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Changes in fish communities following recolonization of the Cedar River, WA, USA by Pacific salmon after 103 years of local extirpation
Author(s) -
Kiffney Peter M.,
Pess George R.,
Anderson Joseph H.,
Faulds P.,
Burton K.,
Riley Stephen C.
Publication year - 2009
Publication title -
river research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.679
H-Index - 94
eISSN - 1535-1467
pISSN - 1535-1459
DOI - 10.1002/rra.1174
Subject(s) - fish migration , biological dispersal , oncorhynchus , trout , rainbow trout , habitat , fishery , population density , population , range (aeronautics) , ecology , fish <actinopterygii> , abundance (ecology) , biology , geography , demography , materials science , sociology , composite material
Migration barriers are a major reason for species loss and population decline of freshwater organisms. Significant efforts have been made to remove or provide passage around these barriers; however, our understanding of the ecological effects of these efforts is minimal. Installation of a fish passage facility at the Landsburg Dam, WA, USA provided migratory fish access to habitat from which they had been excluded for over 100 years. Relying on voluntary recruitment, we examined the effectiveness of this facility in restoring coho ( Oncorhynchus kisutch ) salmon populations above the diversion, and whether reintroduction of native anadromous species affected the distribution and abundance of resident trout ( O. mykiss and O. clarki ). Before the ladder, late summer total salmonid (trout only) density increased with distance from the dam. This pattern was reversed after the ladder was opened, as total salmonid density (salmon + trout) approximately doubled in the three reaches closest to the dam. These changes were primarily due to the addition of coho, but small trout density also increased in lower reaches and decreased in upper reaches. A nearby source population, dispersal by adults and juveniles, low density of resident trout and high quality habitat above the barrier likely promoted rapid colonization of targeted species. Our results suggest that barrier removal creates an opportunity for migratory species to re‐establish populations leading to range expansion and potentially to increased population size. Copyright © 2008 John Wiley & Sons, Ltd.