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Effects of Dewatering on Chinook Salmon Redds: Tolerance of Four Development Phases to One‐Time Dewatering
Author(s) -
Becker C. Dale,
Neitzel Duane A.,
Abernethy C. Scott
Publication year - 1983
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(1983)3<373:eodocs>2.0.co;2
Subject(s) - chinook wind , oncorhynchus , zoology , dewatering , biology , fishery , fish <actinopterygii> , geology , geotechnical engineering
Four intergravel development phases of chinook salmon Oncorhynchus tshawytscha were experimentally dewatered in artificial redds. The redds consisted of aquaria filled with a gravel mix and supplied with 4 liters of water per minute at 10 C. Cleavage eggs and embryos (the egg phases) and eleutheroembryos and pre‐emergent alevins (the alevin phases) were each dewatered once for a continuous period. Egg phases were considerably more tolerant than alevin phases. Cleavage eggs tolerated one‐time dewaterings up to 12 consecutive days (98% survival), the maximum exposure period. Embryos had similar tolerance when dewatered 12 consecutive days (92% survival), but survival declined to 64% and 53% when embryos were dewatered 16 and 20 consecutive days, respectively. Loss of embryos after the longer dewaterings was associated with premature hatch. In contrast, eleutheroembryos tolerated only a 6‐hour dewatering period (96% survival) and underwent high mortality when dewatered 48 consecutive hours. Pre‐emergent alevins underwent near total mortality when dewatered 6 consecutive hours. Loss of alevin phases was associated with development of functional gill structures.