Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

The goal of this study was to demonstrate the feasibility of culturing the seahorse Hippocampus reidi in an organic integrated multi-trophic aquaculture farm that produces the oyster Crassostrea brasiliana and the shrimp Litopenaeus vannamei. Experiments were conducted to evaluate the effects stocking density and food (natural zooplankton, Artemia nauplii, or both) for the juvenile I, which are fish from 1 to 15 days after birth. Stocking density effect was studied on growth and survival of juveniles II from 30 days to commercial size in net cages. Survival of the juvenile I was not affected by stocking densities from 2 to 5 ind L-1 and was greater than 70% in all treatments. Seahorse length, however, was inversely related to stocking density. Both treatments with wild zooplankton promoted higher seahorse survival and growth than diet composed exclusively by Artemia sp. during the first 15 days of life. Juvenile II growth decreased with stocking density from 5 to 40 ind m-3 but survival was not affected by it. The total benefit and proportion of colored animals increased significantly with stocking density. The present study confirms the technical feasibility of organic multi-trophic seahorse production in net cages. Even at the highest density tested the seahorses grew well and could generate high profits.

El ecosistema antártico es una de las regiones del mundo más sensibles al cambio climático, y presenta amplia variabilidad ambiental que modifican los patrones espaciales y temporales de la estructura fitoplanctónica. Se estudió la comunidad del fitoplancton y su variabilidad espacial y temporal de la ensenada Mackellar-bahía Almirantazgo, Antártida, en los veranos australes de 2012 y 2013. Se hicieron muestreos de agua para fitoplancton y variables ambientales en 11 estaciones a tres profundidades (0, 10 y 20 m). La masa de Agua Superficial Antártica de la zona de estudio fue reconocida. La composición total del fitoplancton en la columna de agua incluyó 40 taxones de diatomeas, 6 taxones de dinoflagelados y varias especies de nanoflagelados (< 20 µm). Los nanoflagelados pertenecen a Prasinophyceae, Cryptophyta y Haptophyta. La alternancia entre diatomeas del microplancton (20-200 µm) y nanoflagelados (< 20 µm) fue evidente durante el período de estudio: en el verano 2012 el grupo de los nanoflagelados fue más abundante (86%), con especies de diatomeas del género Thalassiosira sp. (11%), y para el verano 2013 los nanoflagelados disminuyeron considerablemente (20%), la abundancia del fitoplancton estuvo dominada por diatomeas como Thalassiosira delicatula (36%), Pseudo-nitzschia grupo delicatissima (9%), Porosira glacialis (6%), y el dinoflagelado Gymnodinium sp. (19%). La densidad celular en el verano 2012 fue menor, en comparación con el verano 2013, donde ocurrió una floración de diatomeas. La diversidad del fitoplancton fue baja (< 1,97 bits⋅célula-1) en ambos veranos. Las principales diferencias fueron la dominancia de diatomeas del microplancton y nanoflagelados, las cuales probablemente fueron causadas por la disminución de la salinidad y el aumento de oxígeno superficial observado en la Antártida, producto del deshielo ocurrido durante los veranos 2012 y 2013.

Chihuil sea catfish Bagre panamensis is a fishing resource exploited throughout the year and without restrictions on the central coast of the Mexican Pacific. In order to properly manage the commercial fishery of some resource, it is important to know aspects of its biology such as reproduction. In the present study, the reproduction period was estimated through the gonadosomatic index (GSI), hepatosomatic index (HSI) and the condition factor of B. panamensis. Samples were obtained monthly between November 2015 and October 2016 of commercial fishing from San Blas area. A total of 346 specimens were collected, which 182 were females and 164 males. The sizes (total length and weight) found did not show differences between genders. Sex ratio was not different from 1:1 for the total of the samples. The weight-length relationship showed that both sexes presented a positive allometric growth type. According to the gonadosomatic (GSI) and hepatosomatic index (HSI), this specie has a breeding period per year, which runs from May to August. Based on these results, a management strategy for this fishery could be proposed in the southeastern Gulf of California.

The yolk is the main energy source for eggs and marine fish larvae. Temperature is a key factor in determining the efficiency of yolk conversion into body tissues, which can affect the size larvae at first feeding. In this work, was evaluate the effect of different temperatures on the consumption of the yolk sac and oil droplet by the spotted rose snapper, Lutjanus guttatus, in order to determine the adequate culture temperature during the first days after hatch. The fertilized eggs were placed in 20 L plastic tanks at different temperatures (22, 25, 28 and 31 °C) with three replicates per treatment. The time and percentage of hatching, larvae total length, consumption of yolk and oil droplet at 0, 24, 48 and 72 h after hatching (HDE) were determined. Eggs incubated at 22 °C did not hatch, while hatching time in eggs incubated at 31 °C decreased significantly. No differences were observed in hatching percentage between treatments of temperature. Larvae reared at 31 °C obtained the higher length value than those reared at 25° C at 0 and 24 HDE. The yolk and oil droplet were consumed faster by larvae reared at 31 °C at 0 and 24 HDE. Total mortality was registered for larvae reared at 25 and 31 °C at 48 and 72 HDE, respectively. The optimal temperature for egg incubation and newly-hatched L. guttatus larvae was 28 °C, which would favorably impel the consumption of energy reserves for its growth and survival.

On February 27, 2010, the south central coast of Chile (ca., 34-39°S) was affected by an earthquake magnitude Mw= 8,8, with the epicenter located offshore Cobquecura (ca., 36.29°S). This earthquake originated continental uplift on that coastal areas closer to the trench between the Nazca and South American tectonic plates (i.e., Peninsula de Arauco and Isla Santa María) and subsidence along coastal areas located further north of that (the coast of the Maule Region), as well as in continental zones ordered in a west - east axis. In this study we tested the hypothesis that independent of the taxonomic group, the rocky shore sessile benthic organisms can be used as indicators of continental uplift. The methodology involved measurements of heights upper of distributional bands above the low tide level at the coast affected by the earthquake. The results show that the calcareous crustose algae Lithothamnium sp., the mytilid bivalve Perumytilus purpuratus and the macroalgae Mazzaella laminarioides and Lessonia spicata, are benthonic useful organisms to describe continental uplift, due to the fact that their vertical distributions after the earthquake follow the coastal deformation observed in the field. This allow to suggest that in studies aimed to evaluate this tectonic processes, more than a single species must be used in order to gain a full view of that along gradients of continental deformation. This due to the fact that a significant number of the benthic species of the rocky shore do not have continuous distribution; thus, to use a single species may well result in conclusions with low level of generalizations.

The composition and species proportion of catch were analyzed in the industrial and artisanal purse seine fishery occurred in the north of Chile. Biological and fishing information obtained on board fishing vessels between 2004 and 2012 through the Monitoring Program of Pelagic Fisheries in North Zone of Chile were used in this study. 9639 fishing hauls were analyzed. Four catch profiles explained the 34.27% of variance. The catch profiles were mainly composed by anchovy Engraulis ringens, jack mackerel Trachurus murphyi and mackerel Scomber japonicus. Anchovy was the dominant species. Only one catch profile grouped non-target species. Using GLM, the influence of type of fleet, temporal variability (year, month and trimester of arrival), day period, geographic position, sea surface temperature, fishing zone and coast distance in the catch profiles composition were analyzed. The trimester of arrival, day period, fishing zone, coast distance and sea surface temperature were the variables with greater statistical influence on catch profiles. A low proportion of non-target species was observed, influenced mainly by the fishing zone and the period of the day.

The reproductive condition of the jumbo squid Dosidicus gigas is poorly understood in Chile, through an oceanic-coastal migratory pattern during maturity and spawning has been suggested. The aim of this study was to describe the jumbo squid reproductive condition at the coastal zone off south-central Chile. For this, 1,335 specimens were analyzed from January-December 2014 to estimate their macroscopic sexual maturity and gonadosomatic index (IGS). The sexual proportion showed deviations of 1:1 in all months with a high dominance of females in January. Significant differences were found in the IGS between sexes and months, while maturity stages were relatively constant along time. Most recorded squids were immature, and only two mature females were found, suggesting that spawning occurs in oceanic waters off Chile.

Anchovy (Engraulis ringens) population units were analyzed in three zones off the coast of Chile: 1: Arica-Iquique, 2: Coquimbo and 3: Talcahuano-Valdivia from samples obtaineds during the 2012 spawning season. We used 50 left sagittae otoliths from each zone to perform a morphometric analysis, which included basic measurements, shape indexes and contour analysis (elliptical Fourier analysis). A MANOVA and Tukey multiple comparison analyses, applied on basic measures and shape indexes showed significant differences between zone 3 and zones 1 and 2. A classification by Canonical Discriminant analysis of elliptical Fourier harmonics, indicated significant differences among zones. It is concluded, therefore, that otolith shape analysis could be used to discriminate population units of Engraulis ringens. Better results were achieved using elliptic Fourier coefficients than using only shape indices.

A comparative analysis and synthesis of the current state of biological and fisheries knowledge of Thyrsites atun in the southern hemisphere is presented. The snoek T. atun, is a pelagic fish of the Gempylidae family, it inhabits cold waters and is distributed in southern sectors of the Southern Hemisphere, where it shows an opportunistic feeding pattern on small pelagic prey. Snoek populations are found in South Africa (SA), Australia (AU) and New Zealand (NZ), but in Chile remains unknown the existence of population units. In Chile sampled fish range in age between 1 and 6 years and size at the first maturity as been estimated at 65.6 cm fork length (FL). The present study concludes that in Chile there is poor biological and fishery information of snoek in comparison to the other countries where this species is also a fishing resource.

An assessment of mercury (Hg) concentrations and nitrogen stable isotope (15N) was conducted in the food chain of the Atlantic spotted dolphin (Stenella frontalis), including phytoplankton, zooplankton, planktivorous fish and its major prey (predatory fish and a single species of cephalopod), that compose a tropical trophic chain of the Brazilian southeastern coast. Tissue concentrations of Hg in a voracious predator fish, the largehead hairtail (Trichiurus lepturus), one of the dolphin’s prey, were 9.8 times lower than median concentrations found in dolphin tissues. 15N values in predatory fish were found to be lower to those of its predator the spotted dolphin. Isotopic data suggested significant differences for 15N along the trophic chain, with the top predator (dolphin) exhibiting heavier value, followed by the voracious predator fish and the benthonic carnivorous fish, the whitemouth croaker (Micropogonias furnieri). Phytoplankton displayed the lightest 15N, followed by zooplankton and the planktophagous fish, the lebranche mullet (Mugil liza). This fish species and the cephalopod showed the lowest median Hg concentration. All links of the entire trophic chain presented trophic transfer of Hg with a biomagnification factor higher than 1. A significant relationship was found between the log Hg concentration and trophic level (TL) of all evaluated species, with a positive slope (= 0.87). The calculated trophic magnification factor (TMF= 7.44) indicates that Hg concentration increased per TL, and also that the entire coastal food chain from the South Atlantic Ocean presented a biomagnification power of Hg within a range previously reported for tropical coastal ecosystems.