Southern Chile, trout and salmon country: invasion patterns and threats for native species

In order to evaluate the present distribution patterns of salmonids and their potential effects on native fish, we sampled 11 large lakes and 105 streams, encompassing a total of 13 main hydrographic watersheds of southern Chile (39° to 52°S). Overall, trout (Salmo trutta and Oncorhynchus mykiss) ac...

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Autores principales:	SOTO,DORIS, ARISMENDI,IVÁN, GONZÁLEZ,JORGE, SANZANA,JOSÉ, JARA,FERNANDO, JARA,CARLOS, GUZMAN,ERWIN, LARA,ANTONIO
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2006
Materias:	trout invasion galaxid fish salmon farming catchments characteristics
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2006000100009
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spelling	oai:scielo:S0716-078X20060001000092006-04-25Southern Chile, trout and salmon country: invasion patterns and threats for native speciesSOTO,DORISARISMENDI,IVÁNGONZÁLEZ,JORGESANZANA,JOSÉJARA,FERNANDOJARA,CARLOSGUZMAN,ERWINLARA,ANTONIO trout invasion galaxid fish salmon farming catchments characteristics In order to evaluate the present distribution patterns of salmonids and their potential effects on native fish, we sampled 11 large lakes and 105 streams, encompassing a total of 13 main hydrographic watersheds of southern Chile (39° to 52°S). Overall, trout (Salmo trutta and Oncorhynchus mykiss) accounted for more than 60 % of total fish abundance and more than 80 % of total biomass, while 40 % of the streams sampled did not have native fish. Salmon, introduced for aquaculture, such as O. kisutch, Salmo salar, and O. tshawytscha, were only present in lakes with salmon farming and did not seem to be reproducing naturally in affluent streams. We tested the effect of river geographic origin (Andes mountains, central valley, or Coastal range) on fish abundance and found that rainbow trout was more restricted to the Andean streams with higher water discharge, while brown trout was widely distributed and did not relate to any of several catchment attributes measured. The abundance of native fish was greater in lakes than in streams and the highest native fish biodiversity occurred in streams of the central valley. The most common native species were Galaxias maculatus, G. platei, Brachygalaxias bullocki, Aplochiton zebra and Basilichthys australis. Streams with higher conductivity, larger pool areas, more fine sediments, and low brown trout densities were more suitable for native fish. Thus, catchments with higher anthropogenic disturbance appeared as refuges for native species. Given the descriptive nature of our study we can only presume the negative impacts of trout and salmon on native fish; an effect which should be superimposed on biogeographical conditioning of present distribution. Yet based on the present abundance and distribution patterns of salmonids and native fish, negative effects are very likely. Conservation of native fish biodiversity in central valley streams, far from protected areas or national parks and fully exposed to human perturbations represents a great challenge. We propose to enhance conservation by exerting a stronger sport fishing pressure on trout in those streamsinfo:eu-repo/semantics/openAccessSociedad de Biología de ChileRevista chilena de historia natural v.79 n.1 20062006-03-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2006000100009en10.4067/S0716-078X2006000100009
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	trout invasion galaxid fish salmon farming catchments characteristics
spellingShingle	trout invasion galaxid fish salmon farming catchments characteristics SOTO,DORIS ARISMENDI,IVÁN GONZÁLEZ,JORGE SANZANA,JOSÉ JARA,FERNANDO JARA,CARLOS GUZMAN,ERWIN LARA,ANTONIO Southern Chile, trout and salmon country: invasion patterns and threats for native species
description	In order to evaluate the present distribution patterns of salmonids and their potential effects on native fish, we sampled 11 large lakes and 105 streams, encompassing a total of 13 main hydrographic watersheds of southern Chile (39° to 52°S). Overall, trout (Salmo trutta and Oncorhynchus mykiss) accounted for more than 60 % of total fish abundance and more than 80 % of total biomass, while 40 % of the streams sampled did not have native fish. Salmon, introduced for aquaculture, such as O. kisutch, Salmo salar, and O. tshawytscha, were only present in lakes with salmon farming and did not seem to be reproducing naturally in affluent streams. We tested the effect of river geographic origin (Andes mountains, central valley, or Coastal range) on fish abundance and found that rainbow trout was more restricted to the Andean streams with higher water discharge, while brown trout was widely distributed and did not relate to any of several catchment attributes measured. The abundance of native fish was greater in lakes than in streams and the highest native fish biodiversity occurred in streams of the central valley. The most common native species were Galaxias maculatus, G. platei, Brachygalaxias bullocki, Aplochiton zebra and Basilichthys australis. Streams with higher conductivity, larger pool areas, more fine sediments, and low brown trout densities were more suitable for native fish. Thus, catchments with higher anthropogenic disturbance appeared as refuges for native species. Given the descriptive nature of our study we can only presume the negative impacts of trout and salmon on native fish; an effect which should be superimposed on biogeographical conditioning of present distribution. Yet based on the present abundance and distribution patterns of salmonids and native fish, negative effects are very likely. Conservation of native fish biodiversity in central valley streams, far from protected areas or national parks and fully exposed to human perturbations represents a great challenge. We propose to enhance conservation by exerting a stronger sport fishing pressure on trout in those streams
author	SOTO,DORIS ARISMENDI,IVÁN GONZÁLEZ,JORGE SANZANA,JOSÉ JARA,FERNANDO JARA,CARLOS GUZMAN,ERWIN LARA,ANTONIO
author_facet	SOTO,DORIS ARISMENDI,IVÁN GONZÁLEZ,JORGE SANZANA,JOSÉ JARA,FERNANDO JARA,CARLOS GUZMAN,ERWIN LARA,ANTONIO
author_sort	SOTO,DORIS
title	Southern Chile, trout and salmon country: invasion patterns and threats for native species
title_short	Southern Chile, trout and salmon country: invasion patterns and threats for native species
title_full	Southern Chile, trout and salmon country: invasion patterns and threats for native species
title_fullStr	Southern Chile, trout and salmon country: invasion patterns and threats for native species
title_full_unstemmed	Southern Chile, trout and salmon country: invasion patterns and threats for native species
title_sort	southern chile, trout and salmon country: invasion patterns and threats for native species
publisher	Sociedad de Biología de Chile
publishDate	2006
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2006000100009
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Southern Chile, trout and salmon country: invasion patterns and threats for native species

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