Hydraulic and environmental design of a constructed wetland as a treatment for shrimp aquaculture effluents

Shrimp aquaculture has grown to the extent that pressure on natural ecosystems has greatly increased. The shrimp farms effluents usually discharge their wastes, with high nutrients load, into coastal water bodies without any previous treatment. This work presents a method to design a constructed wetland for handling these effluents. Our method is based on a first order equation model and a hydrodynamic numerical model as the main component for the design process. Numerical results showed consistency with the first order theory, when pollutants concentration were reduced to values accepted by the applicable regulations

Numerical modeling of hydrodynamics in the Agua Brava lagoon, located in Nayarit, Mexico

In this paper a study of the hydrodynamics of the Agua Brava lagoon system is performed by numerical modeling. The importance of studying this lagoon system lies with aquaculture activities carried out by shrimp farms. The π-HYDRO model is used for the numerical simulations of hydrodynamics and temperature and salinity dispersion. The boundary conditions regarding ocean properties were generated with the HYCOM ocean model, whereas tides were calculated from the tidal predictions of the MAR V1.0. A hydrological study was also performed to calculate the freshwater contributions and take them into account in the numerical simulations. The scenarios analyzed are the dry and wet seasons particularly for 2013. For the case of the dry season, a slight influence of hydrological contributions to the dynamics of the lagoon is observed, where the effects of the tidal flow are predominant. For the wet scenario, the effects of both tidal and hydrological flow drive the motion within the lagoon, especially being predominant the hydrological flow due to the river discharges in the near region to the shrimp farms

Effects of different dietary of protein and lipid levels on the growth of freshwater prawns (Macrobrachium carcinus) broodstock

Objective. Evaluate the effects of varying dietary protein and lipid levels on the growth and body composition of adult freshwater prawns, Macrobrachium carcinus (Linnaeus 1758), in a recirculation system for 11 weeks (77 days). Materials and methods. The experimental treatments were assigned in triplicate. Six test diets were formulated with three different protein levels (35, 40 and 45%) and two lipid levels (8 and 13%). Results. The highest survival rate, growth indices and feed utilization were observed for M. carcinus adults fed protein:lipid diets of 35:13, 40:13 and 45:13, and the lowest values for these parameters were recorded for prawns fed diets with the lowest lipid levels; the differences in these parameters between these types of diets were significant (p<0.05). A non-significant tendency for an increased percentage of protein in the body with an increased dietary protein level was observed. The percentage of lipids decreased with an increasing dietary protein level, and no definite trends in ash content were found. Conclusions. The results suggest that a diet with 35% dietary crude protein and 13% lipids enhances the growth and body composition of adult M. carcinus

The effect of astaxanthin on resistance of juvenile prawns Macrobrachium nipponense (Decapoda: Palaemonidae) to physical and chemical stress

In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquaculture and its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of different physicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50mg/kg, AX100 with 100mg/kg, and AX150 with 150mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1 000L) used for holding prawns. Three replicate aquaria were initially stocked with 36org/m2 per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5mg/L; and ammonia-nitrogen, 0.05mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75mg/L), and reduced oxygen (0.5mg/L). The time to lethargy and the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed greater reduction than those exposed to other treatments. It is possible that higher levels of astaxanthin in the body under oxygen reduction stress can be beneficial for prawns. These results suggest that male prawns showed lethargy earlier than females, and the percentage of carotenoid reduction in muscle and gill tissues was higher in males.In recent years, the use of new scientific techniques has effectively improved aquaculture production processes. Astaxanthin has various properties in aquaculture and its antioxidant benefits have been closely related to stress resistance; besides, it is an essential factor for growth in many crustaceans and fish. The objective of this study was to evaluate the resistance of prawn (Macrobrachium nipponense) fed diets containing different amounts of astaxanthin (AX) to the shock and stress of different physicochemical environments. A 70-day trial was conducted to evaluate the effect of supplementation of a source of astaxanthin (Carophyll Pink, 10% astaxanthin, w/w, Hoffman-La Roche, Switzerland) at various levels in the diet of M. nipponense juveniles. Four dry diets were prepared: AX0 without astaxanthin, AX50 with 50mg/kg, AX100 with 100mg/kg, and AX150 with 150mg/kg astaxanthin. The feeding trial was conducted in a recirculation water system consisting of 12 fiberglass tanks (1 000L) used for holding prawns. Three replicate aquaria were initially stocked with 36org/m2 per tank. During the trial, prawns were maintained on a 12:12-h light:dark photoperiod with an ordinary incandescent lamp, and the water quality parameters were maintained as follows: water temperature, 25-26°C; salinity, 1g/L; pH, 8.5-8.8; dissolved oxygen, 6.0-6.5mg/L; and ammonia-nitrogen, 0.05mg/L. Incorporation of AX, production output, and physiological condition were recorded after 10 weeks of feeding. At the end of the growing period, the prawns were exposed to thermal shock (0°C), ammonia (0.75mg/L), and reduced oxygen (0.5mg/L). The time to lethargy and the time to complete death of the prawns were recorded. The results showed that control prawns had the shortest time to lethargy and death compared with prawns subjected to the other treatments. The results of this study have shown that the amount of muscle tissue and gill carotenoids in prawn fed with an AX150 diet showed greater reduction than those exposed to other treatments. It is possible that higher levels of astaxanthin in the body under oxygen reduction stress can be beneficial for prawns. These results suggest that male prawns showed lethargy earlier than females, and the percentage of carotenoid reduction in muscle and gill tissues was higher in males

Distribución, abundancia y patrón reproductivo de Pseudupeneus grandisquamis Gill, 1863 (Perciformes: Mullidae) y Urobatis halleri Cooper, 1863 (Rajiformes: Urolophidae) en el Golfo de California

The fish Pseudupeneus grandisquamis and round stingrays Urobatis halleri, are very frequent species in the fauna of accompaniment of the shrimp from the continental platform of Sonora, Sinaloa and Nayarit. The organisms were collected with a shrimp trawl of 30 m length abroad a fleet from Sonora. The network operated within a depth of 9 to 96 m from September 2004 till March 2005. Lengths methods were used. 2463 fish of the P. grandisquamis were collected and 1123 of the U. halleri with sizes between 20 to 230 mm and 30 to 460 mm total length (TL) respectively. Both species showed high distribution and group type in all the study zone. The biggest densities happened in lower depths between 9 and 38 m. The biggest abundances was in October for P. gradisquamis and in December for U. halleri. The dispersion of organisms showed a relationship inversely proportional with the depth, the abundance of organisms diminishes with the increase of the depth. The distribution was heterogeneous with the patterns of the population�s group distribution. The size of first sexual maturity of P. grandisquamis was of 130 mm LT and the recruitment pattern was found to occur throughout the spring and autumn, and the recruitment of U. halleri was found to occur in the summer. Both species share the same habitat, both in coexistence in the demersal marine ecosystem of the Gulf of California.Se analizó la distribución, abundancia relativa y patrón reproductivo del pez chivo (Pseudupeneus grandisquamis) y la manta redonda (Urobatis halleri), especies dominantes en la fauna de acompañamiento del camarón de la plataforma continental de Sonora, Sinaloa y Nayarit. Los organismos fueron recolectados de septiembre de 2004 a marzo de 2005 con red de arrastre camaronera de 30 m de longitud, que operó de 9 a 98 m de profundidad. Se realizaron muestreos biológicos biológicos y se aplicaron métodos basados en longitudes. Se recolectaron 2,463 organismos de P. grandisquamis y 1,123 de U. halleri con tallas de 20 a 230 mm y 30 a 460 mm de longitud total (LT) respectivamente. Ambas especies presentaron una distribución amplia de tipo apiñada en la zona de estudio y abundancia batimétrica mayor de 9 a 38 m y escasos organismos a mayor profundidad, con máxima densidad de 19 a 28 m. Las máximas abundancias fueron en octubre para P. gradisquamis y en diciembre para U. halleri. La abundancia de organismos mostró una relación inversamente proporcional con la profundidad; la abundancia disminuye con el incremento de la profundidad. La talla de primera madurez sexual de P. grandisquamis fue de 130 mm LT y el patrón de reclutamiento mostró que los mayores reclutamientos se presentan en los meses de marzo-abril y septiembre, mientras que para U. halleri fueron de junio a agosto. Ambas especies comparten hábitat, coexistiendo en el ecosistema marino demersal del Golfo de California

Effect of white spot syndrome virus (WSSV) and water exchange on survival and production of Litopenaeus vannamei under semi-intensive culture conditions.

A study was performed in two commercial shrimp farms in the province of Guasave, north of Sinaloa, Mexico, to assess the effects of the presence of the white spot syndrome virus (WSSV) and of water exchange on the growth rate, production, and survival of the Pacific white shrimp, Litopenaeus vannamei, during the fall-winter season in semi-intensive culture ponds. The experiment consisted of four treatments; in the first (T1), three earthen ponds with water exchange, were stocked with PCR-positive for white-spot syndrome virus (WSSV) postlarvae. In the second (T2), three earthen ponds were stocked likewise (PCR-positive), but without water exchange. In the third (T3), three earthen ponds, with water exchange were stocked with PCR-negative for white-spot syndrome virus (WSSV) postlarvae. In the fourth (T4), three earthen ponds were stocked likewise (PCR-negative), but without water exchange. The average growth rates were 0.56, 0.56, 0.80, and 0.75 g/week for T1, T2, T3, and T4, respectively. Survival was 23.2% (T1), 26.1% (T2), 64.3% (T3), and 66.1% (T4). Production ranged between 252.60 and 847.00 kg/ha, with the lowest production in T2 and the highest in T3. Feed conversion ratio ranged from 1.00 for T3 to 1.70 for T2. The final average weight ranged between 10.6 g (T2) to 12.5 g (T3). The WSSV can affect negatively the growth rate (30%), the survival (64%), and the production (69%) in comparison with PCR-negative organisms.No differences in weight were found between WSSV-infected and non-infected individual shrimps, as well as in nested-PCR positive against single-step PCR positive organisms.It found that the zero water exchange strategy could be feasible for the culture of the white shrimp L. vannamei at a commercial level during the fallwinter season

Effect of the initial stocking body weight on growth of spotted rose snapper Lutjanus guttatus (Steindachner, 1869) in marine floating cages

Spotted rose snapper were stocked at body weight sizes of 24.5 �} 3.7 g, 55.4 �} 3.5 g, and 110.2 �} 4.6 g in three replicated marine floating cages of 100 m3 and reared for 153 days at Santa Cruz de Miramar in Nayarit, Mexico, to determine the appropriate stocking body weight size. Caged snapper were fed twice a day with commercial pellets containing 35% crude protein during the first three months and 25% during the last two months, respectively. The water temperature of cages ranged from 25.6 to 32.3��C. Mean survival ranged from 67.5 to 74.7%. Stocking body weight sizes of snapper exerted significantly different (P.0.05) effects on the final biomass. The maximum mean weekly weight gain was 12.8 g week-1 in cages with the 110.2 �} 4.6 g body weight size. These results suggest, as a good strategy, the introduction of snappers with a total weight of 110 g for grow out in marine cages culture.Pargos lunarejos con pesos promedio de 24,5 �} 3,7 g, 55,4 �} 3,5 g y 110,2 �} 4,6 g fueron introducidos para su engorde en jaulas flotantes de 100 m3 por un lapso de 153 dias en Santa Cruz de Miramar, Nayarit, Mexico, con la finalidad de encontrar el peso mas adecuado de cultivo. Los pargos fueron alimentados dos veces al dia con alimento comercial conteniendo 35 y 25% de proteina cruda durante el primero a tercer mes y en el cuarto y quinto mes respectivamente. Durante el experimento, la temperatura del agua vario de 25,6 a 32,3oC. Al final del experimento se obtuvo una supervivencia que fluctuo de 67,5 a 74,7%. Se determinaron, con base en el peso inicial, diferencias estadisticamente significativas (P.0,05) con respecto a la biomasa final cosechada. La maxima ganancia en peso promedio semanal fue de 12,8 g semana-1 en los organismos con el mayor peso inicial (110,2 �} 4,6 g). Esta informacion sugiere que la inclusion de pargos lunarejos con un peso de 110 g puede ser una buena estrategia para el engorde en jaulas flotantes

Efecto de diferentes combinaciones de temperatura y salinidad sobre el consumo específico de oxígeno en el camarón blanco Litopenaeus vannamei

The combined effect of different temperatures (20, 25 and 30°C) and salinities (15, 25, 35 and 45 psu) on the specific oxygen consumption (CEO) in Litopenaeus vannamei was determined. For this, CEO of 248 organisms of different body sizes (0.31 to 15.85 g) was measured. The CEO decreased when shrimp weight increased in all treatments without presenting a definite pattern when the salinity increased; even though all the combinations of temperature and salinity did not statistically show slopes significantly different in the regression models for CEO and organism weight relationships. The slope values suggest that at 20°C there is high energy expenditure at 15 psu, and at 25°C the highest energy consumption occurs at 45 psu. Whereas at 30°C, the lowest energy consumption occurred combined with the lowest salinity (15 psu). This may indicate that the isosmotic condition (point of lowest energy expenditure) tends to change with temperature, which may imply that the shrimp can be cultivated at high temperature (30°C) and at low salinities (15 psu) without increasing energy expenditure.Se analizó el efecto combinado de diferentes temperaturas (20, 25 y 30°C) y salinidades (15, 25, 35 y 45 ups) sobre el consumo específico de oxígeno (CEO) en Litopenaeus vannamei. Se midió el CEO en 248 organismos de distintas tamaños corporales (0,31 a 15,85 g). El CEO disminuyó con el aumento de peso corporal de los organismos en todos los tratamientos, sin observarse un patrón general definido de aumento del CEO conforme se incrementó la salinidad. Aunque no hubo diferencias estadísticas significativas en todas la combinaciones de temperatura-salinidad entre las pendientes de regresión que relacionan el CEO con el peso de los organismos, los valores de pendientes en particular sugieren que en 20°C se da un mayor gasto energético en la menor salinidad (15 ups) y en 25°C en la salinidad más alta (45 ups). Mientras que en 30°C, el menor gasto energético se presentó en la menor salinidad (15 ups). Lo cual puede indicar que la condición isosmótica (punto de menor gasto energético) tiende a modificarse con la temperatura, favoreciendo con ello que los camarones se puedan cultivar en alta temperatura (30°C) y baja salinidad (15 ups) sin que se presente un mayor gasto energético

Efecto de la carga del carbón orgánico sobre la calidad del agua y el sedimento en una granja de cultivo de lutjánidos en jaulas marinas

Se analizó el efecto de la entrada de carbón orgánico en la calidad del sedimento y su correlación con la interfase agua-sedimento y las condiciones hidrográficas en una granja de lutjánidos en jaulas marinas. Los resultados indican que se presenta una correlación de la temperatura del agua y el potencial de oxido reducción en la zona más profunda de la columna de agua con el contenido de carbón orgánico (IOC) en el sedimento. Este resultado permite contar con una herramienta de fácil acceso para conocer en una forma indirecta el enriquecimiento orgánico del sedimento

Environmental variability at a marine cage culture operation in the Matanchén Bay, SE Gulf of California, Mexico

This study investigated the environmental impact of offshore floating sea cages and the influence of runoff on cage fish farming in SE Gulf of California via the analysis of the physico-chemical profiles of the water column and sediments, located in SE Gulf of California, Mexico. Water and sediment samples were analyzed for physico-chemical parameters. In general, nitrates showed the highest concentrations of nutrients in the potential impact station (1.92 mg L-1). The results displayed temporal variations in the NH4 +, NO3 -, and PO4 3- in the water column as well as variations in the clay and organic matter in the sediment. The observed trends of these parameters were toward higher concentration in the potential impact and control stations.Este trabajo presenta los resultados del análisis de las condiciones ambientales sobre el perfil físico-químico de la columna de agua y sedimentos que son producidos por las jaulas flotantes y la influencia de escurrimientos continentales en una granja de peces marina en el Sur este del Golfo de California, México. Veinte muestras de la columna de agua y siete del sedimento fueron colectadas mensualmente durante un ciclo anual. Se analizaron parámetros físico-químicos del agua y del sedimento. En general, los nitratos mostraron la más alta concentración de los nutrientes en las estaciones de la zona de impacto potencial (1,92 mg L-1). Hubo una variación temporal en la concentración de NH4 +, NO3 - y PO4 3- en la columna de agua, y en la concentración de arcilla y materia orgánica en sedimento, con una tendencia a incrementarse en las estaciones de impacto potencial y control, respectivamente