas y juveniles de diversas especies de interés acuícola, en este estudio se evaluó la incidencia de diodos emisores de luz (LED) y luces fluorescentes (F) en su crecimiento y biomasa celular. Seis repeticiones de la cepa T. pseudonona, preparada en agua de mar filtrada tratada con UV y medio nutritivo Guillard F2 enriquecido con Na2SiO3, fueron sometidas a 4200 lux (± 5%) emitida desde luces LED y F. Se partió de inóculos en tubos de ensayo de 20 mL y trasvasados a recipientes de mayor volumen cada 3 días, hasta alcanzar 15 L en bolsas plásticas a los 14 días. Al término del ensayo, se determinó la densidad de microalgas, su biomasa y masa celular. El crecimiento fue descrito mediante un modelo exponencial sin diferencia en las tasas de crecimiento en...
Revista De Biologia Tropical, 2016
Several species of sea urchins are a potential resource for the production of gonads for consumpt... more 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, Peninsula 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, ac...
To evaluate the water quality along the continental shoresof Venezuela, where fishing communities... more To evaluate the water quality along the continental shoresof Venezuela, where fishing communities exploit the clam Tivelamactroides, the concentration of heavy metals (Cu, Mn, Fe, Zn,Cd, Ni, Pb y Cr) was determined in superficial sediments,together with environmental factors (temperature, salinity,dissolved O2, pH, phytoplanctonic biomass, seston, and total Nand P) of the litoral waters of Playa Güiria on the northeasterncoast (Sucre State), and of Río Chico and Boca de Paparo (MirandaState), two localities on the central coast separated bysome 5km and influenced by the Tuy River. In Río Chico, andmainly in Boca de Paparo, the concentration of heavy metals inthe sediments (>18μg·g-1 Cu, >3μg·g-1 Cd, >5μg·g-1 Cr, >0.9μg·g-1Pb, >11μg·g-1 Ni) and the environmental factors (>28ºC,<5.6ml·l-1 dissolved O2, >55μmol·l-1 total N, >17μmol·l-1 total P)indicated the presence of polluted systems. This environmentaldamage was linked to the influence of the Tuy River, wh...
Revista de Biología Tropical, 2017
The sea urchins Arbacia incisa and Eucidaris thouarsii (Echinodermata) as fouling biocontrol agen... more The sea urchins Arbacia incisa and Eucidaris thouarsii (Echinodermata) as fouling biocontrol agents in culture cages of Crassostrea gigas (Mollusca: Ostreidae).Fouling clogs cultivation cages of bivalves afecting their growth. We tested biocontrol with sea urchins in the suspended culture of C. gigas during one month. The experimental design included: 1) oysters without sea urchins, 2) oysters with the black sea urchin Arbacia incisa (50.5 ± 0.43 mm of diameter testa-DT), 3) oysters with the pencil sea urchin E. thouarsii (34. 2 ± 2.13 mm DT) and 4) oysters without sea urchins with a pearl net protective bag (to avoid predation). The dry mass of the pearl nets and the oyster soft tissues were determined at the beginning and end of the experiment. There was similar fouling in cages without urchins (55.3 ± 5.80 g) and with A. incisa (46.1 ± 2.84 g). These amounts were significantly higher than those found in cages with E. thouarsii (39.1 ± 1.9 g) and with protective sacs without urchi...
Ciencias Marinas, 2005
We evaluated the growth and influence of environmental factors under suspended culture conditions... more We evaluated the growth and influence of environmental factors under suspended culture conditions of the mussels Perna perna L. and P. viridis L. and of an undefined variant or morphotype sharing the substrate and morphological and colorcharacteristics of both species. The animals were grown for ten months at Turpialito Bay, located in the Gulf of Cariaco, Venezuela. The three experimental populations, seeded with an initial homogeneous size (45–50 mm), showed a similar growth pattern; however, P. viridis showed significantly smaller growth rates than those of P. perna and the morphotype, with a final dorsoventral shell length of 71.2, 77.0 and 77.8 mm, respectively. Correlativity analyses of environmental and growth factors could not define the somatic growth modulation due to environmental factors, but reproductive activity, particularly when it begins for the first time, may act as a negative endogenous factor. Although the results show similar physiological responses fromthe mus...
Brazilian Journal of Oceanography, 2016
This study aims to evaluate the effect of environmental variability on the growth and survival of... more 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...
Revista De Biologia Tropical, Dec 1, 2000
The effect of culture density on growth and survival of juveniles was studied in the scallop Lyro... more The effect of culture density on growth and survival of juveniles was studied in the scallop Lyropecten nodosus with intermediate hanging cultures in Golfo de Cariaco, Sucre state, Venezuela, from December 1993 to July 1994. Six spat-densities (7, 15, 30, 60, 125 and 250 scallops/nets) were evaluated. The initial shell height and dry mass tissue were 9.4 +/- 0.18 mm and 0.007 +/- 0.0026 g, respectively. The specimens were placed into pearl nets and suspended in a long line at 8 m depth. Growth patterns of somatic tissue were similar, but with different magnitudes and inverse proportionality to culture density. No effect of density was observed on survival. These results suggest that intraspecific competition of cultivated scallops cause stress, which affects growth but not survival. We suggest as strategy for the management of culture density, successive density reductions, to obtain in a six months culture (intermediate culture) specimens of 50 mm in shell height in order to start the final culture period.
Revista de Biología Tropical, 2016
Histochemistry of the digestive gland of the pearl oyster Pinctada imbricata (Pterioida: Pteriida... more Histochemistry of the digestive gland of the pearl oyster Pinctada imbricata (Pterioida: Pteriidae) during the gametogenic cycle, Venezuela. Histochemical 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.
Boletin Del Centro De Investigaciones Biologicas, 2007
Se evaluo el efecto del petroleo crudo sobre el crecimiento y la concentracion de clorofila a en ... more Se evaluo el efecto del petroleo crudo sobre el crecimiento y la concentracion de clorofila a en las microalgas del nororiente de Venezuela Tetraselmis sp. (G1), Chaetoceros sp. (A1) y Dunaliella salina (C1), cultivadas en sistemas discontinuos bajo condiciones controladas de temperatura (25 ± 1 °C), iluminacion (39,0625 μEm2/s, fotoperiodo 12:12) y salinidad (37 UPS). Los cultivos fueron expuestos por 96 h a diferentes concentraciones (0, 10, 25 y 50 %) de una fraccion acuosa de petroleo durante las diferentes fases de crecimiento microalgal. El crecimiento fue evaluado a las 6, 12, 24, 48 y 96 h mediante el recuento celular y contenido de clorofila a al inicio, 48 y 96 h. La fraccion acuosa del petroleo influyo sobre el crecimiento y la concentracion de clorofila a, produciendose una disminucion significativa y proporcional al incremento de la concentracion del contaminante. Los mayores efectos se evidenciaron a partir de la concentracion de 25%, generalmente a las 6 h, mostrando que Chaetoceros sp. (A1) posee mayor sensibilidad en la fase logaritmica inicial y Dunaliella salina (C1) en la fase estacionaria. Chaetoceros sp. (A1) fue la microalga que presento los valores mayores de clorofila a, a las 96 h, en las tres fases de crecimiento, estableciendose su maximo en la fase estacionaria (3,4 ± 0,31 pg/cel al 10%), mientras que Dunaliella salina (C1) mostro los valores menores de 0,30 ± 0,13 pg/cel al 50 % del contaminante a las 96 h en fase estacionaria. El crecimiento y el contenido de clorofila a de las microalgas evidencian la sensibilidad al petroleo, lo cual sugiere recomendarlas para analisis ecotoxicologicos de corta duracion.
Revista Colombiana De Biotecnologia, Jun 1, 2013
Crecimiento y composición bioquímica de Limnothrix sp. a diferentes salinidades y concentraciones... more Crecimiento y composición bioquímica de Limnothrix sp. a diferentes salinidades y concentraciones de nitrato Growth and biochemical composition of Limnothrix sp. at different salinities and concentrations of nitrate
Ciencias Marinas
How to cite Complete issue More information about this article Journal's homepage in redalyc.org ... more How to cite Complete issue More information about this article Journal's homepage in redalyc.org Scientific Information System Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Non-profit academic project, developed under the open access initiative
Zootecnia Tropical
We evaluated the energy substrates contained in the gonads of a population of brown mussel Perna ... more We evaluated the energy substrates contained in the gonads of a population of brown mussel Perna perna, located of the Caribbean Sea (Northeastern Venezuela). Specimens were collected monthly, by free diving and autonomous, February 2000-January 2001. To this end, 675 organizations were selected, taking into account sex and reproductive stage. In both sexes, but especially in females, was observed the occurrence of stages of maturity and spawning throughout the year, thus suggesting a continuous playback. As for the falls seen in the dry weight of the gonadal lobes, these corresponded to a temporary basis (April to May
Revista de biología tropical, 2005
We evaluated the biological feasibility of massive larvae and postlarvae production of the Caribb... more We evaluated the biological feasibility of massive larvae and postlarvae production of the Caribbean green-white urchin Lytechinus variegatus. Experiments were designed to choose the initial larval density and microalgae diets under culture, to study metamorphosis, postlarval and juvenile growth. Massive production of competent larvae 650 microm long at 12-13 days is possible using larval densities of 0.25 to 1 larva/ml. The microalgae Rhodomonas sp. was suitable for the optimization of larval growth and survival. Metamorphosis of 100% of the larvae can be induced with films of bentic diatoms (Navicula sp. and Amphora sp.), after 96 h; however, diatoms are not adequate for postlarval development and a food supply of Ulva lactuta is necessary for proper growth. For juveniles, a diet of macroalgae (U. lactuta) and/or commercial marine shrimp culture pellet food is enough for growth, but the best results were obtained with shrimp or U. lactuta used alone (85-86%, against 46% with the m...
The effect of density on growth and secondary production of Euvola ziczac was studied under suspe... more The effect of density on growth and secondary production of Euvola ziczac was studied under suspended culture conditions from June 1988 to January 1989. Seven different densities were ex- amined, using juveniles from 9.6 k 0.3 mm long and 5.17 f 0.6 mg dry weight, which were previously cultivated under hatchery conditions. The growth rate in size and biomass was
The immune and antioxidant enzyme defenses in pearl oyster Pinctada imbricata were evaluated afte... more The immune and antioxidant enzyme defenses in pearl oyster Pinctada imbricata were evaluated after shot-term (7d) exposure to 25 and 100% water-soluble fraction (WSF) of Fuel Oil Nº6, a source of polyaromatic hydrocarbon and heavy metal contamination of marine ecosystems. Lysozyme activity in the digestive gland and the phagocytic activity of hemocytes were measured as humoral and cellular immunological responses, respectively, using heat killed yeast cells as antigen for the phagocytosis assay. The viability and total number of hemocytes were recorded. The detoxifying enzymes Glutathione-Stransferase (GST), glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) were evaluated from the digestive gland and mantle extracts. In the digestive gland the exposure to WSF treatments resulted in significant increases of GST and CAT. In the mantle, both experimental treatments increased GPx and decreased GST activity, while CAT was not affected. Immunological indicators w...
La Técnica: Revista de las Agrociencias. ISSN 2477-8982
La moringa (Moringa oleifera L.) es una especie arbórea originaria de la India, adaptable a diver... more La moringa (Moringa oleifera L.) es una especie arbórea originaria de la India, adaptable a diversos climas. Esta especie otorga beneficios para la salud humana por ser fuente de vitaminas, minerales y ácidos grasos polinsaturados, aunque su uso acuícola es escaso. En esta investigación se analizó el perfil lipídico y aminoacídico de harina de hojas deshidratadas de moringa, como un insumo viable y de calidad para la acuicultura de moluscos. Los resultados revelaron en el perfil lipídico la presencia de ácido α-linolénico 13,9 mg/g (ω-3) de la materia seca y también en menor grado, ácido linoléico con 3,13 mg/g (ω-6); el ácido α- linolénico es precursor en vía metabólica del ácido eicosapentaenoico (EPA) y ácido docosahexaenoico (DHA) con funciones biorreguladoras y el ácido linoléico cumple funciones estructurales en las membranas celulares, siendo considerados insumos esenciales para la nutrición inicial en moluscos. El contenido proteico analizado fue de 29,5% con un total de 17 ...
Interciencia, Dec 1, 2018
RESUMEN Las especies de Spondylus constituyen un grupo de moluscos de gran importancia dentro de ... more RESUMEN Las especies de Spondylus constituyen un grupo de moluscos de gran importancia dentro de las culturas americanas desde el tercer milenio a.C. hasta el siglo XVII, recuperando su im-portancia en las décadas recientes. El presente artículo es una cronología sintética del simbolismo del Spondylus en diferentes culturas del pasado de Suramérica. Mediante la reconstrucción histórica del uso del Spondylus se expone el papel que ha juga-do en la historia suramericana, lo cual ha permitido y poten-ciado la interacción entre diferentes culturas. Hoy en día, so-bre todo en Ecuador, ha resurgido el Spondylus como símbolo de gran importancia, suponiendo un vínculo entre regiones y, uniendo las comunidades actuales con su pasado histórico.
La Técnica: Revista de las Agrociencias. ISSN 2477-8982, 2020
Effect of LED and fluorescent lights on growth and biomass of Thalassiosira pseudonana (Cleve, 18... more Effect of LED and fluorescent lights on growth and biomass of Thalassiosira pseudonana (Cleve, 1873) Resumen En búsqueda de mejorar la producción de la microalga Thalassiosira pseudonana, utilizada frecuentemente como alimento para larvas y juveniles de diversas especies de interés acuícola, en este estudio se evaluó la incidencia de diodos emisores de luz (LED) y luces fluorescentes (F) en su crecimiento y biomasa celular. Seis repeticiones de la cepa T. pseudonona, preparada en agua de mar filtrada tratada con UV y medio nutritivo Guillard F2 enriquecido con Na2SiO3, fueron sometidas a 4200 lux (± 5%) emitida desde luces LED y F. Se partió de inóculos en tubos de ensayo de 20 mL y trasvasados a recipientes de mayor volumen cada 3 días, hasta alcanzar 15 L en bolsas plásticas a los 14 días. Al término del ensayo, se determinó la densidad de microalgas, su biomasa y masa celular. El crecimiento fue descrito mediante un modelo exponencial sin diferencia en las tasas de crecimiento en...
Revista De Biologia Tropical, 2016
Several species of sea urchins are a potential resource for the production of gonads for consumpt... more 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, Peninsula 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, ac...
To evaluate the water quality along the continental shoresof Venezuela, where fishing communities... more To evaluate the water quality along the continental shoresof Venezuela, where fishing communities exploit the clam Tivelamactroides, the concentration of heavy metals (Cu, Mn, Fe, Zn,Cd, Ni, Pb y Cr) was determined in superficial sediments,together with environmental factors (temperature, salinity,dissolved O2, pH, phytoplanctonic biomass, seston, and total Nand P) of the litoral waters of Playa Güiria on the northeasterncoast (Sucre State), and of Río Chico and Boca de Paparo (MirandaState), two localities on the central coast separated bysome 5km and influenced by the Tuy River. In Río Chico, andmainly in Boca de Paparo, the concentration of heavy metals inthe sediments (>18μg·g-1 Cu, >3μg·g-1 Cd, >5μg·g-1 Cr, >0.9μg·g-1Pb, >11μg·g-1 Ni) and the environmental factors (>28ºC,<5.6ml·l-1 dissolved O2, >55μmol·l-1 total N, >17μmol·l-1 total P)indicated the presence of polluted systems. This environmentaldamage was linked to the influence of the Tuy River, wh...
Revista de Biología Tropical, 2017
The sea urchins Arbacia incisa and Eucidaris thouarsii (Echinodermata) as fouling biocontrol agen... more The sea urchins Arbacia incisa and Eucidaris thouarsii (Echinodermata) as fouling biocontrol agents in culture cages of Crassostrea gigas (Mollusca: Ostreidae).Fouling clogs cultivation cages of bivalves afecting their growth. We tested biocontrol with sea urchins in the suspended culture of C. gigas during one month. The experimental design included: 1) oysters without sea urchins, 2) oysters with the black sea urchin Arbacia incisa (50.5 ± 0.43 mm of diameter testa-DT), 3) oysters with the pencil sea urchin E. thouarsii (34. 2 ± 2.13 mm DT) and 4) oysters without sea urchins with a pearl net protective bag (to avoid predation). The dry mass of the pearl nets and the oyster soft tissues were determined at the beginning and end of the experiment. There was similar fouling in cages without urchins (55.3 ± 5.80 g) and with A. incisa (46.1 ± 2.84 g). These amounts were significantly higher than those found in cages with E. thouarsii (39.1 ± 1.9 g) and with protective sacs without urchi...
Ciencias Marinas, 2005
We evaluated the growth and influence of environmental factors under suspended culture conditions... more We evaluated the growth and influence of environmental factors under suspended culture conditions of the mussels Perna perna L. and P. viridis L. and of an undefined variant or morphotype sharing the substrate and morphological and colorcharacteristics of both species. The animals were grown for ten months at Turpialito Bay, located in the Gulf of Cariaco, Venezuela. The three experimental populations, seeded with an initial homogeneous size (45–50 mm), showed a similar growth pattern; however, P. viridis showed significantly smaller growth rates than those of P. perna and the morphotype, with a final dorsoventral shell length of 71.2, 77.0 and 77.8 mm, respectively. Correlativity analyses of environmental and growth factors could not define the somatic growth modulation due to environmental factors, but reproductive activity, particularly when it begins for the first time, may act as a negative endogenous factor. Although the results show similar physiological responses fromthe mus...
Brazilian Journal of Oceanography, 2016
This study aims to evaluate the effect of environmental variability on the growth and survival of... more 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...
Revista De Biologia Tropical, Dec 1, 2000
The effect of culture density on growth and survival of juveniles was studied in the scallop Lyro... more The effect of culture density on growth and survival of juveniles was studied in the scallop Lyropecten nodosus with intermediate hanging cultures in Golfo de Cariaco, Sucre state, Venezuela, from December 1993 to July 1994. Six spat-densities (7, 15, 30, 60, 125 and 250 scallops/nets) were evaluated. The initial shell height and dry mass tissue were 9.4 +/- 0.18 mm and 0.007 +/- 0.0026 g, respectively. The specimens were placed into pearl nets and suspended in a long line at 8 m depth. Growth patterns of somatic tissue were similar, but with different magnitudes and inverse proportionality to culture density. No effect of density was observed on survival. These results suggest that intraspecific competition of cultivated scallops cause stress, which affects growth but not survival. We suggest as strategy for the management of culture density, successive density reductions, to obtain in a six months culture (intermediate culture) specimens of 50 mm in shell height in order to start the final culture period.
Revista de Biología Tropical, 2016
Histochemistry of the digestive gland of the pearl oyster Pinctada imbricata (Pterioida: Pteriida... more Histochemistry of the digestive gland of the pearl oyster Pinctada imbricata (Pterioida: Pteriidae) during the gametogenic cycle, Venezuela. Histochemical 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.
Boletin Del Centro De Investigaciones Biologicas, 2007
Se evaluo el efecto del petroleo crudo sobre el crecimiento y la concentracion de clorofila a en ... more Se evaluo el efecto del petroleo crudo sobre el crecimiento y la concentracion de clorofila a en las microalgas del nororiente de Venezuela Tetraselmis sp. (G1), Chaetoceros sp. (A1) y Dunaliella salina (C1), cultivadas en sistemas discontinuos bajo condiciones controladas de temperatura (25 ± 1 °C), iluminacion (39,0625 μEm2/s, fotoperiodo 12:12) y salinidad (37 UPS). Los cultivos fueron expuestos por 96 h a diferentes concentraciones (0, 10, 25 y 50 %) de una fraccion acuosa de petroleo durante las diferentes fases de crecimiento microalgal. El crecimiento fue evaluado a las 6, 12, 24, 48 y 96 h mediante el recuento celular y contenido de clorofila a al inicio, 48 y 96 h. La fraccion acuosa del petroleo influyo sobre el crecimiento y la concentracion de clorofila a, produciendose una disminucion significativa y proporcional al incremento de la concentracion del contaminante. Los mayores efectos se evidenciaron a partir de la concentracion de 25%, generalmente a las 6 h, mostrando que Chaetoceros sp. (A1) posee mayor sensibilidad en la fase logaritmica inicial y Dunaliella salina (C1) en la fase estacionaria. Chaetoceros sp. (A1) fue la microalga que presento los valores mayores de clorofila a, a las 96 h, en las tres fases de crecimiento, estableciendose su maximo en la fase estacionaria (3,4 ± 0,31 pg/cel al 10%), mientras que Dunaliella salina (C1) mostro los valores menores de 0,30 ± 0,13 pg/cel al 50 % del contaminante a las 96 h en fase estacionaria. El crecimiento y el contenido de clorofila a de las microalgas evidencian la sensibilidad al petroleo, lo cual sugiere recomendarlas para analisis ecotoxicologicos de corta duracion.
Revista Colombiana De Biotecnologia, Jun 1, 2013
Crecimiento y composición bioquímica de Limnothrix sp. a diferentes salinidades y concentraciones... more Crecimiento y composición bioquímica de Limnothrix sp. a diferentes salinidades y concentraciones de nitrato Growth and biochemical composition of Limnothrix sp. at different salinities and concentrations of nitrate
Ciencias Marinas
How to cite Complete issue More information about this article Journal's homepage in redalyc.org ... more How to cite Complete issue More information about this article Journal's homepage in redalyc.org Scientific Information System Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Non-profit academic project, developed under the open access initiative
Zootecnia Tropical
We evaluated the energy substrates contained in the gonads of a population of brown mussel Perna ... more We evaluated the energy substrates contained in the gonads of a population of brown mussel Perna perna, located of the Caribbean Sea (Northeastern Venezuela). Specimens were collected monthly, by free diving and autonomous, February 2000-January 2001. To this end, 675 organizations were selected, taking into account sex and reproductive stage. In both sexes, but especially in females, was observed the occurrence of stages of maturity and spawning throughout the year, thus suggesting a continuous playback. As for the falls seen in the dry weight of the gonadal lobes, these corresponded to a temporary basis (April to May
Revista de biología tropical, 2005
We evaluated the biological feasibility of massive larvae and postlarvae production of the Caribb... more We evaluated the biological feasibility of massive larvae and postlarvae production of the Caribbean green-white urchin Lytechinus variegatus. Experiments were designed to choose the initial larval density and microalgae diets under culture, to study metamorphosis, postlarval and juvenile growth. Massive production of competent larvae 650 microm long at 12-13 days is possible using larval densities of 0.25 to 1 larva/ml. The microalgae Rhodomonas sp. was suitable for the optimization of larval growth and survival. Metamorphosis of 100% of the larvae can be induced with films of bentic diatoms (Navicula sp. and Amphora sp.), after 96 h; however, diatoms are not adequate for postlarval development and a food supply of Ulva lactuta is necessary for proper growth. For juveniles, a diet of macroalgae (U. lactuta) and/or commercial marine shrimp culture pellet food is enough for growth, but the best results were obtained with shrimp or U. lactuta used alone (85-86%, against 46% with the m...
The effect of density on growth and secondary production of Euvola ziczac was studied under suspe... more The effect of density on growth and secondary production of Euvola ziczac was studied under suspended culture conditions from June 1988 to January 1989. Seven different densities were ex- amined, using juveniles from 9.6 k 0.3 mm long and 5.17 f 0.6 mg dry weight, which were previously cultivated under hatchery conditions. The growth rate in size and biomass was