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

In this paper we propose a checklist of 14 species of exotic seaweeds on the Chilean coast, and three species which, being native to the Chilean coast, have been introduced in areas outside their natural range. This list was compiled from previously published checklist, debugged the misidentified records, and incorporating new ones. The distribution of exotic seaweeds is not homogeneous along the coast, but it is concentrated in areas near ports and aquaculture centers. Most species display a fairly bounded distribution, and only four tend to invade (i.e., increase its range of distribution over time). However, considering that most introductions are recent (the last 60 years) and the positive relationship between amplitude of the distribution range and residence time of species on the Chilean coast, we suggest that some of these species may be in an expansion phase, which would explain its restricted distribution. This work not only updates the information related to exotic seaweed on the Chilean coast, but also allows us to understand the invasion process, through the analysis of the patterns described in these systems.

El presente trabajo describe protocolo sobre la aplicación del desinfectante Buffodine® y un mix de antibacterianos para obtener alevines axénicos de trucha arcoíris (Oncorhynchus mykiss). Este protocolo permitió obtener y mantener alevines axénicos de trucha por un período de 26 días. Este período permite aplicaciones como ensayos con organismos gnotobióticos, una herramienta fundamental en los estudios para el entendimiento de la interacción bacteria-hospedero o parásito-hospedero.

Larvae of the Amazon River prawn, Macrobrachium amazonicum, were reared from hatching through nine stages to the first juvenile instar, comparing four experimental conditions with two salinities (5, 10) and two different types of salt (artificial, natural). Larval biomass growth was measured in terms of changes in dry weight (W), contents of carbon and nitrogen (C, N), and proximate biochemical composition (lipid, protein); moreover, body size (carapace length, CL) was measured in first-stage juveniles. After passing through the non-feeding first larval stage, later stages showed an exponential increase in values of biomass per individual. Rates of increase differed significantly among treatments, showing generally lower growth in experiments with artificial vs. natural salt, and at 5 vs. 10. The same response pattern was found also in CL of early juvenile shrimps. Similar but mostly weaker effects were observed in the percentage C, N, lipid, and protein values (in % of W), and in the C:N mass ratio. Our data indicate that larval rearing of M. amazonicum is feasible with artificial salts and at lower than commonly used standard salinity (10). This makes the cultivation of this species feasible also in aquaculture facilities located at large distance from the coast, where a reduction of costs and logistic investments may compensate for reduced larval growth and production of smaller juveniles. However, these negative effects have to be taken into account in comparisons of growth data from different laboratories.

Combined effects of temperature (25, 30 and 35°C) and salinity (15, 25, 35 and 45 g L-1), on the body composition and energetic value in the juvenile spotted rose snapper (Lutjanus guttatus), were investigated over 90 days. Significant effects of temperature, salinity, and their interaction on body composition and energetic value were analyzed. Low temperatures (25°C) significantly reduced the protein and increase lipid content in the body. In a temperature of 30°C, the highest energetic value was recorded, and in the highest salinity (45 g L-1), the energetic value was reduced. The salinity of 15 has the highest growth, protein content, and energetic value. It was found that the optimal temperature-salinity combination for the best relationship of growth (3.8% d-1), protein (21.9%), and lipid (4.9%) content, and energetic value (2.61 kJ g-1) was at 30 to 32.0°C and salinity of 35 g L-1. The effect of temperature was directly proportional to the increase in protein and inversely with the content of lipids in the body; salinity has its main effect negatively on these parameters in the highest salinity (45 g L-1).

Vitellogenins (Vtg) are glycolipophosphoproteins synthesized by oviparous vertebrates as yolk proteins precursors. These proteins have been studied for their role in reproduction and in endocrine disruption. In this work, we report the first proteomic study towards the characterization of Vtg from Pseudoplatystoma fasciatum, Piaractus brachypomus and Colossoma macropomum. Male specimens of each of the three fish species were estradiol-induced (experimental) and non-induced (control). The initial Vtg characterization was made by 2D protein gel electrophoresis of both groups The identification of the high molecular weight spots, presumed to be Vtgs, was assessed by MALDI-TOF mass spectrometry analysis. A post-translational modification study was performed by differential staining of 2D gels in order to visualize phosphoproteins and glycoproteins. Plasma samples from the three species, induced with estrogen, showed three high molecular weight spots with variable isoelectric points. Post-translational modifications showed that Vtgs from P. brachypomus and C. macropomum presented a phosphorylated and glycosylated subunit, while the same subunit in P. fasciatum was only glycosylated. This characterization will help in the development of reliable immunoassays, which could be used for studies of endocrine disruption or for the improvement of artificial spawning, by uncovering the time of fish maturation or sex determination.

The density and population parameters of the sea cucumber Isostichopus badionotus from Sisal, Yucatan, Mexico were determined during the fishing season. Belt transects of 200 m2 were set in 10 sampling sites at two fishing areas. All organisms within the belt were counted and collected. In the harbor, 7,618 sea cucumbers were measured and weighed: the population parameters were determined using FISAT II. Mean densities of I. badionotus in April 2011, September 2011 and February 2012 were 0.84 ± 0.40, 0.51 ± 0.46, and 0.32 ± 0.17 ind m-2, respectively. Sea cucumber total length varied from 90 to 420 mm, with a uni-modal distribution. The growth parameters were: L∞ = 403 mm, K = 0.25, and to = -0.18, with an allometric growth (W = 2.81L1.781). The total mortality was 0.88, whereas natural mortality was 0.38, fish mortality was 0.50 and the exploitation rate 0.54. Even when sea cucumbers fishery in Sisal is recent and in development with a high density (5570 ind ha-1), it is necessary to establish management strategies to protect the resource, such as an annual catch quota, catching size (>280 mm length), monitoring of population density, and reproduction and larval distribution.

We report for the first time the presence of doratopsis stages of Planctoteuthis sp. 1 (Cephalopoda: Chiroteuthidae) in the Gulf of California, Mexico, including a description of the morphological characters obtained from three of the five best-preserved specimens. The specimens were obtained from zooplankton samples collected in oblique Bongo net tows during June 2014 in the southern Gulf of California, Mexico. Chromatophore patterns on the head, chambered brachial pillar, and buccal mass, plus the presence of a structure, possibly a photophore, at the base of the eyes covered by thick, golden reflective tissue are different from those of the doratopsis stages of Planctoteuthis danae and Planctoteuthis lippula known from the Pacific Ocean. These differences suggest Planctoteuthis sp. 1 belongs to Planctoteuthis oligobessa, the only other species known from the Pacific Ocean or an unknown species. Systematic sampling covering a poorly sampled entrance zone of the Gulf of California was important in the collection of the specimens.

Austral hake Merluccius australis sustain an important demersal fishery in South Pacific and Atlantic oceans. The main spawning and nursery areas are in the Chilean Patagonia, which is characterized by large inputs of freshwater from rivers and ice melting. The spatial distribution of larval austral hake M. australis was studied during spring, and the potential effects of oceanographic conditions (temperature, salinity, vertical stability and turbidity) on early life traits, derived from sagitta otolith microstructure analysis, size-at-age (SAR), individual larval growth (IGR) and bilateral asymmetry (FA6). Larval abundance ranged between 0.86 and 41.55 ind 1000 m-3 (median: 4.08 ind 1000 m-3) and population larval growth estimated by micro-increment counts of sagitta otoliths was 0.129 ± 0.010 mm d-1, with age varying from 4 to 24 days old. All three indicators derived from otolith analysis (SAR, IGR, and FA6) showed positive and significant correlations with vertical salinity gradients; IGR and FA6 were also positively correlated to Brunt-Väisälä frequency (vertical stability) and FA6 was correlated to turbidity. Therefore, larval M. australis were larger-at-age, grew faster and showed more asymmetry in areas with more influence of freshwater runoff in south Pacific Patagonia.

Channel catfish, Ictalurus punctatus, is one of the most important fish on Mexican aquaculture and despite its productive potential, there is very few information regarding the distribution of Ictalurus species in Mexican territory. Sequencing of Cytochrome Oxidase I gene has proved to be very useful for the identification of fish specimens and sub-products. In the present, we report the molecular identification of 93 feral, commercial and domestic catfish individuals. All domestic fish were positively identified as channel catfish. Commercial samples were identified as Ictalurus punctatus, Ictalurus lupus, and Ictalurus furcatus, providing evidence that catfish represents a generic label for separate fish species. We also report the presence of feral I. punctatus on eight novel locations within Mexican territory, I. lupus on three and I. furcatus in one. Thus, we propose that molecular identification by DNA barcoding represents a powerful tool in the study of catfish populations and sub-products.

Despite the high landings of elasmobranch in Peru, little is known about some aspects of their basic biology, including their trophic ecology. The present study aims to provide basic information regarding the isotopic niche and trophic interactions of four pelagic elasmobranchs of commercial importance in northern Peru (Alopias spp., Galeorhinus galeus, Sphyrna zygaena, and Mobula japanica). One hundred and twenty-four samples were collected from fishing activities between January and December 2015 and processed for stable isotopes analysis (δ 13C and δ 15N), using Bayesian statistics to describe their isotopic niche. Differences between species were assessed using PERMANOVA and PERMDISP, allowing testing length, sex, and latitude as covariates. These combined results suggest trophic redundancy among sharks. However, unique areas of no overlap in the SEAC of all species could evidence a broad niche with a low interaction between these sharks. M. japanica had no overlap with any shark species, which indicates a trophic niche that is distinct from other elasmobranch top predators. Increasing sample size and including temporal covariates should help define these isotopic niches better, either by merging or splitting the studied elasmobranchs into more specific groupings. Further complementary studies are required to better understand trophic interactions within the pelagic community ecosystems.