New Zealand Journal of Marine and Freshwater Research abstracts
Redd characteristics and implications for survival of Chinook salmon (Oncorhynchus tshawytscha) embryos in the Waitaki River, New Zealand
K. R. DEVERALL
127 Park Road
Upper Hurt, New Zealand
J. R. M. KELSO
Department of Fisheries and Oceans* Great Lakes Laboratory for Fisheries and Aquatic Sciences 1 Canal Drive Sault Ste. Marie, Ontario Canada P6A 6W4
G. D. JAMES
NIWA - Freshwater
National Institute of Water and Atmospheric Research Ltd
P. O. Box 8602, Riccarton Christchurch, New Zealand
Abstract
Chinook salmon
(Oncorhynchus tshawytscha) redd characteristics were measured at three locations in the glacially-sourced mainstem and two locations in small, primarily rainfed, tributaries of the lower Waitaki River. Mean redd size was 17.5 m
2; lengths of redds ranged from 2.4 to 10 m and their widths ranged from 1.2 to 9.5 m. Water depth (mean ± SD = 0.37 ± 0.09 m) and water velocity (mean 0.68 ± 0.27 m s"
1) were significantly different between two of the mainstem locations but this may have resulted from differences in site conditions rather than preference by salmon. Substrate permeability, water flow rate through the substrate (termed apparent velocity herein) and oxygen were high in all redds and any "stress" to early fish life stages would likely result from excessive permeabilities (> 55.0 m h"
1) and apparent velocities (> 0.15 m Ir
1) rather than inadequate water circulation in the substrate. Although salmon did not use all available spawning habitat,
in situ redd conditions generally favoured good development and high survival rates.
Keywords chinook salmon; spawning; redds; redd characteristics; substrate properties
New Zealand Journal of Marine and Freshwater Research, 1993: Vol. 27: The Royal Society of New Zealand 1993
Received 11 January 1993; accepted 10 August 1993
PDF file of entire paper: medium quality (559K); (scanned from paper original: notes about this process)
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