The performance of the winged pearl oyster Pteria colymbus juveniles under suspended culture cond... more The performance of the winged pearl oyster Pteria colymbus juveniles under suspended culture conditions was evaluate, including five culture methods and two seasons: upwelling and non-upwelling. Culture methods comprised enclosures confining the oysters: BTBC, BBOand BTO; and two other unconfined-oyster: OFOB and FNS. The initial shell height of the oysters ranged between 31–35 mm in both seasons. The increase in shell size and dry mass of soft tissues showed significant differences between seasons. Greatest growth occurred with the OFOB and FNS unconfined methods. The ANOVA II analysis showed significant differences between the variables obtained in both stations and culture methods. Principal Component Analysis showed that the interactions between the variables: temperature (inverse relationship), and UI, chl-a and POM (direct relationship) explained 89 % of the variability of the growth of the oysters. Given the low survival rates, attributed to the presence of predators within t...
Lightning strikes have been observed to study the lightning phenomena particular to a system in w... more Lightning strikes have been observed to study the lightning phenomena particular to a system in which both UHV designed and 500kV designed transmission lines coexist. This observation covers the lightning phenomena through lightning strikes, surge propagation on transmission lines and generation of overvoltages in substations. This paper describes the study of the lightning phenomenon of a shielding failure to aUHV designed line and the analysis result by the EMTP, which are based on the observation result of the lightning surge at a substation.
The Pacific or Japanese oyster, Crassostrea gigas, was introduced into Ecuador in 1990; however, ... more The Pacific or Japanese oyster, Crassostrea gigas, was introduced into Ecuador in 1990; however, little is known about its cultivation in the Eastern Tropical Pacific. This study analyzes growth and the influence of environmental factors on two cohorts of C. gigas held in pearl nets suspended from a long line, in Ayangue Bay,
The present study examines the influence that environmental variables exerted on changes in condi... more The present study examines the influence that environmental variables exerted on changes in condition index (CI), shell height (SH-dorsal-ventral axis) and soft tissue mass increments (STM) of the winged oyster Pteria colymbus in suspended culture during periods of upwelling (December to April) and non-upwelling (August to November) in the Cariaco Gulf, northeastern Venezuela. Environmental variables recorded between April 2012 and May 2013 included seston, water transparency, temperature, dissolved oxygen, chlorophyll a (Chl a) and the upwelling index (UI). Individuals were cultivated in lantern nets with an overall density of 56 individuals/0.123 m 2. From three randomly chosen baskets, five individuals were sampled each month and changes in CI, STM and SH were related to the environmental variables using Spearman correlation and PCA. Results show that during upwelling, both Chl a and UI presented a positive and significant relationship with the oyster condition and growth parameters. During non-upwelling (low UI), this relationship was inverse, demonstrating the important influence of upwelling and non-upwelling periods on the ecophysiology of the species. Furthermore, it was shown that the non-upwelling, characterized by high temperatures and low food availability, is a critical period for P. colymbus,
The effects of mono-and bi-microalgal diets on shell length, organic tissue, and survival of Spon... more The effects of mono-and bi-microalgal diets on shell length, organic tissue, and survival of Spondylus limbatus juveniles were tested in two separate feeding experiments. The first examined nine single species of microalgae: Chaetoceros gracilis, C. muelleri, Isochrysis aff. galbana (T-ISO), Tetraselmis chuii, T. maculata, Pavlova lutheri, Dunaliella salina, Rhodomonas sp., and Nannochloropsis sp. An extra treatment maintaining the juveniles in a long line culture was at Ayangue Bay, Province of Santa Elena, Ecuador. Single diets of P. lutheri, C. muelleri, and C. gracilis showed the best combined growth of survival performance in juveniles, and were therefore selected for the bi-algal diet experiment design with the inclusion of I. galbana T-ISO due to its recommended use in bivalve culture. A second experiment consisted in selecting the best three microalgae species that resulted from the first experiment and combined each other in binary treatments at 1:1 ratio. All bi-algal diets in combination with P. lutheri showed good result in growth (shell and biomass), yield, and survival. However, single P. lutheri mono-algal diet showed equal or better performance index than the other bi-algal combined diets, demonstrating the pertinence in using this microalga as food for S. limbatus juveniles.
ABSTRACT The rock oyster Striostrea prismatica is one of the most abundant species in the rocky c... more ABSTRACT The rock oyster Striostrea prismatica is one of the most abundant species in the rocky coastal ecosystems of the tropical and subtropical eastern Pacific; however, natural banks are overexploited or depleted, so production by culture is recommended. Adult S. prismatica obtained from natural banks were conditioned for gonad maturation and spawning. Fertilization, embryogenic, and larval development were performed under laboratory conditions, then settlement of pediveliger larvae and nursing of postlarvae were performed using downwelling methods to produce spat. The early life cycle (embryonic, larval, and postlarval development up to 5 mm in length) is described. The larval development was completed in 22 days, with survival >25%. The larval and postlarval growths were exponential reaching spat size (5 mm) after 28 days of settlement. The methods used in this study supported successful larval and postlarval culture of S. prismatica and provide a basis for large-scale propagation of this species.
The growth, survival and influence of environmental factors were analysed in two cohorts of cultu... more The growth, survival and influence of environmental factors were analysed in two cohorts of cultured Pteria sterna in Ayangue Bay, Province of Santa Elena, Ecuador (tropical Eastern Pacific). Juveniles representing cohorts I and II (8.4 ± 0.54 and 5.0 ± 0.17 mm in dorso-ventral axis) were deployed in November 2015 and February 2016, and grown in pearl nets suspended in a long line for 12 and 10 months respectively. The stocking density was monthly and bi-monthly reduced during sampling of individuals to determine growth in dorso-ventral shell axis, dry mass of shell, soft tissues and dry mass of fouling on shell. Water temperature, salinity, total seston and phytoplankton biomass (chlorophyll a) were determined at the culture site. Results showed that P. sterna reached ~100 mm in length during the first year of culture. Although little negative influence of environmental factors was detected, high temperatures during the reproduction period can be the most negative influential trait. The highest tissue mass (6 g), which occurred at the 10th month of cultivation, as well as a high availability of spat by artificial collectors in the coastal waters, showed that the species can be considered a good candidate for aquaculture in the tropical eastern Pacific.
Antibiotics have been used massively for aquatic organism production. However, their use should b... more Antibiotics have been used massively for aquatic organism production. However, their use should be limited given the problems of increased antibiotic resistance, and new alternatives should be attempted, such as the use of plants extracts with antibacterial properties. The effect of the essential oil of oregano (Origanum vulgare) compared with three antibiotics (enrofloxacin, florfenicol, and oxytetracycline) on embryogenesis and early larval stages were evaluated to obtain mixotrophic larvae of the scallop Nodipecten subnudosus. Incubation densities of 20 and 100 fertilized oocytes mL -1 were used. The highest yield of normal larvae (calcified Dlarvae) occurred at high densities in an order of 300% (36-45 D-larvae mL -1 ), with the highest values being obtained when the fertilized oocytes were treated with the oregano essential oil and with the antibiotic florfenicol, 44.8 ± 5.16 and 40.9 ± 12.06 D-larvae mL -1 , respectively. Nevertheless, the use of florfenicol produced larvae with shorter anteroposterior length, which strengthens the advantage of using oregano essential oil over the antibiotics for spat production of N. subnudosus.
The Pacific oyster Crassostrea gigas is one of the mollusks with greater production on a globa... more The Pacific oyster Crassostrea gigas is one of the mollusks with greater production on a global scale. The success of its cultivation depends mainly on the production of seeds under controlled conditions, for which the quality of water used is a preponderant factor. Production of C. gigas spat was evaluated, both in the larval and pediveliger stages, under physical and chemical treatments commonly used in the production of invertebrates. The different water treatments were based on the filtration and exposure of water to ultraviolet light-UV (1-control treatment) and its variants with the addition of hypochlorite + thiosulfate, hypochlorite + vitamin C, hypochlorite + thiosulfate + ethylenediaminetetraacetic acid -EDTA, hypochlorite + thiosulfate + vitamin C + EDTA and oxytetracycline antibiotic. The results, expressed in less time of larval development, higher growth rate and size of larvae competent to the...
El efecto de la dosis subletal de cadmio 0,05 mg/L en la ostra perla del Caribe Pinctada imbricat... more El efecto de la dosis subletal de cadmio 0,05 mg/L en la ostra perla del Caribe Pinctada imbricata se evaluo en organismos de tres tallas diferentes: juveniles de 10–20 mm, 40-45 y adultos > 75 mm. Los bioensayos estaticos se llevaron a cabo durante 7 dias con una renovacion del metal en el cuarto dia de exposicion. Al final del bioensayo, se evaluo la reposicion de la concha, masa de tejido, consumo de oxigeno y relacion ARN/ADN. No se observaron efectos significativos del cadmio en niveles subletales sobre la masa de tejido, indice de ARN/ADN y consumo de oxigeno, en cada una de las tallas. No obstante, a esta concentracion de cadmio se registro una disminucion significativamente en la reposicion de la concha en los organismos juveniles. La utilizacion de reposicion de concha en juveniles de P. imbricata es recomendada como indicador biologico para establecer pruebas de toxicidad. P alabras clave : Ostras perla Akoya, toxicidad, ARN/ADN, consumo de oxigeno, Golfo de Cariaco. AB...
Estudiamos la influencia de las variables ambientales asociadas con tres profundidades de agua (2... more Estudiamos 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 en partículas (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) con 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...
Latin American Journal of Aquatic Research, Nov 10, 2019
The bivalve Nodipecten subnodosus is one of the largest scallop species and has been selected as ... more 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 29ºC), 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.
The performance of the winged pearl oyster Pteria colymbus juveniles under suspended culture cond... more The performance of the winged pearl oyster Pteria colymbus juveniles under suspended culture conditions was evaluate, including five culture methods and two seasons: upwelling and non-upwelling. Culture methods comprised enclosures confining the oysters: BTBC, BBOand BTO; and two other unconfined-oyster: OFOB and FNS. The initial shell height of the oysters ranged between 31–35 mm in both seasons. The increase in shell size and dry mass of soft tissues showed significant differences between seasons. Greatest growth occurred with the OFOB and FNS unconfined methods. The ANOVA II analysis showed significant differences between the variables obtained in both stations and culture methods. Principal Component Analysis showed that the interactions between the variables: temperature (inverse relationship), and UI, chl-a and POM (direct relationship) explained 89 % of the variability of the growth of the oysters. Given the low survival rates, attributed to the presence of predators within t...
Lightning strikes have been observed to study the lightning phenomena particular to a system in w... more Lightning strikes have been observed to study the lightning phenomena particular to a system in which both UHV designed and 500kV designed transmission lines coexist. This observation covers the lightning phenomena through lightning strikes, surge propagation on transmission lines and generation of overvoltages in substations. This paper describes the study of the lightning phenomenon of a shielding failure to aUHV designed line and the analysis result by the EMTP, which are based on the observation result of the lightning surge at a substation.
The Pacific or Japanese oyster, Crassostrea gigas, was introduced into Ecuador in 1990; however, ... more The Pacific or Japanese oyster, Crassostrea gigas, was introduced into Ecuador in 1990; however, little is known about its cultivation in the Eastern Tropical Pacific. This study analyzes growth and the influence of environmental factors on two cohorts of C. gigas held in pearl nets suspended from a long line, in Ayangue Bay,
The present study examines the influence that environmental variables exerted on changes in condi... more The present study examines the influence that environmental variables exerted on changes in condition index (CI), shell height (SH-dorsal-ventral axis) and soft tissue mass increments (STM) of the winged oyster Pteria colymbus in suspended culture during periods of upwelling (December to April) and non-upwelling (August to November) in the Cariaco Gulf, northeastern Venezuela. Environmental variables recorded between April 2012 and May 2013 included seston, water transparency, temperature, dissolved oxygen, chlorophyll a (Chl a) and the upwelling index (UI). Individuals were cultivated in lantern nets with an overall density of 56 individuals/0.123 m 2. From three randomly chosen baskets, five individuals were sampled each month and changes in CI, STM and SH were related to the environmental variables using Spearman correlation and PCA. Results show that during upwelling, both Chl a and UI presented a positive and significant relationship with the oyster condition and growth parameters. During non-upwelling (low UI), this relationship was inverse, demonstrating the important influence of upwelling and non-upwelling periods on the ecophysiology of the species. Furthermore, it was shown that the non-upwelling, characterized by high temperatures and low food availability, is a critical period for P. colymbus,
The effects of mono-and bi-microalgal diets on shell length, organic tissue, and survival of Spon... more The effects of mono-and bi-microalgal diets on shell length, organic tissue, and survival of Spondylus limbatus juveniles were tested in two separate feeding experiments. The first examined nine single species of microalgae: Chaetoceros gracilis, C. muelleri, Isochrysis aff. galbana (T-ISO), Tetraselmis chuii, T. maculata, Pavlova lutheri, Dunaliella salina, Rhodomonas sp., and Nannochloropsis sp. An extra treatment maintaining the juveniles in a long line culture was at Ayangue Bay, Province of Santa Elena, Ecuador. Single diets of P. lutheri, C. muelleri, and C. gracilis showed the best combined growth of survival performance in juveniles, and were therefore selected for the bi-algal diet experiment design with the inclusion of I. galbana T-ISO due to its recommended use in bivalve culture. A second experiment consisted in selecting the best three microalgae species that resulted from the first experiment and combined each other in binary treatments at 1:1 ratio. All bi-algal diets in combination with P. lutheri showed good result in growth (shell and biomass), yield, and survival. However, single P. lutheri mono-algal diet showed equal or better performance index than the other bi-algal combined diets, demonstrating the pertinence in using this microalga as food for S. limbatus juveniles.
ABSTRACT The rock oyster Striostrea prismatica is one of the most abundant species in the rocky c... more ABSTRACT The rock oyster Striostrea prismatica is one of the most abundant species in the rocky coastal ecosystems of the tropical and subtropical eastern Pacific; however, natural banks are overexploited or depleted, so production by culture is recommended. Adult S. prismatica obtained from natural banks were conditioned for gonad maturation and spawning. Fertilization, embryogenic, and larval development were performed under laboratory conditions, then settlement of pediveliger larvae and nursing of postlarvae were performed using downwelling methods to produce spat. The early life cycle (embryonic, larval, and postlarval development up to 5 mm in length) is described. The larval development was completed in 22 days, with survival >25%. The larval and postlarval growths were exponential reaching spat size (5 mm) after 28 days of settlement. The methods used in this study supported successful larval and postlarval culture of S. prismatica and provide a basis for large-scale propagation of this species.
The growth, survival and influence of environmental factors were analysed in two cohorts of cultu... more The growth, survival and influence of environmental factors were analysed in two cohorts of cultured Pteria sterna in Ayangue Bay, Province of Santa Elena, Ecuador (tropical Eastern Pacific). Juveniles representing cohorts I and II (8.4 ± 0.54 and 5.0 ± 0.17 mm in dorso-ventral axis) were deployed in November 2015 and February 2016, and grown in pearl nets suspended in a long line for 12 and 10 months respectively. The stocking density was monthly and bi-monthly reduced during sampling of individuals to determine growth in dorso-ventral shell axis, dry mass of shell, soft tissues and dry mass of fouling on shell. Water temperature, salinity, total seston and phytoplankton biomass (chlorophyll a) were determined at the culture site. Results showed that P. sterna reached ~100 mm in length during the first year of culture. Although little negative influence of environmental factors was detected, high temperatures during the reproduction period can be the most negative influential trait. The highest tissue mass (6 g), which occurred at the 10th month of cultivation, as well as a high availability of spat by artificial collectors in the coastal waters, showed that the species can be considered a good candidate for aquaculture in the tropical eastern Pacific.
Antibiotics have been used massively for aquatic organism production. However, their use should b... more Antibiotics have been used massively for aquatic organism production. However, their use should be limited given the problems of increased antibiotic resistance, and new alternatives should be attempted, such as the use of plants extracts with antibacterial properties. The effect of the essential oil of oregano (Origanum vulgare) compared with three antibiotics (enrofloxacin, florfenicol, and oxytetracycline) on embryogenesis and early larval stages were evaluated to obtain mixotrophic larvae of the scallop Nodipecten subnudosus. Incubation densities of 20 and 100 fertilized oocytes mL -1 were used. The highest yield of normal larvae (calcified Dlarvae) occurred at high densities in an order of 300% (36-45 D-larvae mL -1 ), with the highest values being obtained when the fertilized oocytes were treated with the oregano essential oil and with the antibiotic florfenicol, 44.8 ± 5.16 and 40.9 ± 12.06 D-larvae mL -1 , respectively. Nevertheless, the use of florfenicol produced larvae with shorter anteroposterior length, which strengthens the advantage of using oregano essential oil over the antibiotics for spat production of N. subnudosus.
The Pacific oyster Crassostrea gigas is one of the mollusks with greater production on a globa... more The Pacific oyster Crassostrea gigas is one of the mollusks with greater production on a global scale. The success of its cultivation depends mainly on the production of seeds under controlled conditions, for which the quality of water used is a preponderant factor. Production of C. gigas spat was evaluated, both in the larval and pediveliger stages, under physical and chemical treatments commonly used in the production of invertebrates. The different water treatments were based on the filtration and exposure of water to ultraviolet light-UV (1-control treatment) and its variants with the addition of hypochlorite + thiosulfate, hypochlorite + vitamin C, hypochlorite + thiosulfate + ethylenediaminetetraacetic acid -EDTA, hypochlorite + thiosulfate + vitamin C + EDTA and oxytetracycline antibiotic. The results, expressed in less time of larval development, higher growth rate and size of larvae competent to the...
El efecto de la dosis subletal de cadmio 0,05 mg/L en la ostra perla del Caribe Pinctada imbricat... more El efecto de la dosis subletal de cadmio 0,05 mg/L en la ostra perla del Caribe Pinctada imbricata se evaluo en organismos de tres tallas diferentes: juveniles de 10–20 mm, 40-45 y adultos > 75 mm. Los bioensayos estaticos se llevaron a cabo durante 7 dias con una renovacion del metal en el cuarto dia de exposicion. Al final del bioensayo, se evaluo la reposicion de la concha, masa de tejido, consumo de oxigeno y relacion ARN/ADN. No se observaron efectos significativos del cadmio en niveles subletales sobre la masa de tejido, indice de ARN/ADN y consumo de oxigeno, en cada una de las tallas. No obstante, a esta concentracion de cadmio se registro una disminucion significativamente en la reposicion de la concha en los organismos juveniles. La utilizacion de reposicion de concha en juveniles de P. imbricata es recomendada como indicador biologico para establecer pruebas de toxicidad. P alabras clave : Ostras perla Akoya, toxicidad, ARN/ADN, consumo de oxigeno, Golfo de Cariaco. AB...
Estudiamos la influencia de las variables ambientales asociadas con tres profundidades de agua (2... more Estudiamos 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 en partículas (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) con 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...
Latin American Journal of Aquatic Research, Nov 10, 2019
The bivalve Nodipecten subnodosus is one of the largest scallop species and has been selected as ... more 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 29ºC), 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.
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