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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.

Shrimp farm aquaculture causes environmental impacts, notably decreased water quality due to the release of nutrient-rich effluents. Pond wastewater is usually discharged without treatment, and tidal conditions are not taken into account in the management plans. However, natural variability of nutrients makes difficult field evaluation and attribution of impacts. Here we implemented a three-dimensional coupled hydrodynamic-biogeochemical model (spatial resolution = 50 m × 50 m, time resolution = 4 s) in order to evaluate the dispersion conditions under specific tidal conditions of nutrient discharges from a semi-intensive shrimp farm during spring and neap tide. Ammonia was quickly assimilated by plankton and its concentration recovered initial levels 10 days after the beginning of the harvest. Due to the higher salinity of the pond effluents, shrimp farm discharges accumulate in waters and sediments of the upper lagoon creeks, mostly affecting the benthos, thus implying a potential risk of shrimp farm self-contamination. Maximum concentrations of most biogeochemical tracers occurred when the harvest ends and the ponds are fully emptied. We show that maximum nutrient concentrations can be reduced by ~ 10% when the harvest ends during spring tides compared to harvests ending during neap tides. This work may be useful to improve the management of shrimp farm effluents by reducing, easily and at little cost, nutrient impacts on tropical and sub-tropical receiving ecosystems.

Shrimp farm aquaculture causes environmental impacts, notably decreased water quality due to the release of nutrient-rich effluents. Pond wastewater is usually discharged without treatment, and tidal conditions are not taken into account in the management plans. However, natural variability of nutrients makes difficult field evaluation and attribution of impacts. Here we implemented a three-dimensional coupled hydrodynamic-biogeochemical model (spatial resolution = 50 m × 50 m, time resolution = 4 s) in order to evaluate the dispersion conditions under specific tidal conditions of nutrient discharges from a semi-intensive shrimp farm during spring and neap tide. Ammonia was quickly assimilated by plankton and its concentration recovered initial levels 10 days after the beginning of the harvest. Due to the higher salinity of the pond effluents, shrimp farm discharges accumulate in waters and sediments of the upper lagoon creeks, mostly affecting the benthos, thus implying a potential risk of shrimp farm self-contamination. Maximum concentrations of most biogeochemical tracers occurred when the harvest ends and the ponds are fully emptied. We show that maximum nutrient concentrations can be reduced by ~ 10% when the harvest ends during spring tides compared to harvests ending during neap tides. This work may be useful to improve the management of shrimp farm effluents by reducing, easily and at little cost, nutrient impacts on tropical and sub-tropical receiving ecosystems.

The South American fur seal (SAFS) is distributed from Peru (Pacific Ocean) to Uruguay (Atlantic Ocean). However, there is a section of coastline of about 2,300 km along the Chilean coast where no SAFS are recorded. Based on morphological comparisons 3 geographic forms have been reported (Peruvian, South Chilean, Atlantic), whereas preliminary genetic studies suggest the presence of 3 distinct genetic types (Peruvian, South Chile, Atlantic). However, both of these approaches are support only the existence of 2 independent evolutionary histories for SAFS (Peruvian, Atlantic), in which case, we would also expect to find some differences in the species' life histories among these locals populations (e.g., in the timing of the breeding season). In this study, we compare the breeding seasons of SAFS at Punta Pichalo (19°36'S-Chile), Isla Guafo (43°33'S-Chile), and Isla de Lobos (35°01'S-Uruguay) with data published for Punta San Juan (15°21'S-Peru). The periods for establishing territories, pupping, and mating took place on similar dates at Isla Guafo and Isla de Lobos, but occurred about a month earlier at Punta Pichalo and Punta San Juan. Pupping peaked at Isla Guafo on 15- December, at Isla de Lobos on 17- December, and at Punta Pichalo on 27- November. These differences in timing were not related to demographic, oceanographic or photoperiod conditions of the breeding sites under study, neither is related with the latitudinal effects on the breeding phenology. Based on results, we suggest that certain characteristics of life history can help identify species with independent evolutionary histories., El lobo fino Sudamericano (SAFS) se distribuye desde Perú hasta Uruguay. Sin embargo, existe un área de 2,300 km a lo largo de la costa de Chile donde no se registran ejemplares de SAFS. A partir de comparaciones morfológicas se ha identificado la presencia de 3 formas geográficas (Peruana, Chilena austral y Atlántica), a la vez que estudios moleculares preliminares sugieren la presencia de 3 tipos genéticos distintivos (Peruana, Chilena austral y Atlántico). Sin embargo, ambas aproximaciones apoyan la existencia de 2 historias evolutivas independientes para los SAFS (Peruana, Atlántica), en cuyo caso, se podría esperar encontrar similares diferencias también en aspectos de la historias de vida de la especie entre estas poblaciones locales (e.g., en el tiempo de la estación reproductiva). En este estudio, se comparó la estación reproductiva de ejemplares del SAFS establecidas en Punta Pichalo (19°36'S-Chile), Isla Guafo (43°33'S-Chile), e Isla de Lobos (35°01'S-Uruguay) con otros datos publicados para Punta San Juan (15°21'S-Perú). El periodo de formación de los harenes, el periodo de pariciones y el de cópulas ocurrieron en fechas semejantes en Punta Pichalo y Punta San Juan y aproximadamente un mes más tarde en Isla Guafo e Isla de Lobos. El máximo de pariciones se registró en Isla Guafo el 15 de diciembre, en Isla de Lobos el 17 de diciembre, y en Punta Pichalo el 27 de noviembre. Estas diferencias no estuvieron relacionadas con las características demográficas, ni con las condiciones oceanográficas o con el fotoperiodo de las colonias bajo estudio, ni tampoco estaría relacionado con el efecto latitudinal sobre la fenología reproductiva. En base a los resultados, se sugiere que ciertas características de las historias de vidas pueden también ayudar a identificar especies con historias evolutivas independientes.

Juveniles of the white shrimp Litopenaeus vannamei were exposed during 25 days to the Cu2+ concentration commonly used in Mexican shrimp farms, at salinities of 1, 5, and 10 psu, in order to observe possible histological alterations to the antennal glands, midgut, gills and hepatopancreas. Survival was 100% in controls and treatments, and no histopathologies were observed in gills, midgut and antennal glands. Sloughing of epithelial cells (< 75%), infiltration of hemocytes (< 75%) and reduction in R and B cells (100%) were observed after 10 days in the hepatopancreas of shrimps exposed to Cu2+ at the lowest salinity and, to a lower degree, at salinities of 5 and 10 psu. This should be taken into consideration to establish criteria of acceptable water quality for inland aquaculture, because the interaction metal-salinity may induce adverse shrimp responses., Juveniles del camarón blanco Litopenaeus vannamei fueron expuestos durante 25 días a salinidades de 1, 5, y 10 ups y a la concentración de Cu2+ que se usa comúnmente en las granjas camaronícolas de México, con el propósito de observar posibles alteraciones histológicas en la glándula antenal, intestino medio, branquias y hepatopáncreas. La supervivencia fue de 100% en controles y tratamientos y no se observaron histopatologías en branquias, intestino y glándula antenal. Después de 10 días de exposición al Cu2+ a la salinidad más baja, se observaron en el hepatopáncreas desprendimiento de las células epiteliales (< 75%), infiltración de hemocitos (< 75%), y una reducción de las células R y B (100%). Las mismas alteraciones se presentaron, aunque en menor grado, a las salinidades de 5 y 10 ups. Estos efectos deberían ser considerados para establecer criterios de calidad de agua para el cultivo de camarón en agua continentales, debido a que la interacción metal-salinidad puede inducir respuestas adversas en los camarones.

Ishige sinicola (Setchell et Gardner) Chihara, Rosenvingea antillarum (P.L. Crouan et H.M. Crouan) M.J. Wynne, Sargassum sinicola Setchell et Gardner, Scinaia johnstoniae Setchell, Gracilaria turgida Dawson and Lithophyllum margaritae (Hariot) Heydrich at the coast of Sinaloa, Mexico were recorded for the first time. Each species is presented with data regardin their morphology, reproductive status, habitat and geographic distribution., Se registran por primera vez a Ishige sinicola (Setchell et Gardner) Chihara, Rosenvingea antillarum (P.L. Crouan et H.M. Crouan) M.J. Wynne, Sargassum sinicola Setchell et Gardner, Scinaia johnstoniae Setchell, Gracilaria turgida Dawson y Lithophyllum margaritae (Hariot) Heydrich para la costa de Sinaloa, México. Cada especie se presenta con datos relativos a su morfología, estado reproductivo, hábitat y distribución geográfica.