ABSTRACT The present study aimed to test the effect of three stocking densities: 100, 200, and 300 ind m-3 (D100, D200, and D300, respectively) on survival, growth (weight and total length), and condition factor of Microphis brachyurus. At the end of the six-week trial, there were no significant differences in the fish's survival, growth, and condition. The results suggest that this species presents high adaptability under culture conditions. A suboptimal stocking density generates a suboptimal use of infrastructure and decreases the production system's profitability. Based on the present study, a stocking density of 300 ind m-3 is recommended to increase the aquaculture infrastructure's profitability for ornamental or conservation purposes.

ABSTRACT This study aimed to evaluate the effects of mushroom meal supplementation, Pleurotus djamor var. roseus (Pd), on the diet of Nile tilapia (Oreochromis niloticus), on hematological parameters and growth performance for 60 days. Nile tilapia fingerlings (3.23 ± 0.19 g) were fed with three experimental diets based on the mushroom meal in different percentages: diet 0% control (MM0), diet 15% (MM15), diet 20% (MM20) and diet 25% (MM25). Blood samples from the fish of all treatments were collected at the start of the experiment (day 0), 30 and 60 days. The weight and size of the fish were determined every 15 days (0, 15, 30, 45 and 60 days). The results showed a significant dose-dependent increase in the levels of erythrocytes count and leukocytes count. The groups that showed significant differences in the basal value and the final control result were hematocrit, hemoglobin, and lymphocyte. An increase in lymphocytes proportion and a decrease in neutrophils were found, which was related to the immune response of fish fed the diet. The highest levels of leukocytes, lymphocytes, and low neutrophils were presented in the diet with 15 and 20% (P < 0.05). The growth (weight gain and specific growth rate) of fish fed MM15 and MM20 of Pd in the diet was higher than the control group (P > 0.05). Dietary supplementation (15 and 20%) improved hematological and defense blood cells, as well as the growth of tilapia.

ABSTRACT The present work is a review of the literature on the native Mexican fish Dormitator latifrons. The aim is to contribute to the integration and systematization of current knowledge to make it easier to identify existing knowledge gaps and breakthroghs Moreover, promote the successful cultivation and protection of this species whose consumption is increasing in Latin America. A review of the articles related to D. latifrons published in international and regional databases was carried out. The articles reviewed focus on taxonomy and systematics, phylogenetic, geographic distribution, ecology, physiology, reproduction, development, pathology, health, and the technologies used to cultivate this fish species. The conclusion is that, even though the cultivation of D. latifrons is of commercial interest in some countries, there are still significant gaps in our knowledge of biology and, consequently, the domestication potential of the species. Filling these gaps will require systematic research efforts on protecting natural populations and improving mass cultivation techniques.

ABSTRACT The objective of this work was to assess the acceptance of live and inert food by Macrobrachium tenellum during the early larval stages. The larvae were obtained by collecting wild ovigerous females in the Ameca River in the State of Jalisco, Mexico. Eight treatments (diets) were used to feed the larvae: D1, control (fasting); D2, micro-pulverized food (Purina®); D3, living, newly hatched nauplii of Artemia franciscana (INVE®, Salt Lake City, Utah, USA); D4, commercial paste containing microalgae (Instant Algae Rotifer Diet®); D5, water extracted from a biofloc system; D6, cooked egg yolk; D7, newly hatched and frozen nauplii of A. franciscana (INVE®, Salt Lake City, Utah, USA); D8, nutritional supplement for shrimp larvae (Epifeed LH1®). Treatments D2, D5, D6 and D8 showed traces of food in the digestive system. The larvae did not consume D3 and D7 treatments. The diets that had more acceptance were micro-pulverized food, a nutritional supplement for shrimp larvae Epifeed® LH1, cooked egg yolk, and biofloc water.

ABSTRACT Short-tailed pipe fish (Microphis brachyurus) is a freshwater organism with high economic potential for the aquarium hobby, so it is necessary to implement methods to promote its culture through studies of digestive physiology. General activities of acid and alkaline proteases were evaluated, as well as the effect of pH, temperature and inhibitors. The optimal pH of stomach proteases was 2, while the optimal pH of intestinal proteases was 10. Optimal temperature for the acidic proteases was 35 ºC, while for alkaline proteases it was 45 ºC. Thermal stability showed high resistance at 35 ºC for both acid and alkaline proteases (above 100% residual activity). Acid proteases are resistant at pH 2 (50% of residual activity), meanwhile alkaline proteases were highly resistant at pH 10 (90% of residual activity). Acid proteases were inhibited by 80% with pepstatin A and alkaline proteases were inhibited with TLCK and TPCK for trypsin (75%) and chymotrypsin (80%), respectively. Finally, metallo-proteases were 75% partially inhibited some serine proteases by 75% with EDTA. In conclusion, M. brachyurus has a good digestive capacity, since they can degrade a wide variety of proteins due to their greater proteolytic activity.

RESUMEN El pez pipa (Microphis brachyurus) es un organismo dulceacuícola con alto potencial económico para la acuarofilia; sin embargo, es necesario implementar su cultivo a través de estudios de fisiología digestiva. Se evaluó el efecto del pH, temperatura e inhibidores sobre las actividades enzimáticas de proteasas ácidas y alcalinas. El pH óptimo de proteasas estomacales es de 2, mientras que el de proteases intestinales es de 10. La temperatura óptima de proteasas ácidas es de 35 ºC y las alcalinas de 45 ºC. La estabilidad térmica para proteasas ácidas y alcalinas es a los 35 ºC (más de 100% de actividad residual). La estabilidad a los diferentes pH de las proteasas ácidas es en 2 (50 % de la actividad residual), mientras que para las proteasas alcalinas es en 10 (90 % de la actividad residual). Las proteasas ácidas fueron inhibidas en 80% con pepstatina A y las proteasas alcalinas fueron altamente inhibidas con TLCK para tripsina (75%) y TPCK quimitripsina (80%). Finalmente, las metaloproteasas fueron inactivadas con EDTA en 70%. En conclusión, M. brachyurus tiene una buena capacidad digestiva al degradar una amplia variedad de proteinas debido a su alta actividad proteolítica.

ABSTRACT This work aimed to determine the optimum stocking density of Penaeus vannamei, cultured in a photo-heterotrophic intensive circular system inlined grow-out ponds with minimal water replacement. Five intensive density levels (100, 300, 500, 700 and 900 ind m-3) were considered. The water quality measured for the 98 days grow-out period was within the adequate range for P. vannamei. TAN, nitrate and total phosphorus water quality were significantly higher (P < 0.05) at the higher density. Growth rates and survival decreased as density increased after 300 org m-3. Based on the results of this study, it was found that shrimp grows adequately in high biomass density (99.21 kg tank-1) and density of 500 ind m-3 in an intensive photo-heterotrophic system with a maximum harvest weight of 10 g.

Abstract 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.

Resumen 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.

ABSTRACT An assay on tilapia Oreochromis niloticus and freshwater prawn Macrobrachium americanum in polyculture was conducted during 112 days to study the effect on their blood chemistry and biochemical body composition to determine the feasibility of this polyculture in high density. Six densities were evaluated [T4/5, T9/5, T14/5, T0/5, T9/0, and T14/0; [Ttilapia/prawn (ind m-2)]. In tilapia were evaluated hemoglobin, red cells albumin, globulin, cholesterol, glucose, and triglycerides composition in blood. In M. americanum were evaluated hemocyanin, cholesterol, triglycerides, glucose and total protein in hemolymph. The total content of proteins, lipids, and carbohydrates in muscle and liver of tilapia, and muscle and hepatopancreas on prawns were also studied. Both animals presented significant differences (P < 0.05) in the glucose concentration, tilapia at T9/5 density presented significantly lower concentration (26.25 ± 6.3 mg dL-1) in blood, and prawn at T4/5 presented significant higher concentration (12.2 ± 1.9 mg dL-1). Tilapia monocultures T14/0 displayed significant higher (P < 0.05) carbohydrate concentration in muscle. No significant differences (P > 0.05) appeared in the concentration of lipids and proteins in any tilapia group and proximal composition of muscle and hepatopancreas in prawn. The present study indicates that polyculture in a density T14/5 is similar than monoculture with no effect in blood or hemolymph chemistry and proximal composition of tilapia and prawn. The blood glucose concentration can be considered an indicator of physiological changes for tilapia and prawn when cultured together.

Abstract The aim of this study was to evaluate the growth performance and survival of the Pacific white shrimp (Litopenaeus vannamei) with red tilapia hybrid (Red Florida: Red Yumbo) and spotted rose snapper (Lutjanus guttatus), stocked at different densities in intensive brackish water mix-culture systems compared with monoculture of shrimp. The experiment, conducted in twenty-one plastic tanks (750 L) was set up to evaluate water quality, growth; production and survival of shrimp, tilapia, and snapper, for 60 days. Three replicates were assigned to seven treatments: After 30 day, initial densities were unfolded (shrimp = 50 ind m−3, tilapia = 16 ind m−3 and red snapper = 8 ind m−3). Feeding rate was adjusted at 5 and 10% of body weight d−1 for shrimp and fish, respectively. The shrimp-tilapia mix cultures produced the higher nitrogen and phosphorus in water concentrations. Significant lower survival values were obtained for shrimp (60.0 ± 0.6%) cultured with snapper and for tilapia (79.0 ± 3.1%) reared with shrimp. Mean final biomass for shrimp, tilapia and snapper were higher for the mix-cultures (2.04, 7.7 and 2.9 fold increase, respectively) with respect to their initial biomass. The mix culture system allowed an increase in total production with lower feed conversion ratios, thus contributing with the system sustainability.

Abstract Climate change has broken the natural equilibrium and has modified the state of health of different commercial species such as the geoduck clam. Therefore, the objective of the present study was to predict the distribution of the geoduck clam Panopea globosa of the Gulf of California to the year 2050 using a climate change model. We applied the maximum entropy model (MaxEnt), which considered 12 environmental variables that affect thermal, chemical, and biological distribution. The MaxEnt model predicted the potential habitat suitable for P. globosa with high success rates (Area Under the Curve [AUC] = 0.995). The most favorable habitat of P. globosa is located of Guaymas, Sonora, mainly due to the upwelling of nutrients that promotes the production of chlorophyll-a. In the year 2050, MaxEnt forecasted southward reduction towards the south coast of Sonora, of Santa Rosalía and San Marcos Island in Baja California Sur the presence probability decreased from 0.70 to 0.04. Current clam harvesting sites were observed to have been altered by the social and economic conditions of coastal communities. We conclude that this study is important for fisheries resource management purposes because the fisheries harvesting sites could be affected by climate change.

Resumen El cambio climático ha roto el equilibrio natural y se ha modificado el estado de salud de las diferentes especies comerciales como la almeja de sifón. Por lo tanto, el objetivo del presente estudio fue pronosticar la distribución de almeja de sifón Panopea globosa del Golfo de California en el año 2050 ante un escenario de cambio climático. Se usó el modelo de máxima entropía (MaxEnt) utilizando 12 variables ambientales que afectan la distribución desde el punto de vista térmico, químico y biológico. El modelo de MaxEnt predijo el hábitat potencial adecuado para P. globosa con altas tasas de éxito (Area Under the Curve [AUC] = 0.995). El hábitat más favorable de P. globosa se encuentra en Guaymas, Sonora, debido a la surgencia de nutrientes que benefician la producción de clorofila-a. Para el año 2050, el modelo MaxEnt pronosticó que en Sonora se presentará una reducción hacia la costa sur. En Santa Rosalía e Isla San Marcos, Baja California Sur, las probabilidades disminuyen de 0.70 a 0.04. Los actuales sitios de captura se notarán alterados con posibles afectaciones sociales y económicas en las comunidades litorales. La conclusión es que el estudio resulta importante para la administración de recursos pesqueros, ya que en un escenario de cambio climático los sitios de captura pueden modificarse.

Diploid and triploid Crassostrea gigas oysters were cultivated at three farms (Guasave, Navolato and Ahome) in Sinaloa, Mexico, to evaluate their growth and economic performances. Growth rate and survival of oysters were compared in long-line cultivation and were mostly affected by water parameters rather than ploidy or their interaction. The highest growth rates for shell length (8.01 mm month-1) and body weight (9.08 g month-1) were obtained for the Ahome/triploid group. Survival differed significantly from 98.6% for the Guasave/triploids to 76.7% for the Ahome/diploids. After the first production cycle, more than 80% of production costs represent the purchase of cultivation equipment and salaries contributed with around 9%. The Guasave farm produced the highest profits (US$8,053.71 diploids, US$8,182.19 triploids). Use of diploids starting the production cycle on October-November to avoid mortality and improve final profit is recommended.

The study aimed to evaluate the effect of 4 levels of dietary protein (20, 30, 40 and 50%) and lipids (2, 4, 8 and 16%) on the magnitude and duration of specific dynamic action (SDA) and postprandial nitrogen excretion in the subadult white shrimp Litopenaeus vannamei using computer-controlled metabolic chambers (continuous-flow respirometer). We determined the oxygen consumption rate at 1 h intervals until the postprandial oxygen consumption rate returned to the pre-feeding level. Shrimp fed all the diets had significantly higher respiration rates after feeding due to the SDA. Oxygen consumption, the SDA coefficient and the SDA magnitude increased notably with increasing dietary protein content. Shrimp fed the 20% protein diet had the lowest levels of pre- and post-feeding respiration and the smallest SDA. A significant change in the SDA coefficient relative to each lipid level was not demonstrable. Additionally, nitrogenous excretion increased with an increase of dietary protein but not with an increase of lipid level. By estimating the SDA of subadults, the response to standard metabolic rate (SMR) was lower than that reported for juveniles and postlarva white shrimp.

El objetivo del estudio fue evaluar el efecto de 4 niveles de proteína (20, 30, 40 y 50%) y lípidos (2, 4, 8 y 16%) sobre la magnitud y duración de la acción dinámica específica (ADE) y la excreción nitrogenada en subadultos del camarón blanco Litopenaeus vannamei usando una cámara metabólica controlada por computadora (respirómetro de flujo continuo). Se determinó la tasa de consumo de oxígeno a intervalos de 1 hora hasta que la tasa de consumo de oxígeno postprandial regresó al nivel de pre-alimentación. Los camarones alimentados con todas las dietas tienen una tasa de respiración significativamente alta después de la alimentación debida a la ADE. El consumo de oxígeno, el coeficiente de ADE y la magnitud de ADE aumentó notablemente con el incremento del contenido de proteína en la dieta. Los camarones alimentados con el 20% de proteína en la dieta tuvieron el nivel más bajo de respiración de pre y post-alimentación y la más baja ADE. Un cambio significativo en el coeficiente de ADE relativo a la energía digestible no fue demostrado para cada uno de los niveles de lípidos. Adicionalmente, la excreción nitrogenada aumento con el incremento del nivel de proteína en la dieta, pero no con el incremento del nivel de lípidos. Al estimar la ADE de subadultos se encontró que la tasa metabólica estándar (SMR) fue menor que la reportada para juveniles y postlarvas de L. vannamei.

The aim of this study was to investigate the effects of organic (molasses) and inorganic (Nutrilake®) fertilization on plankton, water quality, and shrimp Litopenaeus vannamei performance reared in zero-discharge tanks and ponds. The findings showed that in tanks, the organic fertilization induced highest survival and production, and low total ammonia-N concentration; however, this effect was not observed in the ponds. In both tanks and ponds, the inorganic fertilization increased nitrogen levels. The phytoplankton abundance increased in both tanks/ponds with the fertilization treatments. Shrimp production in the tanks and ponds fertilized almost doubled compared with unfertilized treatments.

Shrimps are an important resource in coastal lagoons because they use these ecosystems for their development. Although some authors classified the Penaeidae as detritivores, it was shown that their diet comprises a greater variety of food items. Many authors had reported that shrimps have a diversified diet that includes several elements of the benthic community. This review describes the feeding ecology of the shrimps in coastal lagoon-estuarine systems, with emphasis on the following: the effect of the environment on the shrimps’ natural food; techniques for identification of items in shrimps gut contents and stable isotope compositions; consideration of the importance of plants and small animals in the diet; and the effect of mangroves and lagoon-estuarine system on feed ecology. The abundance of penaeid appears to be primarily affected by stochastic variations in environmental factors. However, it has been found that the relationships between macroinfauna, macrofauna and environmental conditions in a tropical estuary may result in more interactions with their predators than a direct response to physical-chemical factors. The combination of the study of shrimps guts contents and stable isotopes shows a composition and seasonal variation in the diets, as well as the source of carbon and nitrogen contained in the shrimp’s tissues. In general, the studies suggest that herbaceous detrital inputs to the food web are dominant in supporting shrimps in salt marshes, but phytoplankton or benthic algae may be equally or more important food sources.

Los camarones son recursos importantes en las lagunas costeras porque utilizan el ecosistema para su desarrollo. Aunque algunos autores clasifican a los camarones Penaeidae como detritívoros, se encontró que su dieta comprende una gran variedad de ítems. Muchos autores han reportado que los camarones tienen una dieta diversificada que incluye varios elementos de la comunidad béntica. Esta revisión describe la ecología alimentaria de los camarones en los sistemas lagunar- estuarinos, con énfasis sobre los siguientes aspectos: el efecto del ambiente sobre el alimento natural de los camarones; técnicas para la identificación de ítems en los contenidos estomacales de los camarones y la composición de isotopos estables; consideraciones sobre la importancia de las plantas y pequeños animales en la dieta; y el efecto de los manglares y sistema lagunar-estuarino sobre la ecología alimentaria. La abundancia de peneidos parece ser principalmente afectado por variaciones estocásticas en factores ambientales. Sin embargo, se ha encontrado que las relaciones entre macroinfauna, macrofauna y condiciones ambientales en un estuario tropical pueden resultar en más interacciones con sus depredadores que una respuesta directa a factores fisico-químicos. La combinación del estudio de los contenidos estomacales e isotopos estables muestra la composición y las variaciones estacionales en las dietas, también, como la fuente de carbón y nitrógeno contenida en el tejido de los camarones. En general, los estudio sugieren que la entrada de detritus herbáceos al tejido de alimentos son dominantes en la alimentación de los camarones en las marismas, pero el fitoplancton o las algas bénticas pueden ser fuentes de alimento igual o más importantes que los detritus herbáceos.

This paper analyzes inter-annual (1993-2008) and intra-annual (2006-2008) flooding patterns in the unregulated San Pedro River, based on digital analysis of two Landsat satellite imagery series and ancillary rainfall and discharge data, to describe variations in the natural pulse. The long-term pattern, over a period of 16 years, showed considerable fluctuations, with a maximum flood extent (FE) of approximately 200 km², while the observed average was 57.8 km² over the entire period, around 24 km² the dry season and more than 90 km² in the rainy season. The seasonal variation, analyzed using 29 quasi-monthly images recorded from 2006 to 2008, displayed FE peaks in the rainy season (July to October) with variations in time and extent that were not directly related to rainfall but instead were related to river discharge, Q, (FE = y0 + a(1-0.9983Q); R² = 0.91). We used the above exponential model with monthly average river discharge data (1944-2008) and the proposed regulated volume of discharge from governmental plans to construct a dam on the San Pedro River. We found that the natural ecosystem will be altered by increasing the inundation in the dry season and reducing it in the rainy season. This change will have consequences in coastal wetlands and aquatic biota adapted to historical conditions, with consequences for the production of aquatic organisms and for ecosystem services.

De acuerdo al análisis digital de dos series temporales de imágenes del satélite Landsat y datos de precipitación y flujo, se analizaron los patrones de inundación inter-anual (1993-2008) e intra-anual (2006-2008) del Río San Pedro, para describir variaciones en su pulso natural. En largo plazo (16 años), se detectaron amplias fluctuaciones con una superficie máxima de inundación (FE) cercana a 200 km² y una extensión media anual de 57,8 km², con promedios aproximados de 24 y 90 km² para las temporadas seca y lluviosa, respectivamente. La variación intra-anual, evaluada a partir de 29 imágenes, registradas con periodicidad cuasi-mensual en el periodo 2006-2008, mostró máximos de FE en la temporada lluviosa (julio a octubre), con diferencias en tiempo y espacio, no relacionadas directamente con la precipitación, sino asociadas con el escurrimiento (Q) del río, (FE = y0 + a(1-0,9983Q); R² = 0,91). Este modelo exponencial se aplicó a una serie temporal con datos promedio mensuales de escurrimiento (1944-2008) y con los volúmenes de descarga regulada propuestos para el plan de construcción de una presa en el Río San Pedro. Se concluye que los ecosistemas naturales serán alterados con un aumento de la superficie inundada durante la época de sequía y una reducción en la época de lluvia. Este cambio tendrá consecuencias sobre los humedales costeros y la biota acuática adaptada a condiciones desarrolladas históricamente, con consecuencias para la producción de organismos acuáticos y para los servicios ecosistémicos.