Scielo RSS <![CDATA[Latin american journal of aquatic research]]> http://www.scielo.cl/rss.php?pid=0718-560X20170004&lang=en vol. 45 num. 4 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[The storm of August 8, 2015 in the regions of Valparaíso and Coquimbo, Central Chile]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400622&lng=en&nrm=iso&tlng=en RESUMEN El temporal del 8 de Agosto de 2015 se caracterizó por la ocurrencia conjunta de condiciones meteo-oceanográficas que causaron la destrucción de infraestructura costera y edificaciones en varias localidades del litoral central de Chile. El oleaje extremo se sumó a rachas de vientos provenientes del noroeste y una mínima histórica de la presión atmosférica asociada al sistema frontal. La marea de origen astronómico -aun cuando no extrema- hizo su contribución para peraltar el nivel del mar sobre el cual las olas rompieron con violencia en el borde costero. Para estudiar el evento se procesaron: a) registros de 64 estaciones meteorológicas distribuidas en el sector costero de las regiones de Valparaíso y Coquimbo, b) registros de 6 estaciones mareográficas en Chile Central, c) pronósticos y registro de oleaje en aguas profundas, y d) un modelo de propagación de oleaje desde aguas profundas hacia los sectores más afectados de la región. A partir del análisis de estas variables se explican los daños observados en la infraestructura costera.<hr/>ABSTRACT A storm of August 8, 2015 was characterized by the joint occurrence of meteorological and oceanographic conditions that caused the destruction of coastal infrastructure and buildings in several localities of the central coast of Chile. The extreme swell was added to wind gusts coming from the northwest winds, and a historical minimum of atmospheric pressure. The tide of astronomical origin -although not extreme-, made its contribution to the sea level banking on which the waves broke violent on the coastal edge. In order to study the event, records of: a) 64 weather stations distributed in the coastal zone of Valparaiso and Coquimbo regions, b) six tide gauge stations, c) forecast and wave records in deep-waters, and d) a model of deep-water wave propagation towards the most affected sectors of the region, were processed. From the analysis of these variables, the observed damages in the coastal infrastructure are explained. <![CDATA[Uncertainty of wave extreme values in Chile]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400649&lng=en&nrm=iso&tlng=en RESUMEN La falta de mediciones de oleaje es una realidad presente a la hora de realizar diseños de ingeniería marítima en Chile. Eventos como las marejadas del 3 julio 2013 y 8 agosto 2015 que dejaron cuantiosos daños estructurales, evidenciaron la falta de una red continua y de largo plazo de monitoreo de oleaje a la hora de estimar la frecuencia de ocurrencia de estos eventos. Esto implica que, en la actualidad, se debe confiar en bases de datos de oleaje de modelos de re-análisis globales, cuya calidad es desconocida para este propósito. En esta contribución se caracteriza la incertidumbre en la estimación de la frecuencia de ocurrencia de eventos extremos de oleaje. Para esto se analizan valores extremos de distintas bases de datos de oleaje disponibles. La comparación entre los valores de retorno encontrados es significativa, alcanzándose diferencias del orden de cientos de años en la estimación del período de retorno de un determinado evento. La calidad de la información de estas bases de datos para valores extremos se evaluó comparando el 10% de los valores más altos de la estadística de la altura significativa espectral con mediciones satelitales en ocho zonas a lo largo de Chile. La incertidumbre en la altura significativa espectral de período de retorno de 50 años tiende a aumentar de norte a sur, con diferencias entre bases de datos de 2,3 a 6,7 m. Los estadígrafos utilizados en la comparación con mediciones satelitales, muestran en general, mejores ajustes en el norte que en el sur a excepción de R2. Las correlaciones encontradas son muy bajas, con valores de R2 cercanos a 0 para puntos en la zona norte y donde la mejor correlación la alcanza la base de datos IFREMER frente al Golfo Coronados con un R2 = 0,66. Los sesgos son en general negativos, indicando subestimaciones cercanas a 1 m para las alturas significativas mayores.<hr/>ABSTRACT The lack of wave measurements is a reality when making marine engineering designs in Chile. Recent extreme wave events such as 3 July 2013 and 8 August 2015, left considerable structural damage and put into evidence the need for a continuous and long-term wave monitoring programme in order to adequately estimate the frequency of occurrence of these events. Presently, the frequency analysis relies on global wave reanalysis databases of unknown quality for this purpose. This contribution attempts to quantify the uncertainty in the extreme waves frequency analysis. An extreme wave frequency analysis was carried out for different available wave databases. There are differences of the order of hundred years in the significant wave height return values for recent events. The quality of the information of these databases was evaluated by comparing them with the 10% highest values of the significant wave height measured by satellite in 8 areas along Chile. The uncertainty in the 50 year return period spectral significant wave heights tends to increase from north to south, with differences between databases ranging from 2.3 to 6.7 m. The parameters used in the comparison with satellite measurements show, in general, better model skills in the north than in the south except for the R2 parameter. Correlations are very low with values of R2 near 0 for points in the north. The best correlation is found for IFREMER database in front of Golfo Coronados with R2 = 0.66. Biases are generally negative indicating underestimates near 1 m for the highest significant wave heights. <![CDATA[Coastal settlements rehabilitation affected by the 2010 tsunami in Pelluhue County, Chile]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400659&lng=en&nrm=iso&tlng=en RESUMEN La Comuna de Pelluhue fue una de las más afectadas durante el terremoto y tsunami del 27 de febrero de 2010 en Chile central, registrando 47 fallecidos, el mayor número de muertes per-cápita del país. Este estudio se orienta a analizar la resiliencia de los centros urbanos de la comuna, desde sus principales instancias: preparación, resistencia, recuperación y adaptación. Los daños generados por el tsunami se estudian mediante un levantamiento in-situ, complementado con levantamientos efectuados en 2013 y 2015, consulta de percepción de seguridad y un análisis del impacto de los instrumentos de planificación territorial en la rehabilitación de los centros urbanos. De estos estudios se concluye que la comuna experimentó una rápida recuperación de infraestructura entre 2010 y 2012. Las modificaciones incorporadas en la ordenanza del Plan Regulador Comunal a finales de 2012 promovieron el uso de una nueva tipología estructural adaptada al riesgo de tsunami en la Zona Turística de Borde Costero (ZTBC-1). El uso de marcos estructurales de madera y hormigón en el primer piso, se adoptó en respuesta al bajo coeficiente de ocupación de suelo sugerido en la ordenanza del Plan Regulador Comunal para dicha zona, sin necesariamente cumplir con criterios de diseño estructural. En otras zonas ubicadas en el área inundada, no obstante, se reconstruyó sin adoptar criterios de adaptación. Aun cuando se implementó una consulta, que no tiene la representación adecuada de toda la población, el sondeo indica que el plan de emergencia implementado por ONEMI, por su parte, generó una mejor percepción de seguridad en las zonas de riesgo por parte de los residentes, pero los visitantes desconocen las medidas de evacuación vigentes.<hr/>ABSTRACT The Pelluhue country was one of the most affected during the earthquake and tsunami of February 27, 2010 in central Chile, with 47 deaths, the highest number of per-capita deaths in the country. This study is oriented to analyze the resilience of the urban centers of the commune, from its principal instances: preparation, resistance, recovery and adaptation. The damage generated by the tsunami is studied through an on-site survey, supplemented by surveys conducted in 2013 and 2015, a safety perception consultation and an analysis of the impact of territorial planning instruments in the rehabilitation of urban centers. From these studies it is concluded that the commune experienced a rapid infrastructure recovery between 2010 and 2012. The modifications incorporated in the ordinance of the Community Regulatory Plan at the end of 2012 promoted the use of a new structural typology adapted to the tsunami risk in the Coastal Tourist Zone (ZTBC-1). The use of wood and concrete structural frames on the first floor was adopted in response to the low coefficient of soil occupation suggested in the ordinance of the Community Regulatory Plan for that area, without necessarily complying with structural design criteria. However, in some other areas, within the flooded area, it was rebuilt without adopting adaptation criteria. Even when a consultation was implemented, which does not have adequate representation of the entire population, the survey indicates that the emergency plan implemented by ONEMI, in turn, generated a better perception of safety in the risk areas by residents, but visitors are unaware of the current evacuation measures. <![CDATA[Modelling climate change impacts on anchovy and sardine landings in northern Chile using ANNs]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400675&lng=en&nrm=iso&tlng=en ABSTRACT Artificial Neural Networks (ANN) are adjusted to predict monthly landings of anchovy (Engraulis ringens) and sardine (Sardinops sagax) in northern Chile (18°21'-24°00'S). Fishing effort (FE), landings and twelve environmental variables are considered from 1980 to 2012. External validation for the best models using all variables showed an R2 of 95% for anchovy and 99% for sardine, with an efficiency of 0.94 and 0.96, respectively. The models were simplified by considering only FE and sea surface temperature (SST) from NOAA satellites (SST-NOAA). Using these variables, very similar fits were achieved, comparing with the previous models, maintaining their predictive capacity. Downscaled SST for A2 climate change scenario (2015-2065) obtained by statistical regionalization from the Community Climate System Model (CCSM3) from National Center for Atmospheric Research (NCAR) and three FE scenarios (2010-2012 average, + 50% and −50%), were used as inputs for ANN simplified models. For A2 future climate change scenario (2015-2065) using 2010-2012 average FE as inputs, anchovy and sardine landings would increase 2.8% and 19.2% by 2065 respectively. With FE variations (-50%), sardine landings show the highest increase (22.6%) by 2065 when FE is decreased. <![CDATA[Effect of β-glucan dietary levels on immune response and hematology of channel catfish <em>Ictalurus punctatus</em> juveniles]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400690&lng=en&nrm=iso&tlng=en ABSTRACT Biological response modifiers such as pro and prebiotics have been recently used in aquaculture showing abilities as immunostimulants, enhancing resistance to different fungal, bacterial and parasitic pathogens and tolerance to environmental stress. This experiment evaluated three different concentrations (0.05, 0.1 and 0.5%) of β-1,3/1,6 glucans on nonspecific immune parameters of channel catfish Ictalurus punctatus. Results showed that intake supplementation with 0.05% of β-1,3/1,6 glucans provides a greater immunostimulation over the fourth treatment week. Significant higher differences (P &lt; 0.05) were obtained on parameters related to phagocytic activity on blood cells, also other assays showed more reactive cells to nitroblue tetrazolium (NbT) stain on spleen and head kidney analysis. We conclude that the use of 0.05% of β-1,3/1,6 glucans added to a commercial diet improves nonspecific immune system of channel catfish I. punctatus. <![CDATA[OsHV-1 and notifiable protozoa in healthy <em>Crassostrea corteziensis</em> cultured in two distant areas of the Gulf of California]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400699&lng=en&nrm=iso&tlng=en ABSTRACT Infectious diseases have been a major limiting factor for large scale production of oyster farming. Several factors have contributed to the emergence and spread of infectious diseases in all cultivation sites around the world. Therefore, the prevention and control of diseases has become a priority for the sustainability of global aquaculture. Crassostrea corteziensis is a native species that contributes to the Mexican Pacific oyster production and used in this study to assess seasonal simultaneous infective events between distant areas in the Gulf of California. The results of the molecular analysis showed a higher prevalence of Perkinsus marinus in the north area and Marteilia refringens in the south. OsHV-1 was only present in summer and autumn with low prevalence in the two areas. The histological analysis of the PCR-positive organisms presented alterations characteristic of infections. The presence of M. refringens in a new location on the Gulf of California suggests that this pathogen is already well established in the area and the dual presence of pathogens in C. corteziensis is reported for the first time. <![CDATA[Genetic population structure and evidence of genetic homogeneity in populations of the Argentinian silverside <em>Odontesthes bonariensis</em> (Teleostei: Atherinopsidae) inhabiting central and northwestern Argentina]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400708&lng=en&nrm=iso&tlng=en ABSTRACT The study of species in their native geographic ranges is key to understanding how human activity has influenced spatial fragmentation or species homogenization. The Argentinian silverside Odontesthes bonariensis, of interest for aquiculture and sport fishing, is a relevant subject of study. The species has been introduced in a number of countries and re-introduced in some areas of Argentina with unknown effects. The objectives of this study were to determine the population structure, genetic diversity (GD) and effective population sizes (Ne) of O. bonariensis in Argentina. Six microsatellite loci were amplified in individuals collected from four water bodies affected by commercial and sport fishing: Cabra Corral Reservoir (CC), Chascomús Lake (CH), Chasicó Lake (LCH) and the Río de la Plata (RLP). Three genetic groups were detected: one in CC, one in RLP and the last inhabiting CH and LCH. Interestingly, CH and LCH are located 768 km apart, but showed no difference in allele frequencies; suggesting the introduction of individuals from CH into LCH. The largest allele richness, GD and Ne were found in RLP indicating that the largest population of O. bonariensis may be found in this area. Current Ne were lower than historical Ne in all areas, suggesting a change in the GD over time. This study provides information on the genetic structure and genetic diversity of O. bonariensis across its native distribution and over time, demonstrating the first evidence of a possible genetic homogenization in this species probably linked to human activities. <![CDATA[Catalase, superoxide dismutase, glutathione peroxidase and oxygen radical absorbance capacity in the gut of juvenile pacu <em>Piaractus mesopotamicus</em> and dourado <em>Salminus brasiliensis</em> fed bovine first milk secretion]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400717&lng=en&nrm=iso&tlng=en ABSTRACT Besides the immunological benefits of colostrum consumption, this lacteal secretion has a great concentration of biological molecules that can affect gut physiology and fish healthy. This study evaluated the antioxidant potential in the gut of juvenile pacu, Piaractus mesopotamicus, and dourado, Salminus brasiliensis, fed twice a day with diets containing 0, 10 or 20% of lyophilized bovine colostrum (LBC). The whole medium and posterior intestine was collected after 30 or 60 experimental days and the activity of catalase, superoxide dismutase and glutathione peroxidase was determined as one international unit per milligram of protein, and the oxygen radical absorbance capacity as μM of equivalent Trolox per milligram of protein. Only the juvenile pacu were affected by the diet containing LBC (P &lt; 0.05). The juvenile fed 10% LBC showed higher oxygen absorbance capacity than the juveniles fed 20% LBC (P &lt; 0.05). Interaction between diet and period was observed to superoxide dismutase (SOD) activity (P &lt; 0.05), juvenile pacu fed 0% LBC and 10% LBC did not change enzyme activity at 30 and 60 days, whereas juvenile fed 20% LBC showed higher value at 60 days compared to 30 days (P &lt; 0.05). The present result reveal that the consumption of diet containing LBC improved SOD activity in the gut of juvenile pacu indicating a possible protective action of this lacteal secretion in an omnivorous fish. <![CDATA[Vertical distribution of suspended sediment in the mouth area of the Magdalena River, Colombia]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400724&lng=en&nrm=iso&tlng=en RESUMEN Se utilizaron mediciones verticales de velocidad y concentración de sedimentos en suspensión obtenidas en dos épocas climáticas en la desembocadura del Río Magdalena, Colombia, para estimar: 1) la velocidad de corte, tensión de corte y altura de rugosidad mediante la ley de Wall o ecuación logarítmica, 2) velocidad de caída del grano, mediante ajuste con las distribuciones de Rouse, ecuación modificada de Rouse y perfiles verticales de la concentración de sedimentos en suspensión, y 3) con los parámetros estimados se determinó el transporte de sedimentos de fondo con las formulaciones de Meyer-Peter &amp; Müller (1948), Nielsen (1992) y Ribberink (1998). A partir de los parámetros estimados, se obtuvo un número de Rouse significativamente &lt;1 (0,01-0,18), velocidad de caída del grano (0,08-3,15 mm s−1) mucho menor que la velocidad de corte (15-70 mm s−1) y altos valores en la tensión de corte (1,1 −5,8 Pa). Al respecto, se puede afirmar que en el Río Magdalena predomina el transporte de sedimentos en suspensión. Los valores del transporte de sedimentos de fondo, calculados con las tres formulaciones, presentaron tasas &lt;5% del transporte total de sedimentos. La formulación de Meyer-Peter &amp; Müller (1948) subestima el transporte de sedimento de fondo debido a las condiciones en las que se calibró originalmente, mientras que las formulaciones de Nielsen (1992) y Ribberink (1998), pueden generar mejores estimaciones, debido a que fueron calibradas originalmente con sedimento fino, similar al tipo de sedimento registrado en la zona de estudio.<hr/>ABSTRACT Vertical measurements of velocity and suspended sediment concentration obtained in two climatic seasons at the mouth of the Magdalena River, Colombia, were used to estimate 1) bed shear velocity, bed shear stress and the bed roughness length by Wall law, 2) the settling velocity, by fitting distributions Rouse and Rouse equation modified and vertical profiles of suspended sediment concentration, 3) bed load sediment transport parameter estimates were determined with the formulations of Meyer-Peter &amp; Müller (1948), Nielsen (1992), and Ribberink (1998). From the estimated parameters, a number of Rouse significantly less than one (0.01 to 0.18), a settling velocity (0.08-3.15 mm s−1) much less than bed shear velocity (15-70 mm s−1), and high values in shear stress (1.1-5.8 Pa) were obtained. It can be said therefore that in the River Magdalena predominates sediment transport in suspension. The values of bottom sediment transport calculated with the three formulations represent lower rates to 5% of total sediment transport. The formulation of Meyer-Peter &amp; Müller (1948) underestimate the transport of bottom sediment due to the conditions under which it was originally calibrated, while Nielsen (1992) and Ribberink (1998) formulations can generate better estimates, because they were originally calibrated with fine sediment, similar to the sediment type reported in the study area. <![CDATA[Spatial and temporal variation of the endoparasite community structure of intertidal fishes in central Chile: parasitological descriptors, species composition and nestedness]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400737&lng=en&nrm=iso&tlng=en RESUMEN La estructura comunitaria de parásitos en peces de Chile ha sido poco abordada a través del tiempo y el espacio, impidiendo conocer los patrones de variaciones espacio-temporales. En este trabajo se estudia si la comunidad de endoparásitos de tres peces del intermareal de Chile central difiere entre localidades y años de muestreo, mediante descriptores parasitológicos, composición de especies y anidamiento. Se recolectaron 954 peces de tres especies, Helcogrammoides chilensis, Gobiesox marmoratus y Scartichthys viridis en pozas intermareales ubicadas en lugares cercanos a las bahías de Valparaíso (~32°45'S, 33°30'S) y de Concepción (~36°28'S, 36°41'S), durante 2013 y 2014. Las comunidades parasitarias fueron analizadas y comparadas por especie de hospedero, entre los rangos espaciales (localidades) y temporales (años). Los resultados muestran diferencias no significativas en los descriptores de abundancia, riqueza y diversidad entre localidades en los tres hospederos. Sin embargo, se observaron diferencias de estos descriptores entre años en la Bahía de Valparaíso para H. chilensis y G. marmoratus. La similitud de la composición parasitaria fue baja en cada especie hospedera al comparar entre años y localidades. Las infracomunidades de endoparásitos de S. viridis presentaron un patrón anidado en el tiempo y el espacio, a diferencia de G. marmoratus que presentó un patrón azaroso. En consecuencia, las escalas espacio-temporales son factores influyentes en la estructura de la comunidad de endoparásitos, pero su influencia difiere entre los hospederos. La repetitividad parece estar asociada a la especie de pez y las características agregadas de las comunidades de sus parásitos. Estos resultados indican que otros factores, ambientales y/o ecológicos, pueden influir en su estructura comunitaria.<hr/>ABSTRACT The parasite community structure in fish species of Chile have scarcely been analysed through time and locations, making it difficult to understand the spatio-temporal variation patterns. In this study, we investigated whether the endoparasitic community of three intertidal fishes in central Chile exhibited spatial or temporal changes. We collected a total of 954 individuals of Helcogrammoides chilensis, Gobiesox marmoratus and Scartichthys viridis in the intertidal rocky zone in localities close to the bays of Valparaíso (~32°45'S, 33°30'S) and of Concepción (~36°28'S, 36°41'S), during in 2013 and 2014. We analized the endoparasite community for each host according to their numerical descriptors, species composition and nestedness, comparing these communities as a function of both space and time. The average richness, abundance and diversity of the parasite infracommunity did not exhibit significant difference between localities (Valparaíso vs Concepción) for any of the host species. Only the parasitological descriptors of H. chilensis and G. marmoratus showed significant difference between years for Valparaíso. Similarity of parasite composition of each host species was low between years and geographical localities. The endoparasite infracommunity of S. viridis exhibited a nestedness pattern over time and space, unlike G. marmoratus that showed a random pattern over time and space. We concluded that spatio-temporal scales seem to be important factors for endoparasite community organization, but they affect different host species differently. The repeatability seems to be associated with the host species biology and the aggregate characteristics of the parasitic communities. However, our results suggest that other factors, such as environmental and/or ecological features, could impact on the community structure of parasites. <![CDATA[Modelling fishery-induced impacts on the food web of the continental shelf off central-south Chile using a size-based network approach]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400748&lng=en&nrm=iso&tlng=en ABSTRACT The continental shelf off central-south Chile sustains highly productive fisheries. The sustainability of these resources is nevertheless in jeopardy since many of them are either overexploited or collapsed. Using an allometrically (size-based) parameterized model of the shelf s food web, we analyze the likely ecosystem effects of fishing in this system by measuring the response of several ecological indicators to changes in fishing pressure. Indicators performed as follows: i) insensitive (community biomass stability, clustering coefficient), ii) varying directly (number of species going "extinct") or inversely (Normalized biomass size spectra (NBSS) coefficient of determination), and iii) abrupt inverse change, but then insensitive beyond a threshold (Fishing in Balance (FiB) index, Mean Trophic Level of the Catch, NBSS slope, and total community biomass). The latter four indicators seem less informative for management once a fishery has developed. Simulations showed that fishing any single species affected several species through food web-mediated mechanisms, then making difficult to predict the effects of fishing on the abundance of target and non-target species. Therefore, conservation measures should not rely exclusively on reducing fishing mortality for a given target species, but also take into account the status of interacting species. <![CDATA[Comparison of gene expression patterns of key growth genes between different rate growths in zebrafish (<em>Danio rerio</em>) siblings]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400766&lng=en&nrm=iso&tlng=en ABSTRACT Variable individual growth rate is a phenomenon observed in fish cohorts that influences the aquaculture performance and fish cohort ecological viability. Our aim was to compare gene expression patterns of key growth genes in zebrafish larvae with different growth rate. The body length of sibling zebrafish larvae at 6 days post hatching (dph) was measured. The larvae were reared to 20 dph and measured again. Two body-length groups were clearly observed: 4 mm (small larvae) and 5-6 mm (large larvae). Total RNA was isolated from both groups. Growth hormone (gh), growth hormone receptor (ghr), insulin-like growth factor 1 (igf-1), insulin-like growth factor receptor (igf-1r a/b), insulin-like growth factor binding protein 1 (igfbp-1), thyroglobulin (tg), cholecystokinin (cck), and ghrelin were evaluated by quantitative polymerase chain reaction (qPCR). Glucokinase (gck) and igfbp-1 were included as a gene expression marker of larvae nutritional status. Two genes showed significant differences between the body length groups, igfbp-1 (P = 0.01) and igf-1r (P = 0.02). The igfbp-1 suggests than growth rate variability was associated with the larvae nutritional status and this condition affect the gene expression pattern of igf-1r. Therefore these genes are interesting genes markers for growth rate variabilities studies. <![CDATA[Reproductive biology of <em>Macrobrachium amazonicum</em> (Heller, 1862) (Decapoda: Palaemonidae) in a reservoir situated in Minas Gerais State, southeastern Brazil]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400776&lng=en&nrm=iso&tlng=en ABSTRACT The palaemonid shrimp Macrobrachium amazonicum is widely distributed in coastal rivers, estuaries and inland waters of South America. Despite this, little is known regarding its biology in the natural environment. Furthermore, this species is economically important because it is the main freshwater shrimp commercially exploited by artisanal fisheries in northern and northeastern Brazil, besides showing great potential for aquaculture. Considering this, the present study aimed to analyze aspects of the reproductive biology of M. amazonicum. A total of 251 females were analyzed, 102 of these being ovigerous. The carapace length ranged from 6.03 to 10.06 mm (average ± standard deviation: 7.52 ± 0.84 mm). Reproduction was continuous with a gradual increase from April to June 2012. No significant relationship between frequency of ovigerous females and environmental variables was observed. The fecundity showed a positive linear relation with the carapace length and the number of eggs varied from 33 to 389 (average ± standard deviation: 203 ± 78.06 eggs/female). A dominance of eggs at an early stage was observed in most months. There was an increase in the size/volume of eggs from early to late embryonic stage. Ovigerous females produced eggs at the same development stage, with the same size and volume regardless of their body size. The results demonstrated higher similarity of this population to other continental M. amazonicum populations than from estuarine ones, showing the environment influence in the life-history of individuals. <![CDATA[Reproductive biology and population traits of tadpole codling (<em>Salilota australis</em>) off Chilean southern austral zone: fishery management considerations]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400787&lng=en&nrm=iso&tlng=en RESUMEN En este estudio se estimó la época principal de desove y la proporción de ejemplares maduros por longitud durante el periodo 1984-2006 en la zona sur-austral de Chile. El análisis macroscópico de las gónadas y las variaciones del índice gonadosomático indican presencia de ejemplares maduros durante todo el año con un periodo importante de desove entre agosto y septiembre. Se identificaron diferencias significativas en los procesos de madurez y crecimiento somático entre sexos, con hembras que alcanzan mayor tamaño y peso corporal. Salilota australis se ha convertido progresivamente en una especie objetivo para la pesquería demersal austral chilena, con longitud media de captura superior a la longitud en la cual el 50% de los ejemplares se encuentran maduros y alta disponibilidad de hembras. Debido a la desconocida vulnerabilidad de S. australis a la explotación pesquera, la descripción de los parámetros de vida debe ser tarea prioritaria en los programas de monitoreo de esta especie.<hr/>ABSTRACT The spawning period and proportion of length at maturity during the period 1984-2006 were investigated in a population of tadpole codling (Salilota australis) off southern austral zone, Chile. Macroscopic aspects and gonadosomatic index variability indicate the presence of mature individuals across the year with an important spawning period between August and September. Significant differences between sexes were detected in such processes, as maturity schedule and somatic growth, particularly in females which grow larger than males. Progressively S. australis has become an important target species for the austral demersal fleet in Chile, showing both an average catch length greater than the length at 50% maturity (LM) and high female fishery availability. In relation with the unknown vulnerability to overfishing of Salilota australis, the life history parameter analysis must be a priority needs within the monitoring fishing frameworks. <![CDATA[Wind forcing of sea level variability in a tropical coral reef area in the western Gulf of Mexico]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400797&lng=en&nrm=iso&tlng=en ABSTRACT Sea level, water temperature, and wind stress data were obtained from the Western Gulf of Mexico to elucidate the relationship between sea level changes and meteorological variables in a tropical coral reef system. Sea level and water temperature data were measured with a series of acoustic Doppler current profilers anchored at a depth of approximately 13 m in the Veracruz Reef System. The barometric and wind stress data were obtained from an automatic coastal weather station. Principal Component Analysis was applied to the series to determine the relative influence of the different meteorological variables on sea level. The seasonal variability of sea level is evident in the year-long data (September 2008 to April 2010) with a thermal expansion during the summer. Barometric pressure was found to be the second strongest forcing mechanism of sea level variability and not the first one. Opposite to what would be expected in protected coastal areas where the wind forcing mechanism on sea level may not be as important. The local winds were the main forcing mechanism of the sea level variability from March to September, while the meridional winds were more important than local winds from October to February. <![CDATA[Tourism growth altering spinner dolphins’ area of occupation in Fernando de Noronha Archipelago, Brazil]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400807&lng=en&nrm=iso&tlng=en ABSTRACT The objective of this study was to record the occupation of spinner dolphins at the northeastern end of the Fernando de Noronha Archipelago -a new occupation area. Data indicates that the area of the Inter Islands is the one in which the spinner dolphins present a longer permanence, defining a new pattern of occupation, with an annual tendency to stay for longer periods in the region. This change of permanence area may be related to the increase of tourism in Fernando de Noronha. The study points to the area of the Inter Islands as crucial for the conservation of spinner dolphin habits in the Fernando de Noronha Archipelago. <![CDATA[Response of mangrove propagules to the presence of oil- and hydrocarbon-degrading bacteria during an experimental oil spill]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400814&lng=en&nrm=iso&tlng=en ABSTRACT The aim of this work was to investigate the effect of marine diesel oil on the development and survival of three different species of mangrove propagules with or without a hydrocarbon-degrading bacterial consortium and the possible use of propagules for the recovery of mangroves impacted by oil. The study was conducted in a greenhouse, near a mangrove from which we collected samples of sediments and propagules of Laguncularia racemosa, Avicennia schaueriana and Rhizophora mangle. The bacterial consortium comprised Bacillus spp., Rhizobium spp., Pseudomonas spp., Ochrobactrum spp. and Brevundimonas spp. After six months, L. racemosa and A. schaueriana only survived in control treatments and R. mangle showed the highest survival rates of the three species, indicating that different mangrove species do not respond uniformly to oil spills. Propagules of R. mangle are much more resistant and the hydrocarbon-degrading bacterial consortium we tested can be applied in the phytoremediation of pollutants. <![CDATA[First assessment of MODIS satellite ocean color products (OC3 and nFLH) in the Inner Sea of Chiloé, northern Patagonia]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400822&lng=en&nrm=iso&tlng=en ABSTRACT The use of remote sensing has allowed enormous progress in our understanding of biophysical processes worldwide. Despite their importance, the use of satellite bio-optical products is still limited due to optical complexity. In this study we assess the performance of the Moderate Resolution Imaging Spectroradiometer algorithm for chlorophyll-a (MODIS-OC3) and of normalized Fluorescence Line Height (nFLH), in inner waters of northern Chilean Patagonia (41°-45°S). Satellite data were evaluated using a compilation of in situ chlorophyll-a data collected by the CIMAR-FIORDOS program during 2003-2012. During austral spring MODIS-OC3 showed a significant relationship with in situ measurements (R2 = 0.2, P = 0.03, F = 5.33) in comparison with winter when the relationship was non-significant. In contrast, nFLH explained a significant fraction of observed variance of Chl-a during austral winter (R2 = 0.54, P = &lt;0.01, F = 10.68) and this relationship was not significant in spring. Our preliminary results offer an excellent chance to understand patterns of variability of the autotrophic biomass and physiological status in optically complex interior marine ecosystems. <![CDATA[Preliminary assessment of slow release implant model for immunosuppression in juvenile pacu (<em>Piaractus mesopotamicus</em>)]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400828&lng=en&nrm=iso&tlng=en ABSTRACT Prolonged stress hampers immune function and lessens disease resistance of fish, causing economic losses. Attention is thus been centered in the study of fish immunology. The main ‘in vivoʼ models used in immunological studies are: stimulation of immune response (by immunostimulant molecules); induction of inflammation; induction of immunosuppression by chronic stress; or administration of drugs. This trial aimed at evaluating existing protocols for immunosuppression by drugs in fish, adapted to slow release implants model, using hydrogenated vegetable fat (HVF), with the intention of set a controlled immunodeficiency state model for advanced studies. The implant model was not efficient in reducing the immune response in a controlled manner. Evidence of self, down-regulation in fish immune system was found in implanted fish, what should be further investigated using molecular tools. <![CDATA[New record and morphometry of the bluntnose sixgill shark Hexanchus griseus (Chondrichthyes: Hexanchidae) in Baja California Sur, Mexico]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400833&lng=en&nrm=iso&tlng=en ABSTRACT We report the first record and morphometry of a complete juvenile Hexanchus griseus female shark, caught in Punta Lobos, Baja California Sur, Mexico. The oceanographic conditions of the area, where the specimen was caught, coincide with the habitat previously described for this shark species, with low temperature, stable salinity and high hydrostatic pressure. There is an overall lack of information about H. griseus in Mexico, with only eight records of its presence in the Mexican Pacific. Moreover, none of these previous records provided detailed information on the morphometry of a whole bluntnose sixgill shark. Here, we present the morphometric measures of a complete individual caught in shallow waters. We expect this information to be useful for future comparisons of specimens caught in other coastal regions. <![CDATA[Bathymetric range extension of the Peruvian flounder <em>Etropus peruvianus</em> Hildebrand, 1946 in the Gulf of California, Mexico]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400837&lng=en&nrm=iso&tlng=en ABSTRACT From September 2004 to February 2005, 204 specimens of Etropus peruvianus were collected onboard exploratory fishing cruises in the eastern Gulf of California, caught in trawls at 276 m in depth. This finding exceeds the limit of vertical distribution (125 m) previously known for this species. Oceanographic conditions (such as temperature, salinity and dissolved oxygen), feeding and reproductive behavior determines the extension of the vertical distribution of E. peruvianus. <![CDATA[Shrimp trawling bycatch of ray <em>Hypanus americanus</em> (Elasmobranchii) in the southeastern region of Cuba]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400840&lng=en&nrm=iso&tlng=en RESUMEN La pesquería de camarón con red de arrastre es una de las que más contribuye a la generación de captura incidental debido a la baja selectividad que presenta este arte de pesca. En Cuba su uso está permitido en cuatro empresas pesqueras que operan en la región suroriental del país. El objetivo de este trabajo fue estimar las tallas, proporción de sexos y fecundidad de la raya Hypanus americanus en la pesca de arrastre de camarón y la posible relación con las regiones ecológicas. El estudio se realizó entre enero de 2015 y febrero de 2016, analizándose 300 ejemplares. Las capturas estuvieron constituidas por 61% de hembras y 39% de machos, con anchos de disco (AD) entre 21,5-135 cm y 20-137 cm respectivamente. Se identificaron 41 hembras grávidas con una fecundidad de 1 a 5 embriones, además se estableció una correlación entre el ancho del disco y el número de embriones. Este es el primer estudio que se realiza sobre el tema en Cuba, por lo que los resultados obtenidos son novedosos para el sector pesquero.<hr/>ABSTRACT Shrimp trawl fisheries have a high incidence of bycatch due to the low selectivity of the fishing gear. In Cuba shrimp trawling is permitted by four state fishing enterprises that operate in the south east region of the country. The objective of this work is to estimate sizes, proportion of sexes and fecundity of Hypanus americanus in the shrimp trawl fishery and its possible relation to designated fishing zones. The study was carried out between January 2015 and February 2016 with 300 specimens examined. The catches were 61% female and 39% male, with disc widths between 21.5-135 cm and 20-137 cm respectively. Forty-one pregnant females were identified with fecundity of 1 to 5 embryos; also a correlation between the disc width and the number of embryos was established. This is the first study that has been carried out on this topic in the country; therefore the results provide new information for the fishing region. <![CDATA[Oxidative stress and RNA/DNA ratio following longline capture in the silky shark <em>Carcharhinus falciformis</em> (Müller & Henle, 1839)]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400846&lng=en&nrm=iso&tlng=en ABSTRACT This study used transcriptomics tracers and measurements of oxidative stress to examine the effect of capture by longline on the silky shark Carcharhinus falciformis. From February 2010 to May 2012, C. falciformis individuals captured in the eastern Pacific Ocean were initially examined for sex, degree of maturity, and morphometric data. Samples were then taken from muscle tissue to determine RNA, DNA, and protein concentrations as well as RNA/DNA and protein/DNA ratios. The levels of three oxidative stress indicators [superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA)] were determined in muscle. The analysis of the 159 specimens (93 juveniles and 66 adults) showed low RNA/DNA ratios at the different stages of maturity. This basal level of transcriptomics capacity may have been caused by the physiological stress resulting from capture. In juveniles, the low RNA/DNA and protein/DNA ratios were associated with low levels of cellular damage related to oxidative stress, whereas in adults the level of cell damage due to oxidative stress was high, especially in older females. This pattern indicated decreased antioxidant response capacity with increasing age in elasmobranchs. <![CDATA[Coinfection of <em>Caligus lalandei</em> and <em>Benedenia seriolae</em> on the yellowtail kingfish <em>Seriola lalandi</em> farmed in a net cage in northern Chile]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400852&lng=en&nrm=iso&tlng=en ABSTRACT The yellowtail kingfish Seriola lalandi is one of the most important fish candidates for the diversification of aquaculture in Chile. Fish farmed experimentally in one floating cage on a site located in Northern Chile, between November 2013 and December 2015, were first detected with the sea lice Caligus lalandei from April 2014. The highest prevalence (100%) was reached in July 2014 and the highest abundance in June 2014 (4.3 lice/fish). The monogenean Benedenia seriolae was also recorded in the same stock of fish from July 2014, reaching the highest abundance of 30.8 parasite/fish and a prevalence of 100% in January 2015. When the abundance of B. seriolae increased, C. lalandei abundance decreased until it disappeared in January 2015, which could be attributed to the increase of the seawater temperature in the period of study. This is the first report of C. lalandei infecting S. lalandi reared in net cage in Chile. <![CDATA[Embryonic development stages description in <em>Gambusia puncticulata</em> (Pisces: Poeciliidae) from Almendares River, Cuba]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400858&lng=en&nrm=iso&tlng=en ABSTRACT This research's main goal is the description of the embryonic developmental stages of Gambusia puncticulata. It also provides an analysis of the embryonic mean developmental stage, and mean weight in relation to the mother's carcass weight. The fish were caught monthly from July 2006 to June 2007 throughout Almendares River, North of Havana, Cuba. The embryonic mean stage values (F4,600 = 14.79, P &lt; 0.001), and mean weight values (F4,395 = 7.09, P &lt; 0.001), increased with mother's size increment. This research describes, for the first time, seven embryonic developmental stages in G. puncticulata. The applied macroscopic classification of the embryos showed great consistency, due to the large number of examined specimens. The criteria used to define the stages are accurate, and allow to distinguish the stages easily, quickly and with high reliability. These criteria could be applied to other species of the Gambusia genus. <![CDATA[Shoalgrass <em>Halodule wrightii</em> () meadows in El Salvador: distribution and associated macroinvertebrates at the estuary complex of Bahía de Jiquilisco]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-560X2017000400864&lng=en&nrm=iso&tlng=en ABSTRACT Seagrasses are aquatic angiosperms that grow submerged in shallow marine and estuarine environments worldwide. Halodule wrightii is a circumtropically distributed seagrass species found primarily in the Atlantic Ocean, but also in parts of the Indian Ocean and eastern Pacific Ocean. Along the Pacific coast of Central America, large swaths of the reported distribution of H. wrightii are assumptions based on interpolation between known seagrass point locations, and despite confirmation of H. wrightii occurrence in Bahía de Jiquilisco in El Salvador, little is known about its distribution and associated species, which can hamper efforts to conserve this seagrass ecosystem. To address these gaps in data, we provide the first assessment of H. wrightii distribution and associated macroinvertebrate species in Bahía de Jiquilisco. We identified six areas where seagrasses occurred and two of these were selected for monitoring. At the two sampled areas, heterogeneous patches of H. wrightii covered 27.1 km2 with 22 associated macroinvertebrate species from three taxonomic groups in three phyla. We conclude by discussing local threats to H. wrightii, including implications for endangered hawksbill (Eretmochelys imbricata and green (Chelonia mydas agassizii) turtles that depend on these ecosystems, and describe opportunities for conservation in Bahía de Jiquilisco.