Topic
Itata
About: Itata is a research topic. Over the lifetime, 17 publications have been published within this topic receiving 157 citations.
Papers
TL;DR: According to the reproductive states analysis in different periods of the year, populations inhabiting canal environments reproduce synchronically with those of the river, although these latter tend to show a slight delay in the reproductive activity.
Abstract: Trophic ecology and reproductive aspects of Trichomycterus areolatus (Pisces, Trichomycteridae) in irrigation canal environments. Twelve of the sixteen species of fishes present in the Itata river basin enter the irrigation canals at least once a year, constituting a habitat that is frequently utilized by the native fish assemblages. However, only Trichomycterus areolatus, a native siluriform, is found in great number throughout the entire year, being the dominant species of such artificial environments. Among the factors that could explain the relative success of T. areolatus are its benthonic habits, adaptation to rithral habitat, an offer of trophic resources that is in line with its feeding habits, and a lower abundance of predators in the canals. In this study, the trophic ecology of this species in 174 individuals inhabiting the Itata river (Octava Region, Chile) and 231 from irrigation canals that arise from this river are analyzed and compared. In addition, the length-weight relationship and seasonal frequencies of reproductive status are analyzed, with the purpose of inferring on the status of these populations and their possible condition of resident in these canals. In canals, its diet includes a greater number of different taxa as well as total number of preys consumed in comparison with the river populations, including items of greater biomass, such as lumbriculides. The selectivity analysis showed that T. areolatus prefer prey items like Chironomidae, Baetidae, Elmidae, Plecoptera and Hyallela. Although both the river as well as canal populations show an isometric type growth, they reach greater body lengths and weights in the latter. According to the reproductive states analysis in different periods of the year, populations inhabiting canal environments reproduce synchronically with those of the river, although these latter tend to show a slight delay in the reproductive activity. Rev. Biol. Trop. 53(1-2): 195-210. Epub 2005 Jun 24.
42 citations
TL;DR: Results of the work established baseline metal concentrations in the sediments of the area and identified tendencies in the spatial and temporal distribution of the metals in these marine sediments, which were not measurably elevated above natural levels.
30 citations
TL;DR: In this paper, the authors analyzed three areas of the Itata river (rhithron riffles, rhitron pools, and potamon) and three irrigation canals at the outtake and about 500 m downstream are analyzed.
Abstract: Benthonic fauna and substrate in three areas of the Itata river (rhithron riffles, rhitron pools, and potamon) and three irrigation canals at the outtake and about 500 m downstream are analyzed. Benthonic fauna included 56 taxa; of these, 12 were exclusive of the river, 11 were only found in irrigation canals, and 33 were in both environments. The widest distributions were found among the Diptera (Heptagyia annulipes and Orthocladiinae), while Trichoptera (Smicridea chilensis) and Ephemeroptera (Baetidae) were more abundant in the river. The highest biomass contribution corresponded to Gastropoda (Chilina dombeyana) in irrigation canals and in the river, although there was also significant Tipulidae family (Diptera) larval biomass in the latter. Both specific richness and density were higher in the river, while biomass did not show significant statistical differences. The mineralogical composition of the bottom of the canals and the river was different, the former being soil of granitic origin, the latter being sediment of a fluviovolcanic origin. Finally, the canal bottoms showed a higher content of organic matter than in the river.
26 citations
TL;DR: This study evaluated the health of the Chilean flounder Paralichthys adspersus inhabiting the marine coastal area influenced by the Itata River, finding significant differences in epidermal irritation lesions between stages and sites and between sexes and sites.
Abstract: This study evaluated the health of the Chilean flounder Paralichthys adspersus inhabiting the marine coastal area influenced by the Itata River. Flounder were also sampled at two reference sites during the course of 1 year. The pathological examination was done following the ICES protocol: external and internal lesions, condition factor, hepatosomatic and spleen indexes, and number of erythrocytes, lymphocytes, and thrombocytes. The prevalence of fish with lesions differed significantly among sites. The flounder sampled in the Itata area were the most affected. The evaluation of the macroscopic lesions observed on the flounder caught in the Itata area revealed (1) seven different types of macroscopic lesions, (2) a high prevalence of epidermal irritation lesions, and (3) a normal K factor, hepatosomatic index, and blood cell count. Significant differences were found in epidermal irritation lesions between stages and sites and between sexes and sites. Juveniles and adults as well as males and females were affected. A seasonal analysis of the macroscopic lesions on the flounder caught in the Itata area showed significant differences for only the epidermal irritation lesions between the sampled seasons of the year; the flounder caught in winter 2006 had the highest prevalence (77%) of such lesions. These results are discussed in relation to the hydrographic conditions, the contents of inorganic, nutrient and other organic compounds in the water column, and the contents of organic compounds and metals in the sediments of the subtidal environment in the Itata area.
23 citations
TL;DR: In this paper, two sectors, Itata and Valdivia, which are located in the Chilean margin were analyzed by using seismic data with the main purpose to characterize the gas hydrate concentration.
Abstract: Two sectors, Itata and Valdivia, which are located in the Chilean margin were analysed by using seismic data with the main purpose to characterize the gas hydrate concentration. Strong lateral velocity variations are recognised, showing a maximum value in Valdivia offshore (2380 ms−1 above the BSR) and a minimum value in the Itata offshore (1380 m·s−1 below the BSR). In both of the sectors, the maximum hydrate concentration reaches 17% of total volume, while the maximum free gas concentration is located Valdivia offshore (0.6% of total volume) in correspondence of an uplift sector. In the Itata offshore, the geothermal gradient that is estimated is variable and ranges from 32 °C·km−1 to 87 °C·km−1, while in Valdivia offshore it is uniform and about 35 °C·km−1. When considering both sites, the highest hydrate concentration is located in the accretionary prism (Valdivia offshore) and highest free gas concentration is distributed upwards, which may be considered as a natural pathway for lateral fluid migration. The results that are presented here contribute to the global knowledge of the relationship between hydrate/free gas presence and tectonic features, such as faults and folds, and furnishes a piece of the regional hydrate potentiality Chile offshore.
22 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
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| 2021 | 1 |
| 2020 | 1 |
| 2019 | 2 |
| 2017 | 2 |
| 2012 | 3 |
| 2011 | 1 |