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The sedimentation of salmonid spawning gravels in the Hampshire Avon catchment, UK: implications for the dissolved oxygen content of intragravel water and embryo survival
Author(s) -
Heywood M. J. T.,
Walling D. E.
Publication year - 2006
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.6266
Subject(s) - sedimentation , sediment , environmental science , hydrology (agriculture) , water quality , drainage basin , ecology , geology , biology , geomorphology , geography , geotechnical engineering , cartography
The accumulation of sediment within salmonid redd gravels can have a detrimental impact on the development of salmonid embryos; therefore, redd sedimentation represents a potential limiting factor for salmonid reproduction. The links between redd sedimentation, the dissolved oxygen content of intragravel water and salmonid embryo survival within the upper and middle parts of the Hampshire Avon catchment in southern England are explored. Measurements of surface and intragravel water quality and redd properties were undertaken for artificial redds constructed at known spawning sites. Salmonid embryos were also planted into artificial redds adjacent to the monitoring equipment. The rate of sedimentation of the newly cleaned redd gravels demonstrated a non‐linear decrease over time, which is attributed to a particle‐size‐selective depositional process. The results of the study confirm that low embryo survival and low dissolved oxygen concentrations in intragravel water can be attributed to the accumulation of sediment within the redd gravels. This was found to produce a reduction in redd permeability, which limited the interchange of surface and intragravel water and, therefore, the supply of dissolved oxygen to the intragravel environment. In view of the diminished status of salmonids within many of the UK's chalk rivers and streams, the results highlight the need for management initiatives aimed at reducing redd sedimentation and thereby optimizing salmonid embryo incubation success. Copyright © 2006 John Wiley & Sons, Ltd.