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Use of Gabion Weirs to Improve Spawning Habitat for Pink Salmon in a Small Logged Watershed
Author(s) -
Klassen H. D.,
Northcote T. G.
Publication year - 1988
Publication title -
north american journal of fisheries management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.587
H-Index - 72
eISSN - 1548-8675
pISSN - 0275-5947
DOI - 10.1577/1548-8675(1988)008<0036:uogwti>2.3.co;2
Subject(s) - oncorhynchus , watershed , streams , hydrology (agriculture) , habitat , weir , environmental science , fishery , debris , ecology , biology , geography , geotechnical engineering , geology , fish <actinopterygii> , oceanography , cartography , computer network , machine learning , computer science
Tandem V‐shaped gabion weirs for improving spawning habitat for Pacific salmon Oncorhynchus spp. were installed to replace large organic debris at three sites in Sachs Creek, Queen Charlotte Islands, British Columbia. Intragravel conditions were compared between three gabion weir pairs and six nearby reference sites. Survival of eggs of pink salmon O. gorbuscha was compared between one gabion pair and two reference sites. The improvement in intragravel dissolved oxygen depression (surface – intragravel concentrations) after gabion installation (a decrease from 5.4 mg/L before to 2.5 mg/L after installation) was significant (P < 0.05) when compared to changes found at nearby reference sites. Intragravel permeability also improved significantly (P < 0.05) after gabion installation in the low‐gradient (1%) reaches of Sachs Creek (from 870 cm/h before to 2,400 cm/h after installation). Pink salmon egg survival calculated by two indices at one gabion site in its first year of operation did not differ significantly (P > 0.05) from survival at two nearby reference sites. Gabions appear to be useful tools for the restoration of damaged streams.