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Effect of Different Levels of Fine‐Sediment Loading on the Escapement Success of Rainbow Trout Fry from Artificial Redds
Author(s) -
Fudge Thomas S.,
Wautier Kerry G.,
Evans Robert E.,
Palace Vince P.
Publication year - 2008
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/m07-084.1
Subject(s) - rainbow trout , sediment , zoology , escapement , incubation , environmental science , fishery , biology , hydrology (agriculture) , fish <actinopterygii> , geology , geotechnical engineering , paleontology , biochemistry
Increased sedimentation from logging operations can affect water flow over salmonid redds, potentially impairing embryonic development in incubating eggs and fry. Effects may result from reduced oxygen delivery or waste removal or from physical entrapment of fry by sediment cap formation. A system of artificial redds was used to examine the effects of varying loads of mixed fine sediments on the escapement success of rainbow trout Oncorhynchus mykiss fry. Replicates of 80 eyed rainbow trout eggs were seeded in redds loaded with low (11.8%), medium (21.2%), high (28.6%), or no (0%) additional fine sediments. Interstitial oxygen saturation was determined in each chamber throughout incubation and emergence. Total percent emergence, residual yolk sac remaining, prevalence of deformities, and condition factor were determined in emergent fry. Fry began to emerge at 507.6 degree‐days postfertilization, and overall emergence was more than 70% in all treatment levels. Emergence rate patterns approximated a normal distribution in all treatment groups except for the high‐sediment‐loaded redds. Emergence of fry from the high‐sediment‐load chambers was greater initially and exhibited a slower, more continuous pattern. The formation of a sediment cap in the redds with high‐sediment loading appears to have significantly altered the emergence pattern of developing fry. Mean oxygen saturation was more than 79% in all groups and was not correlated to sediment load. Residual yolk was not different among fry from any of the groups throughout the emergence period. Fry condition factor decreased significantly over the sampling period, but there were no statistically significant differences among treatments.