Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river
A total of 1,816 eels were sampled in 1988, from seven sampling areas. Four areas were located in brackish water and the remaining three were located in freshwater reaches of the Tagus river basin. Eels were more abundant in the middle estuary and decreased both in the upstream and in the downstream...
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ftunivtecnical:oai:www.repository.utl.pt:10400.5/5598 2023-05-15T13:27:52+02:00 Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river Costa, José Lino Domingos, Isabel Assis, Carlos A. Almeida, Pedro R. Moreira, Francisco Feunten, Eric Costa, Maria José 2008 http://hdl.handle.net/10400.5/5598 eng eng Springer "Environmental Biology of Fishes". ISSN 0378-1909. 81 (2008) 421-434 0378-1909 http://hdl.handle.net/10400.5/5598 openAccess Tagus river brackish and freshwater population structure feeding and condition dam impacts article 2008 ftunivtecnical 2021-04-04T20:23:20Z A total of 1,816 eels were sampled in 1988, from seven sampling areas. Four areas were located in brackish water and the remaining three were located in freshwater reaches of the Tagus river basin. Eels were more abundant in the middle estuary and decreased both in the upstream and in the downstream directions, with a predominance of males in higher density areas. Smaller individuals preferred more peripheral areas, such as margins and upper reaches in the brackish water zone, and the tributaries of the freshwater habitats. It was assumed that this distribution pattern resulted from three main factors: (i) the dominance of larger specimens; (ii) the need to avoid predators and; (iii) the search for better trophic conditions. The condition of the individuals generally decreased toward the upper reaches, apparently due to a corresponding decrease in feeding intensity. The presence of the Belver dam in the main river, 158 km upstream from the sea, seemed to impose major alterations to the described patterns. The concentration of specimens below this impassable obstacle yielded a reduction in the proportion of females and a decrease in the condition and survival of the eels, contributing to a reduction in the spawning success of this population. Suggestions to diminish the effects of the dam, and to preserve the fishery are also presented Article in Journal/Newspaper Anguilla anguilla Technical University of Lisbon: UTL Repository |
institution |
Open Polar |
collection |
Technical University of Lisbon: UTL Repository |
op_collection_id |
ftunivtecnical |
language |
English |
topic |
Tagus river brackish and freshwater population structure feeding and condition dam impacts |
spellingShingle |
Tagus river brackish and freshwater population structure feeding and condition dam impacts Costa, José Lino Domingos, Isabel Assis, Carlos A. Almeida, Pedro R. Moreira, Francisco Feunten, Eric Costa, Maria José Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river |
topic_facet |
Tagus river brackish and freshwater population structure feeding and condition dam impacts |
description |
A total of 1,816 eels were sampled in 1988, from seven sampling areas. Four areas were located in brackish water and the remaining three were located in freshwater reaches of the Tagus river basin. Eels were more abundant in the middle estuary and decreased both in the upstream and in the downstream directions, with a predominance of males in higher density areas. Smaller individuals preferred more peripheral areas, such as margins and upper reaches in the brackish water zone, and the tributaries of the freshwater habitats. It was assumed that this distribution pattern resulted from three main factors: (i) the dominance of larger specimens; (ii) the need to avoid predators and; (iii) the search for better trophic conditions. The condition of the individuals generally decreased toward the upper reaches, apparently due to a corresponding decrease in feeding intensity. The presence of the Belver dam in the main river, 158 km upstream from the sea, seemed to impose major alterations to the described patterns. The concentration of specimens below this impassable obstacle yielded a reduction in the proportion of females and a decrease in the condition and survival of the eels, contributing to a reduction in the spawning success of this population. Suggestions to diminish the effects of the dam, and to preserve the fishery are also presented |
format |
Article in Journal/Newspaper |
author |
Costa, José Lino Domingos, Isabel Assis, Carlos A. Almeida, Pedro R. Moreira, Francisco Feunten, Eric Costa, Maria José |
author_facet |
Costa, José Lino Domingos, Isabel Assis, Carlos A. Almeida, Pedro R. Moreira, Francisco Feunten, Eric Costa, Maria José |
author_sort |
Costa, José Lino |
title |
Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river |
title_short |
Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river |
title_full |
Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river |
title_fullStr |
Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river |
title_full_unstemmed |
Comparative ecology of the European eel, Anguilla anguilla (L.1758), in a large Iberian river |
title_sort |
comparative ecology of the european eel, anguilla anguilla (l.1758), in a large iberian river |
publisher |
Springer |
publishDate |
2008 |
url |
http://hdl.handle.net/10400.5/5598 |
genre |
Anguilla anguilla |
genre_facet |
Anguilla anguilla |
op_relation |
"Environmental Biology of Fishes". ISSN 0378-1909. 81 (2008) 421-434 0378-1909 http://hdl.handle.net/10400.5/5598 |
op_rights |
openAccess |
_version_ |
1766400844689833984 |