Abstract
ABSTRACT Dams are considered an important source of modification upon the structure of aquatic communities and their reflexes are diverse on the fish fauna. Although there are several hydroelectric power plants in Brazil, the long-term effects on feeding activity of ichthyofauna are unknown. Thus, this study aimed to investigate the long-term effects of an old reservoir (fifty years) on the trophic dynamics of fish fauna. The diet of 20 fish species was analyzed, identifying 37 food items belonging to six trophic categories, which enable to create six trophic groups. The results found here suggests that throughout the creation of a reservoir, the trophic structure of the fish assemblages tend to reach trophic homeostasis, in which the fish community will be capable of exploring the most available food resources being maintained primarily by the items placed in the categories organic matter and fragments of fish and vegetal.
Highlights
Dams are considered an important source of modification upon the structure of aquatic communities and their reflexes are diverse on the fish fauna
The time required by fish community structure to achieve certain degree of stability after reservoir closure may vary widely, and there is no consensus about it (PetrereJunior, 1996)
The trophic structure of a reservoir is the reflection of the interaction between the quality/quantity of food available in the environment and the degree of morphological/behavioral constraints showed by the species, though this last is liable to ontogenetic variations (Gaspar Da Luz et al, 2001)
Summary
Dams are considered an important source of modification upon the structure of aquatic communities and their reflexes are diverse on the fish fauna. Hydrological disturbances arising from damming are determinants of reorganization of fish assemblages in the new environment In this way, the availability of food supplies, the plasticity of feeding strategies and pre-adaptive characteristic of trophic guilds to lacustrine conditions are considered key elements for the establishment and accommodation of the ichthyofauna in reservoirs (Piet, 1998; Rodrigues-Ruiz, 1998). It is possible to establish that the impacts involved in the early stages of impoundments are directly related to changes in primary productivity caused by the release of nutrients from the decomposition of submerged organic matter (Balon, 1973; Petrere-Junior, 1996) This phase was designated by Kimmel & Groeger (1986) as a trophic outbreak period in which it is observed that the fish assemblage shows an increase in the consumption of either terrestrial invertebrates (Albrecht & Caramaschi, 2003; Balassa et al, 2004) and terrestrial vegetation (Cassemiro, 2005). On the other hand, Monteiro et al (2009) observed that in a small reservoir there were not significant alterations in the fish feeding dynamics, with only some subtle changes related to an increase of aquatic insects and algae consumption
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
