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  • Author or Editor: Carlos Esse x
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Abstract

The Andes mountains in northern Chile have numerous small permanent and intermittent streams that are poorly studied; among the most reported species are amphipods of the genus Hyalella, specifically H. fossamanchini and H. kochi. The aim of the present study was to do a first characterization of populations of both amphipod species in a small stream (Caspana, 23°S; 3200 m a.s.l.), that was visited in September 2022. The first results using a Kruskall-Wallis nonparametric test revealed that the abundances of both species and unidentified juveniles were not significantly different in a comparison of two sites, whereas a Mann-Wittney nonparametric U test gave similar results when each species and juveniles were compared between sites. The results of variance/mean ratio revealed the existence of an aggregated pattern, and a negative binomial distribution for all samples. The occurrence of an aggregated pattern and the consequent negative binomial distribution is a very frequent pattern for inland water invertebrates in Chilean rivers.

In: Animal Biology

Abstract

The deep-water rose shrimp, Parapenaeus longirostris (H. Lucas, 1846), is the most dominant shrimp species on the Algerian west coast. In that area, the diet of P. longirostris was studied between July 2020 and June 2021. This approach to the diet of the rose shrimp was based on analysis of the stomach contents and determination of the ingested prey. A seasonal sampling was carried out in the main fishing ports (Béni Saf, Bouzedjar, Oran and Mostaganem). The results obtained showed that the shrimp feed intensively in spring and increasingly less in winter and summer. Crustaceans, foraminiferans, polychaetes, and molluscs constituted the most frequent preys in the diet, with respective frequencies of 58.85, 55.95, 36.63 and 32.04%. Small microplancton and mesoplancton prey (radiolarians, copepods, and various larvae) were less important in the diet of P. longirostris. Fish and echinoderms constitute accidental prey, of which the frequency is less than 10%.

In: Crustaceana

Abstract

The intertidal invertebrate community on rocky shores in northern Chile is characterised by a high species richness resulting from the high productivity of this ecosystem. The present study aims to do the first characterisation of invertebrate communities on rocky shores in Antofagasta town and surroundings (23°S), using species co-occurrence and niche-sharing null models, analysis of similarities (ANOSIM) and nonmetric multidimensional scaling (NMDS). The null model results revealed that species associations are not structured, that the existing species do not have the same ecology, which would result in many repeated species by site, and that specificity in their ecological niches exists. The ANOSIM and NMDS revealed the absence of significant differences between sites with human intervention and without human intervention. The obtained results agree with the literature for northern and central Chilean and southern Peruvian rocky shores, and other coastal marine ecosystems with high productivity.

In: Animal Biology

Abstract

The Chilean north Patagonian lakes are characterized by their marked oligotrophic or oligomesotrophic status and low abundance of zooplankton species; many of the lakes with oligomesotrophic status are associated with human intervention due to towns on their shores. The aim of the present study was to determine the relations between spectral properties (LANDSAT OLI), chlorophyll and plankton abundances in two north Patagonian lakes: Villarrica, which has two towns on its shores, and Lake Caburgua, which has native forest on its shores. The results revealed that Lake Villarrica has high reflectance in the near infrared, red and green bands, high concentrations of chlorophyll a, the absence of mixotrophic protozoa, and a high abundance of bacterial and plankton, mainly phytoplankton (Chlophyceae and diatoms) and zooplankton. Lake Caburgua, on the other hand, has low reflectance in the same bands, and low chlorophyll concentrations, low bacterial and zooplankton abundances, with the exception of high mixotrophic ciliates and small phytoplankton, and Volvox colonies. The obtained results agree with limnological observations on both lakes, and observations agrees with similar observations of the spectral properties of glacial north Patagonian lakes and of the zooplankton community, and in this scenario, the use of remote-sensing techniques would be a good tool to predict the plankton community in Patagonian lakes.

In: Animal Biology

Abstract

Antofagasta Bay is characterized by a high primary productivity due to the presence of the cold Humboldt Stream that is associated with a high diversity in flora and fauna in the benthic and pelagial environments of the Chilean west coast. Nevertheless, due to the global climate changes, the existing biodiversity patterns change as well. The aim of the present study was to analyse Antofagasta Bay for determining the existence of patterns between optical properties of the water, and the phytoplankton and zooplankton. The results show that one site had high chlorophyll concentrations, high reflectance, a high abundance of the dinoflagellate genus Dinophysis, and a high abundance of copepodites, whereas five sites had low chlorophyll concentrations, a low reflectance value, low copepodite abundances, and high abundances of dinoflagellates of the genera Ceratium, Gymnodinium and Prorocentrum. These results are similar to earlier observations for the coastal waters along northern Chile.

In: Crustaceana

Abstract

This present paper presents an inventory of benthic Malacostraca in the Gulf of Oran. The softbottom crustacean fauna was studied between February 2021 and September 2021. Samples were collected from 8 coastal stations. The class Malacostraca was represented with 2 subclasses, Eumalacostraca and Phyllocarida. Sixty-one species and 290 individuals belonging to seven crustacean orders (Amphipoda, Decapoda, Isopoda, Tanaidacea, Mysida, Lophogastrida and Leptostraca) were identified. Amphipoda were represented with the highest number of species (36) followed by Decapoda (11) and Isopoda (6). Tanaidacea and Mysida were poorly represented, with 3 and 2 species, respectively. Lophogastrida and Leptostraca were both represented by only one species. Among the crustaceans encountered, Ampelisca was the most dominant genus. The present inventory indicates that the carcinological fauna in the Gulf of Oran is less diversified than it is in other zones that have been studied on the Algerian coast (Gulf of Arzew, Bay of Bou-Ismail, and Bay of Algiers).

In: Crustaceana

Abstract

Antofagasta Bay is characterized by having a high primary productivity due to the presence of the cold Humboldt Stream. However, due to the current global climate change, also the previously generated biodiversity patterns are changing. The aim of the present study was analysing Antofagasta Bay in order to determine the existence of correlations between optical, i.e., spectral, properties recorded through remote sensing on the one hand, and the presence of dinoflagellates and zooplankton, on the other. The studies were done during two periods, i.e., in February 2019 and February 2020. The results revealed the existence of three main groups of sites: a first group comprising sites sampled in February 2019, with high Band 3 and Band 4 reflectance, high chlorophyl values, and high abundances of Dinophysis and copepods; a second group combining four sites visited in February 2019, with high Gymnodinium and Ceratium, high reflectance in Band 1, Band 2, Band 5, Band 6 and Band 7, and low zooplankton abundance; and finally a third group encompassing all sites sampled in 2020, with high Prorocentrum abundance, and low zooplankton abundance, as well as low reflectance. A similar situation with regard to zooplankton and optical properties was earlier reported for Chilean Patagonian lakes.

In: Crustaceana

Abstract

The decapod fauna of Chile’s intertidal shores in inner seas south of 40°S has relatively low diversity because of the presence of low-salinity waters due to river inputs and glacial smelts; nevertheless it is possible that the same decapods species are found as on the northern and central Chilean coast. The aim of the present study was to determine the spatial distribution patterns of lower intertidal decapods on Pelluhuín beach, a small beach south of Puerto Montt, northern Patagonia. Data were obtained by counting individuals from random quadrants in intertidal zones; to the obtained data the variance/mean ratio was applied to determine if the specimens have a random, aggregate or uniform distribution, which are associated with Poisson, negative binomial or positive binomial distributions respectively. Among four of the species observed, a uniform distribution (positive binomial) was reported, and one had an aggregated pattern (negative binomial). The sites correspond to rocky shores in semi-urban zones, and in a protected zone. Our results on the interpretative probabilistic models of aggregated distribution patterns agree with previously reported observations of decapods on the rocky shores of Northern and Central Chile, specifically in interpretative probabilistic models.

In: Animal Biology

Abstract

Existing studies on central Chilean inland waters only mention records of decapods, but there are no ecological studies about decapods and other crustacean groups. The aim of the present study was a first characterization of inland water crustaceans in Claro River, a Mediterranean-climate river from Chile. The results of redundance analysis (RDA) revealed that the crab Aegla affinis inhabits waters of high pH and low temperature values, whereas amphipods of the genus Hyalella inhabit habitats with high pH, high temperatures, and low values of dissolved oxygen. Finally, ostracods (family Cyprididae), isopods (Heterias sp.) and the southern river crayfish (Samastacus spinifrons) inhabit water systems with moderate values of pH, temperature, dissolved oxygen, and conductivity. This paper represents the first ecological report for crustaceans of central Chilean inland waters, and the results appear to be similar to comparable descriptions for northern Patagonian rivers.

In: Crustaceana

Abstract

The tiger crab, Aegla concepcionensis, is a threatened endemic freshwater decapod of Chile, distributed throughout small areas of the Mediterranean region of Central Chile (37°30′-38°00′S). Its habitat includes streams and lakes with riparian areas dominated by native plants, with little or null human intervention. To our knowledge, the tiger crab’s distribution is limited and human stressors (e.g., water withdrawal, exotic tree plantations and climate change) have led to degradation of its habitat. Based on the presence of these stressors and the virtual lack of knowledge of its ecology, the tiger crab has been categorized as Endangered (EN). This study presents a preliminary description of the species’ ecology based on its abundance and its morphometrics, as well as on its feeding habits in Caburgua lake, South Central Chile. We established 16 sampling points, half of which in the shallow bathymetric stratum (0-10 m depth) of the lake itself, and half in the Lumaco stream, one of the lake’s tributaries. We used baited traps to capture specimens. A. concepcionensis appeared to be found in the lake’s shallow bathymetric stratum, but not in the stream. Individuals showed negative allometric growth, males were larger than females, and they showed scavenger feeding behaviour. Our findings provide useful information to help with tiger crab conservation, although more extensive surveys will be required to collect sufficient data for establishing a robust conservation program for the species in the study area.

In: Crustaceana