Scielo RSS <![CDATA[Latin american journal of aquatic research]]> http://www.scielo.cl/rss.php?pid=0718-560X20170001&lang=en vol. 45 num. 1 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[<b>Culture conditions for <i>Hippocampus</i> spp. (Teleostei: Syngnathidae)</b>: <b>research in the XXI century</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100001&lng=en&nrm=iso&tlng=en Las poblaciones de caballito de mar (género Hippocampus) han sido impactadas de diferentes formas por el ser humano. Por esta razón, se han implementado medidas para mitigar el decremento de las poblaciones, como su inclusión en la lista de CITES, lo cual regula en parte su comercialización. Sin embargo, se deben adoptar otras medidas para asegurar la conservación de estas especies. La acuicultura se presenta como una oportunidad que puede traer beneficios en diferentes formas: reemplazando la captura del medio natural, repoblando cuerpos de agua cuyas poblaciones se encuentren impactadas y como actividad económica redituable. Desde inicios del presente siglo, se ha generado información relevante en torno a las condiciones de cultivo de diferentes especies de caballito de mar, desde los parámetros físicos y químicos del agua y otras condiciones físicas como tipos y tamaños de los tanques, hasta cuestiones relacionadas con la nutrición, la supervivencia, el crecimiento, la maduración y el proceso reproductivo. En este trabajo se recopila esta información, con énfasis en las investigaciones relacionadas con las especies americanas.<hr/>The seahorse populations (genus Hippocampus) have been impacted in different ways by humans. For this reason, measures have been implemented to mitigate the decline of populations, as their inclusion in the list of CITES, which regulates in part the trade between countries. However, other measures must be taken to ensure the conservation of these species. Aquaculture is presented as an opportunity that can bring benefits in different ways: replacing capture from natural environments, repopulating water bodies whose populations are impacted and as a profitable economic activity. From the beginning of this century, relevant information has been generated about the culture conditions of different species of seahorses, from the physical and chemical parameters of water and other physical conditions such as types and sizes of tanks, to issues related to nutrition, survival, growth, maturation and reproductive processes. This paper presents a collection of such information, with some emphasis on works related to species in the Americas. <![CDATA[<b>Feeding n-3 HUFA enriched <i>Artemia</i> to the larvae of the pink shrimp <i>Farfantepenaeus paulensis</i> increases stress tolerance and subsequent growth</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100002&lng=en&nrm=iso&tlng=en There has been a considerable amount of work on the effects of Artemia enrichment on shrimp larvae. However, the effects on the subsequent growth performance have not been thoroughly investigated. From mysis I to eight day-old postlarvae (PL8), shrimp (Farfantepenaeus paulensis) were fed either newly hatched Artemia nauplii or Artemia enriched with an emulsion containing high levels of n-3 highly unsaturated fatty acids (n-3 HUFA). Upon reaching PL8, shrimp were exposed to salinity and ammonia stress tests. Growth performance was assessed by further rearing shrimp for 40 days. Shrimp fed the enriched Artemia (named EG) had higher tolerance to both salinity and ammonia than those fed newly hatched Artemia (named CG). Weight of PL from EG was also significantly higher than in CG. Higher levels of n-3 HUFA, especially 20:5 n-3 and 22:6 n-3, were found in the enriched Artemia. In the postlarvae, higher levels of n-6 and n-3 HUFA were observed in EG, while PL from CG presented higher levels of 18:3 n-3 and 18:4 n-3. At the end of the nursery rearing, no differences in survival were observed, but weight was higher in EG (1.08 g) than in CG (0.90 g). The supplementation of n-3 HUFA during larviculture increases the tolerance of F. paulensis postlarvae to salinity and ammonia, and positively affects growth performance after a 40 days long rearing period. <![CDATA[<b>Stress analysis of a submersible longline culture system through dynamic simulation</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100003&lng=en&nrm=iso&tlng=en This study analyzed the stresses on a submersible longline culture system subjected to both parallel and perpendicular oceanographic conditions of 0.5 and 1 m s-1 current velocity with 2 to 5 m wave height, using a dynamic simulation model based on the finite element method. Results indicated that when the culture system is submerged, the stress on mooring lines, the main line and whip lines decreases until a 55%. Additionally, changing the direction of the current and waves results in differences ranging from -59% to 312%. It was established that in an environment involving high-energy events, it is structurally possible to submerge the longline culture system in a direction parallel to oceanographic parameters, which could have positive implications for reducing the loss of cultivated biomass and improving productive conditions. <![CDATA[<b>The rocky reef fishes of Vermelha Beach, a marine-estuarine transitional zone at Guanabara Bay, Brazil</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100004&lng=en&nrm=iso&tlng=en Rocky reefs are one of the most important biotopes in Guanabara Bay due to their broad distribution and high species diversity. This study aimed to describe the composition and structure of the fish assemblage associated with rocky reefs in Vermelha Beach (RJ/Brazil), an estuarine-marine transitional zone located at the entrance of Guanabara Bay. Fish were surveyed through underwater visual censuses, conducted by snorkeling divers along 10 m²-linear transects (n = 90). A total of 2.487 fishes were recorded belonging to 29 species in 18 families. Except for Atherinella brasiliensis, all other species are intimately associated with rocky reefs. The present work also stresses the importance of further studies to evaluate the role of periodic influences of estuarine and oceanic waters as structuring factors of the fish assemblages associated with rocky reefs at Vermelha Beach and similar ecosystems. <![CDATA[<b>Scaling copepod grazing in a coastal upwelling system</b>: the importance of community size structure for phytoplankton C flux]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100005&lng=en&nrm=iso&tlng=en Crustacean zooplankton, often dominated by copepods and euphausiids, are the major phytoplankton grazers in coastal upwelling systems. It has been argued that zooplankton grazing is a size-dependent process, such that models incorporating the size structure of zooplankton are appropriate for describing herbivore C-transfer. Here, based on the size-spectrum theory and on gut-fluorescence experiments, conducted with numerically dominant copepods from two upwelling sites off the Chilean coast, we show that C-specific ingestion rates of copepods are size-dependent. We further show that the size structure of the copepod community, synthesized by the slope of the normalized size spectrum, determines the impact of grazing on phytoplankton. C-specific ingestion rates, depending on species size, were in the range of 0.14-353.97 (ng C μg C-1 h-1). A modelled normalized biomass-spectra of a copepod community in the size range of 0.5 to 74.0 μg C showed that C-specific grazing impact can increase by a factor of 4 when small-sized species (0.1-10 μg C ind-1), such as Paracalanus cf. indicus, Acartia tonsa, Oncaea spp. and Corycaeus spp., dominate the community in terms of biomass. By contrast, when larger-sized copepods dominate (10-100 μg C ind-1), such as Calanus chilensis, Calanoidespatagoniensis and Rhyncalanus nasutus, total zooplankton biomass may increase, but with a sharp decrease in the efficiency of C transfer via herbivores. Our findings indicate that processes affecting the size structure of zooplankton communities can substantially impact the phytoplankton C flux through the pelagic food web, thus controlling production of higher trophic levels. <![CDATA[<b>Theoretical study of antiparasite products dispersion in closed systems baths used by salmon industry in Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100006&lng=en&nrm=iso&tlng=en Se desarrolló e implementó un modelo teórico para el estudio de la dispersión de fluidos en los procedimientos de baños sanitarios en la industria del salmón. El modelo está basado en un autómata celular con el método redes de Lattice Boltzmann, ampliamente utilizado para la simulación de fluidos. El estudio contempla la simulación de incorporación del producto antiparasitario en un volumen de agua, y su posterior dispersión en el ambiente. Los resultados muestran que el procedimiento, utilizado en la actualidad por la industria del salmón, es eficiente para algunas configuraciones especiales de implementación del baño, alcanzando una cobertura de biomasa superior al 75%. El estudio de sensibilidad de parámetros en el modelo indicó que la densidad de peces (kg m-3), el diámetro (mm) de las perforaciones de las mangueras usadas para inyectar la mezcla antiparasitaria, el tamaño de la jaula y la distancia entre las perforaciones, no son determinantes en la eficiencia y eficacia del sistema para distribuir el producto. En cambio la potencia de la bomba, la forma y razón de aspecto de la jaula, y la disposición de las mangueras, influyen en la cobertura del tratamiento. Finalmente, los resultados de las simulaciones de dispersión del producto antiparasitario fuera de la jaula, indican que el principio activo sería indetectable entre 30 y 90 m corriente abajo de la ubicación de la jaula, pocos segundos después de retirada la lona del baño.<hr/>A theoretical model was developed to study the dispersion of fluids in the sanitary bath procedures, currently used by the salmon industry. The model uses a cellular automaton with the Boltzmann's networks method, widely used for simulation of fluids. The study simulates the incorporation of the anti-parasite active ingredient in a volume of water and its subsequent dispersion in the environment. The results show that the sanitary bath procedure is efficient for some special configurations of bath implementation, achieving higher coverage of 75% biomass. For the range of values used in the model, the analysis of sensibility show that the densities of fishes, the diameters of the hose drilling, the size of the cage and the distance between drilling, are not determinant in the efficiency and effectiveness of the system for the distribution of the product. Instead, the power pumps, the shape and the ratio aspect of the cage and arrangement of the hoses, itself do influence on coverage. Finally the results of our simulations scattering outside the cage, shown that the active ingredient would be undetectable between 30 and 90 m of the location of the cage in the current flow direction, few seconds after removing the canvas. <![CDATA[<b>Physical, chemical and zooplankton biomass variability (inshore-offshore) of Mexican Central Pacific during El Niño-La Niña 2010</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100007&lng=en&nrm=iso&tlng=en The response of zooplankton, phytoplankton biomass (Chl-a concentration) and nutrients to the oceanographic variability in the Mexican Central Pacific was studied over three oceanographic surveys realized in 2010 (January, May and October). The highest zooplankton biomass (48 mL 1000 m-3) was registered in May when nitrites, nitrates, phosphates and silicates were also highest and mean Chl-a was 0.67 mg m-3. The lowest zooplankton biomass was registered in October, with a mean value of 25 mL 1000 m-3. Twenty-nine taxonomic groups of zooplankton were recorded, of which copepods contributed 71% of total abundance followed by chaetognaths (6%) and euphausiids (5%). Multivariate BEST test demonstrated that mixed layer depth and temperature at 25 m depth can explain the distribution of major zooplankton groups. The study area was influenced by El Niño conditions, which caused a seasonal shift. Coastal upwelling was evident until late summer, when geostrophic analysis showed a predominant SW component near the Jalisco coast. We suggest a possible top-down control of zooplankton grazing over phytoplankton, and acclimatization of both plankton groups to variability in environmental conditions induced by the transition from warm to cold ENSO phase. <![CDATA[<b>Infestation of <i>Pseudione tuberculata</i> (Isopoda: Bopyridae) on juveniles of <i>Lithodes santolla</i> (Magellan region, Chile)</b>: <b>a spatial mesoscale analysis</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100008&lng=en&nrm=iso&tlng=en We document latitudinal patterns of infestation of the bopyrid parasite isopod Pseudione tuberculata on southern king crab Lithodes santolla juveniles (20-77 mm carapace length) recruited to fishing grounds in the southern Chilean fjord system. Seven hundred and fifty individuals were collected by semi-autonomous diving in 11 of 21 sampling locations in the study area, along the western margin of the Magellan region between August and October 2013.The prevalence of P. tuberculata varied between 0 and ~22%, and displayed a spatial pattern associated with three areas: i) northern Beagle Channel (10 to ~22%; lengths between 37 and 47 mm), ii) northwestern Navarino Island without infestations (0%; 26-55 mm), and iii) Piazzi Island-Capitán Aracena Island (0-12%; 50-77 mm). Infestations were independent of host sex, while parasite prevalence decreased with host length. No parasites were observed on crabs longer than 60 mm. A comparison of slopes between linearized length-weight regressions suggests that parasitized individuals had lower weight growth than uninfested individuals. Both southern king crab juvenile density and P. tuberculata prevalence were higher in fishing areas towards Beagle Channel where previous research reported lower average surface water temperatures (<6.5°C) and higher surface water salinity (&gt;30). The study area covers five zones relevant for the conservation and protection of sub Antarctic biodiversity, and provides opportunities for large-scale geographic studies of the host-parasite relationship. <![CDATA[<b>Taxonomic update and illustrated key of Zeiformes from Chile (Pisces: Actinopterigii)</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100009&lng=en&nrm=iso&tlng=en The Chilean fishes of the order Zeiformes are rare in museum collections, the lack of scientific expeditions to the submarine ridge and the scarcity of new specimens records in Chilean shelves, as well as the lack of biological studies, probably accounts for its apparent rarity. In the last two decades, fishes of the order Zeiformes in Chile have undergone major changes in their taxonomic categories and in the record of new species. In Chile, there are five families, 7 genera and 11 species. They live in benthic and bathypelagic realms and are distributed at depths of 30 to 1500 m. Also, the literature of these species, is scattered, hindering their taxonomic and systematic knowledge, which makes difficult their study and better understanding as a group. It also prevents progress in such important aspects like their phylogenetic relationships, the state of vulnerability of their populations and other biological aspects. In order to contribute to the knowledge and its identification, a bibliographical compilation and a tentative illustrated identification key that unifies all the existing information in a single document, is presented. This may constitute a new tool to contribute to the growing interest in biodiversity studies in the south eastern Pacific Ocean. <![CDATA[<b>Free radical scavenging activity of extracts from seaweeds <i>Macrocystis pyrifera</i> and <i>Undaria pinnatifida</i></b>: <b>applications as functional food in the diet of prawn <i>Artemesia longinaris</i></b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100010&lng=en&nrm=iso&tlng=en Water-soluble extracts from seaweeds Macrocystis pyrifera (M) and Undaria pinnatifida (U) were prepared to use the polysaccharide bioactive fraction as functional food. Chemical analysis showed that the main components of both extracts were mannitol and fucoidans. Also in both cases minor amounts of rhamnose, glucose, xylose and arabinose were determine. Content of fucose+galactose was higher in U. pinnatifida (8.7%) than in M. pyrifera (5.9%). Extracts were used as feed additive to Artemesia longinaris at inclusion levels of 1 and 2% (M1 and M2; U1 and U2), a diet without extract was used as control. Radical scavenging activities were estimated for two extracts and for midgut gland samples of experimental animals. Scavenging activity was detected in both extracts, the signal decayed to 50 and 62% in 18 min for U. pinnatifida and M. pyrifera, respectively. After 30 days of feeding, results did not show variation of survival, but growth was improved in animals fed with U1 and U2. Supplementation with 1 and 2% of U. pinnatifida showed similar quenching capacity of homogenates than those fed with M2 with a rapid 1,1-diphenylpicrylhydrazyl (DPPH) decay at 2 min of reaction. Recommended concentration for culture A. longinaris is 2%, as it is that produce the best antioxidant capacity, although the growth performance was improved also significantly only with U. pinnatifida extract. <![CDATA[<b>Historical biogeography of the squids from the family Loliginidae (Teuthoidea: Myopsida)</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100011&lng=en&nrm=iso&tlng=en La clausura del Mar de Tetis y la apertura del Océano Atlántico jugarían un papel relevante en la historia de los calamares de la familia Loliginidae, lo que se reflejaría en su actual distribución nerítico-costera, según la hipótesis vicariante propuesta por Brakoniecki (1986). Este estudio evalúa esta hipótesis y otras ideas alternativas para entender la historia del grupo, sobre la base de una hipótesis filogenética, reconstruida con secuencias mitocondriales y nuclear, que incorpora la incertidumbre, permitiendo estimar tiempos de divergencia para sugerir un nuevo escenario histórico sustentado en la señal filogenética y reconstrucción de la distribución ancestral. Los resultados permiten inferir que Loliginidae se habría originado en el Pacífico Oeste durante el Paleoceno Tardío hace unos 59 Ma, y que durante su diversificación habrían ocurrido al menos 20 eventos de dispersión históricos y 6 de vicarianza. El primer evento de vicarianza fragmenta la distribución ancestral permaneciendo el ancestro de Sepioteuthis en el rango sur y la subfamilia Loligininae en el rango norte. Luego, sucesivos eventos de dispersión, y algunos de vicarianza desvinculados del movimiento de placas tectónicas y apertura del Océano Atlántico, modelaron su distribución. La presente inferencia apunta a un origen distinto al propuesto por Brakoniecki (Mar de Tetis), coherente con un centro de origen que sustenta la mayor diversidad de la familia, con predominancia de los procesos de dispersión (como se evidencia en todos los géneros considerados, salvo Heterololigo), restringidos a desplazamientos nerítico-costeros, que explicarían el patrón de distribución actual.<hr/>According to the vicariant hypothesis proposed by Brakoniecki (1986) the closure of the Sea of Tethys and the opening of the Atlantic Ocean would play an important role in the history of squids of the family Loliginidae, which is reflected in its current neritic distribution. Our study evaluated this hypothesis and alternative ideas to understand the historical biogeography of loliginid squids. This work is based on a phylogenetic hypothesis rebuilt with mitochondrial and nuclear sequences that incorporates the estimation of divergence times and ancestral distribution. Our results sustain that the squids of the family Loliginidae would have originated in the Western Pacific during the Late Paleocene about 59 My, following, during their diversification, at least 20 dispersion and 6 vicariant events. The first vicariant event fragments the ancestral distribution, remaining the ancestor of Sepioteuthis in the south and the subfamily Loligininae in the north. Successive events of dispersion, and some of vicariance (unrelated with the movement of tectonic plates and opening of the Atlantic Ocean), modeled it distribution. Our inference suggest a different origin compared to proposed by Brakoniecki (Tethys Sea), consistent with a center of origin that supports the most diversity of the family, with a predominance of dispersion processes over vicariant events, which explain the present distribution pattern. <![CDATA[<b>Effect of dietary chitin on digestive enzyme activity, growth and survival of <i>Macrobrachium tenellum</i> juvenile prawns</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100012&lng=en&nrm=iso&tlng=en Macrobrachium tenellum is a freshwater prawn native from Mexico to Peru, with potential for cultivation. Currently, it is extensively exploited by local fisheries. To understand its chitin requirements, a formulated diet with chitin added (5, 10 15, 20, and 25%) was given to juveniles for 60 days. Growth, survival, and enzyme activity (trypsin, chymotrypsin, lipase, amylase, and chitinase) were measured every 15 days. Highest final weight and specific growth rate resulted from diets with 20% chitin. Poorest performance resulted from diets with 5 and 10% chitin. Chitin in the diet did not have a significant effect on survival. Statistically significant differences in enzyme activity were not found in any treatment. <![CDATA[<b>Gametogenic cycle of the oyster, <i>Pinctada imbricata,</i> in suspended culture in the Gulf of Cariaco, Venezuela</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100013&lng=en&nrm=iso&tlng=en La ostra perla, Pinctada imbricata es una especie autóctona que potencialmente puede ser usada para la acuicultura en el Golfo de Cariaco. Se examinó el desarrollo gonadal mensual de una cohorte de juveniles (27,38 ± 2,70 mm) de la ostra perla en un sistema de cultivo suspendido. El desarrollo gonádico se analizó durante todo el periodo de estudio (abril 2012-febrero 2013), alcanzando el primer máximo de madurez sexual a los cinco meses de la fijación. Las hembras mostraron un descenso sostenido del índice gonadal a partir de diciembre asociado al período de surgencia, mientras que los machos presentaron fluctuaciones que corresponden a desoves parciales sin vaciar completamente las gónadas. La mayor frecuencia de desoves durante la surgencia, cuando existe mayor disponibilidad de alimento sugiere que posee una estrategia reproductiva oportunista. La proporción sexual se mantuvo uniforme en el lapso de estudio con una mayor abundancia de machos (53%) al inicio del cultivo, mostrando que la etapa de transición sexual de cambio de sexo se observó en una baja proporción de la población. Además, el desarrollo gametogénico, estuvo asociado con la productividad primaria (Cl-a) y disponibilidad partículas orgánicas en el medio ambiente (seston orgánico). En cultivo, la ostra alcanzó una talla de 43,85 ± 5,66 mm. El incremento en tamaño de la concha fue mayor durante los primeros cinco meses, deteniéndose en un desove parcial asociado a una alta producción primaria, a partir del cual disminuyó el incremento en el tamaño de la concha, pero aumentó la producción de gametos.<hr/>The pearl oyster, Pinctada imbricata is an indigenous species that can potentially be used for aquaculture in the Gulf of Cariaco. In this work we examined the monthly gonadal development of a juvenile cohort (27.38 ± 2.70 mm) of the pearl oyster in a hanging culture system. Gonadal development was recorded throughout the study period (April 2012-February 2013), reaching the first maximum sexual maturity within five months of fixation. The females showed a sustained decrease of the gonadal index from December associated to the upwelling period, whereas the males presented oscillations that correspond to partial spawning without completely emptying the gonads. The greater frequency of spawning during upwelling, when there is greater availability of food, suggests that he has an opportunistic reproductive strategy. The sex ratio remained unchanged in the study period with a tendency to have more males (53%) at the beginning of the culture, evidencing that the stage of sexual transition of sex change is experienced by a low proportion of the population. Gametogenic development, in turn, was associated with primary productivity (Chl-a) and the availability of organic particles (organic seston). In culture, the oyster reached a size of 43.85 ± 5.66 mm. The increase in shell size was high during the first five months, stopping associated with a partial spawning with high primary production, from which the increase of the shell decreased in exchange for higher gametes production. <![CDATA[<b>Ecological distribution of <i>Nematopalaemon schmitti</i> and <i>Exhippolysmata oplophoroides</i> (Crustacea: Caridea) near an upwelling area off southeastern Brazil</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100014&lng=en&nrm=iso&tlng=en Regions affected by upwelling show environmental characteristics that may change the distribution of the species. This study evaluated the influence of environmental factors on the spatiotemporal distribution of two caridean shrimps, Nematopalaemon schmitti and Exhippolysmata oplophoroides, in a region of the Brazilian coast affected by Cabo Frio upwelling. Shrimps were collected monthly from July 2010 through June 2011 off Macaé off the northern coast of Rio de Janeiro State, at six locations: three at 5 m, and the other three at 15 m depth. Shrimp abundance was compared among seasons and sampling sites. Nematopalaemon schmitti (n = 1200) was more abundant at 5 m depth while E. oplophoroides (n = 2176) occurred predominately at 15 m. There were significant seasonal fluctuations in the distribution of the species in the region, resulting from variation in bottom temperature. The presence of the South Atlantic Central Water (SACW) favors the decrease in the abundance of N. schmitti and highest abundance of E. oplophoroides. The abundance of E. oplophoroides and the percentage of organic matter were significantly and positively correlated. The organic matter content in the sediment and water temperature was among the most important variables affecting seasonal distribution of the species. The distinct environmental characteristic between the bathymetric regions were a determinant factor in their spatial distribution. <![CDATA[<b>The copepod <i>Acartia tonsa</i> as live feed for fat snook (<i>Centropomus parallelus</i>) larvae from notochord flexion to advanced metamorphosis</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100015&lng=en&nrm=iso&tlng=en From early development until the completion of metamorphosis, fat snook (Centropomus parallelus) larvae are commonly fed the rotifers Brachionus spp. and Artemia spp. nauplii. In this study, cultivated copepods Acartia tonsa were evaluated as feed for 15-to 45-day-old larvae. Two experiments were performed using twelve 30-L tanks stocked with 3.3 fat snook larvae L-1. Their initial mean weight and length were 1.35 ± 0.01 mg (mean ± standard deviation) and 3.83 ± 0.33 mm for 15-day-old larvae and 2.79 ± 1.2 mg and 6.99 ± 0.88 mm for 31 -day-old larvae. Three dietary treatments were carried out in four replicates, including Rotifer (R), Artemia (A) and/or Copepod (C). Experiment 1 included Diet RA (control), Diet RC and Diet RCA; while experiment 2 included Diet A (control), Diet C and Diet AC. The survival and growth of larvae fed the Diet RCA in experiment 1 were significantly higher than the others. In experiment 2, the inclusion of copepods in the diet did not improve survival and growth, however, larvae fed Diet C had the highest DHA/EPA ratio. We conclude that the copepod Acartia tonsa provides an important nutritional benefit to fat snook larvae undergoing metamorphosis. <![CDATA[<b>Bioremediation and biocontrol of commercial probiotic in marine shrimp culture with biofloc</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100016&lng=en&nrm=iso&tlng=en The use of probiotics within shrimp farms has increased as an alternative to antibiotic use because of an increasing demand for more environment-friendly aquaculture. This has improved growth performance and health of shrimp, and improved pathogen control as well as water and soil quality in culture systems. However, efficacy of probiotics in intensive systems using biofloc remains uncertain. Here, bioremediation and biocontrol of a commercial probiotic was investigated through analysis of water quality and main bacterial groups that influence a Litopenaeus vannamei culture using biofloc. Furthermore, additional knowledge was gained on phytoplankton and shrimp performance. Treatments consisted of four different probiotic concentrations (Bacillus subtilis and B. licheniformis): 0.5 g m-3 (P0.5), 1 g m-3 (P1.0), 2 g m-3 (P2.0), 3 g m-3 (P3.0), and a control without probiotic (CTL). All variables were shown to be balanced and within the recommended limits for shrimp farming. Under the culture conditions adopted in this study, the commercial probiotic did not result in a significant effect (P ≥ 0.05) on water quality, bacteria, phytoplankton, or shrimp performance. Bacteria naturally present in biofloc were sufficient for maintaining the balance of culture and continued to exert excellent bioremediation and biocontrol when management was conducted properly. <![CDATA[<b>Faunal assemblages of intertidal hydroids (Hydrozoa, Cnidaria) from Argentinean Patagonia (Southwestern Atlantic Ocean)</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100017&lng=en&nrm=iso&tlng=en This study provides taxonomical and ecological accounts for the poorly known diversity of hydroids distributed over ~2,000 km of Argentinean Patagonian intertidal habitats (42°-54°S). Sampling was performed in 11 sites with tidal amplitude between 6-13 m dominated by rocky outcrops, breakwaters, and salt marshes. Samples were sorted and identified up to the species level and hydroid associations were analyzed by multivariate analyses. A total of 26 species were recorded. The most frequent species were Amphisbetia operculata, present in 8 of the 10 sites inhabited by hydroids, followed by Symplectoscyphus subdichotomus and Nemertesia ramosa. All recorded hydroids are geographically and bathymetrically widely distributed species, common at the austral hemisphere. Seven species (Coryne eximia, Bougainvillia muscus, Ectopleura crocea, Hybocodon unicus, Halecium delicatulum, Plumularia setacea, and Clytia gracilis) were reported from intertidal fringes. Species richness differed according to the composition of the bottom, topographical complexity and density of mytilid communities. Some muddy intertidal fringes dominated by the glasswort Sarcocornia perennis had an unexpected hydroid fauna composition, never reported for salt marsh habitats, representing a remarkable novelty for the hydroid literature. The lack of studies on the hydroid fauna from these particular habitats represented a substantial gap for our biodiversity knowledge. <![CDATA[<b>Utility of five SSR markers for genetic diversity and paternity exclusion analysis in the Patagonian toothfish</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100018&lng=en&nrm=iso&tlng=en The Patagonian toothfish or Chilean sea bass (Dissostichus eleginoides), found in the Southern Ocean surrounding Antarctica, is an important fishery species for Chile. This high-value species is regarded as overfished, making it an attractive target for aquaculture. When developing a reproduction program for any aquaculture species, it is important to implement genetic tools to evaluate diversity, inbreeding, and parentage. We calculated genetic diversity and paternity/maternity exclusion probabilities based on five commonly-used microsatellite loci in a natural population of Patagonian toothfish from southern Chile (n = 34) in order to evaluate the potential utility of these five markers in stock management. The observed number of alleles per locus (Na) and observed heterozygosities (H O) are within range as described by studies performed in other sub-Antarctic regions. All five loci were strongly polymorphic, with H O > 0.6 and Na > 7, and paternity exclusion probabilities were high (PE > 0.99), indicating the potential utility of these loci in paternity/maternity exclusion analyses of Patagonian toothfish. <![CDATA[<b>A reanalysis of the Chilean ocean circulation</b>: <b>preliminary results for the region between 20°S to 40°S</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100019&lng=en&nrm=iso&tlng=en The development and initial results from a reanalysis, or best estimate, of the historical state of central Chile's coastal ocean are presented. The Chilean Ocean State Estimate (COSE) covers the western coast of South America southwards of 20°S and for the period 1993 to 2012. The reanalysis is being performed using the 4DVAR driver of the Regional Ocean Modeling System (ROMS). The ROMS solution is constrained to reconcile satellite sea surface temperature and altimetry data with prior estimates of the initial state and boundary conditions derived from the HYCOM (Hybrid Coordinate Ocean Model) global reanalysis. Here we present preliminary results from COSE for central Chile and the year 2008. The regional reanalysis reduces the model-observations mismatch of the global HYCOM solution by 38 and 27%, for sea surface temperature and height respectively, and corrects a spurious on-shore surface current present in the HYCOM reanalysis. Inspection of the assimilation increments suggests that ROMS simulations forced by satellite winds overestimate coastal upwelling. <![CDATA[<b>New record of <i>Pherecardia striata</i> (Polychaeta: Amphinomidae) from Easter Island, Chile</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100020&lng=en&nrm=iso&tlng=en The polychaete amphinomid Pherecardia striata (Kingberg, 1857) is newly reported from the littoral off Easter Island (27°10'S, 109°20'W). The specimens are smallest than those collected in other tropical islands of the Pacific Ocean. P. striata resulted to be the least abundant of the three species of Amphinomidae collected from Easter Island: Eurythoe complanata (Pallas, 1776) and Linopherus sp. (Kohn & Lloyd, 1973b). <![CDATA[<b>A new species of polychaete worm from Juan Fernández Archipelago, Chile, <i>Scoloplos juanfernandezensis</i> n. sp. (Polychaeta: Orbiniidae)</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100021&lng=en&nrm=iso&tlng=en A new species of Orbiniidae, Scoloplos juanfernandezensis n. sp. from the Robinson Crusoe Island (33°37'S, 78°51'W), Juan Fernández Archipelago, Chile, is described. The samples were collected by means of SCUBA from depths between 4 and 10 m, between the years 2008 and 2012. This is the first record of the family Orbiniidae for the Juan Fernández Archipelago. The new species is principally characterized by the dichotomously branched branchiae in the mid-posterior chaetigers with 2 to 4 terminal filaments, thoracic neuropodial hooks hooded, neuropodial acicula embedded with straight distal end, emergence of the first branchiae between chaetigers 20-28, but starting not always occurs on both sides of the segment at a time, the absence of subpodials papillae and the morphology of the parapodia. Scoloplos juanfernandezensis most closely resembles Scoloplos cylindrifer Ehlers, 1905, from New Zealand and Australia and Leodamas latum (Chamberlin, 1919) from Pacific side of Panamá. <![CDATA[<b>Induction of triploidy in <i>Rhamdia quelen</i> (Siluriformes, Heptapteridae) by double-temperature shock</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100022&lng=en&nrm=iso&tlng=en This study evaluated sequential double-temperature shock (heat and cold) to induce triploidy in Rhamdia quelen. Fertilized eggs were heat shocked at 37, 39 and 41°C at 2 min post-fertilization and then cold shocked at 1°C for 20 min. Intact eggs were used as controls. Egg viability in control groups was higher (65.5 ± 37.0%) than that at 37°C (58.2 ± 37.7%), 39°C (1.8 ± 0.3%) and 41°C (0%). The survival of control hatchery (64.6 ± 36.8%) was higher compared to treatments at 37°C (24.4 ± 15.5%) and 39°C (0.6 ± 0.07%). Triploid percentages were 98.5% at 37°C and 100% at 39°C. Therefore, while double-temperature shock induced 100% triploidy in R. quelen, it also significantly decreased embryo survival and increased the deformity larvae. <![CDATA[<b>Evaluating quality of Nile tilapia (<i>Oreochromis niloticus</i>) eggs and juveniles from different commercial hatcheries</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100023&lng=en&nrm=iso&tlng=en Our objective was to assess the quality of eggs and juvenile of Nile tilapia (Oreochromis niloticus) from broodstock of three commercial hatcheries (Hl, H2, and H3). Larval weight was significantly higher for H2 and H3 hatcheries (P < 0.05). After 45-day growth, weight of juveniles of H2 was higher, while specific growth rate was significantly higher for H1 and H2 (P < 0.05). After the ammonia stress test, no significant differences in mortality were found among larvae from the three hatcheries, although a positive relationship between carbohydrate content in eggs and juvenile mortality was observed (P < 0.05). After the salinity stress test, the lowest and highest mortality (P < 0.05) occurred respectively in tilapia larvae from the H1 (24.2%) and H3 (57.8%) hatcheries. We concluded that egg quality was not affected by tilapia broodstock from the three hatcheries studied, but differences were obtained for growth performance, carbohydrate content, and survival of juveniles when exposed to the salinity stress test. These three indexes should be considered as potential juvenile quality criteria for tilapia. <![CDATA[<b>Potential of sites in northern Cuba for developing an industry of the native mangrove oyster (<i>Crassostrea rhizophorae</i>)</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100024&lng=en&nrm=iso&tlng=en Mangrove oysters (Crassostrea rhizophorae) were collected and raised for seven months at four sites (Punta Pargo, Jorobado, Cañete, and Enfermería) around Bahía Sagua La Grande on the north coast of Cuba, to determine which site offered the best conditions for cultivation of this commercially important species. Monthly measurements of oyster height were taken on 30 oysters randomly collected from each study site. Only oysters raised at Punta Pargo and Enfermería reached the mean commercial size (>40 mm) within the study period; these oysters were significantly larger than oysters raised at Cañete and Jorobado. No significant differences in survival between the sites were observed. Punta Pargo and Enfermería showed the best potential for oyster farming in the Bahía de Sagua area. Despite human impact on runoff caused by damming of the adjacent river, water quality remains acceptable for oyster cultivation. With proper stock management and production of selected fast-growing oysters in hatcheries, oyster farming can become an important aquaculture industry in Cuba. <![CDATA[<b>Deep ventilation event during fall and winter 2015 in the Puyuhuapi Fjord (44.6°S)</b>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000100025&lng=en&nrm=iso&tlng=en The Puyuhuapi Fjord has previously been reported as one of the hypoxic fjords in Patagonia (dissolved oxygen -DO below 2 mL L-1). Hydrographic sampling between 1995-2015 confirmed hypoxia below 100 m depth, down to the bottom (250 m). A line of sensors at an oceanographic mooring in Puyuhuapi were deployed to continuously record the temporal-vertical behaviour of water column temperature and salinity from the surface down to ~120 m, from February to July 2015. A Multi-parameter water quality sonde was deployed at the bottom of the line, with a DO optical sensor. From February to mid-May, hypoxia was sustained (1.4-1.6 mL L-1). However, from May until the end of June, DO values increased (2.8 mL L-1), exceeding the hypoxia threshold. This was the first event of deep ventilation reported in a Patagonian fjord. During this time period, deep water temperatures increased by ~1.3°C, coinciding with the decreased in salinity from 33.6 to 32.8. The main cause of this event was attributed to the arrival of a new volume of mixed oceanic water into the Fjord, transported by Modified Subantartic Water, with warm temperatures and slightly higher DO values, given its origin in the surface layer of the outer region of the Patagonian fjords and channels.