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Effects of Suction Gold Dredging on Fish and Invertebrates in Two California Streams
Author(s) -
Harvey Bret C.
Publication year - 1986
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 - 10.1577/1548-8659(1986)6<401:eosgdo>2.0.co;2
Subject(s) - dredging , salmo , streams , environmental science , invertebrate , sucker , fishery , sculpin , riffle , chironomidae , hydrology (agriculture) , fish <actinopterygii> , ecology , habitat , biology , larva , geology , zoology , computer network , geotechnical engineering , computer science
Abstract I examined the impact of small suction dredges (hose diameter, <16 cm) on fish and invertebrates in two California streams (North Fork of the American River and Butte Creek) in a 2‐year study. I studied both the effect of one dredge (1980) and the effects of an average of six dredges in a 2‐km section of stream (1981). Ten replicate Surber samples per station were taken monthly to compare macroinvertebrate abundances at control and dredged stations before, during, and after dredging in both years. Dredging significantly affected some insect taxa when substrate was altered. A recolonization experiment showed that numerical recovery of insects at dredged sites was rapid. Mask‐and‐snorkel censuses and observations of tagged fish indicated that major changes in available habitat caused local decreases in fish density. Dredging affected riffle sculpins (Cottus gulosus) more severely than rainbow trout (Salmo gairdneri), probably because of differences in microhabitat requirements. Local turbidity increases below active dredging probably did not affect invertebrates and fish.