Abstract
Recovery dynamics in a previously disturbed
streamwere investigated to determine the influence of a series
of remedial actions on stream recovery and to evaluate the
potential application of bioindicators as an environmental
management tool. A suite of bioindicators, representing five
different functional response groups, were measured annually
for a sentinel fish species over a 15 year period during which
a variety of remedial and pollution abatement actions were
implemented. Trends in biochemical, physiological, condition,
growth, bioenergetic, and nutritional responses demonstrated
that the health status of a sentinel fish species in the
disturbed stream approached that of fish in the reference
stream by the end of the study. Two major remedial actions,
dechlorination and water flow management, had large effects
on stream recovery resulting in an improvement in the bioenergetic,
disease, nutritional, and organ condition status of
the sentinel fish species. A subset of bioindicators responded
rather dramatically to temporal trends affecting all sites, but
some indicators showed little response to disturbance or to
restoration activities. In assessing recovery of aquatic systems,
application of appropriate integrative structural indices
along with a variety of sensitive functional bioindicators
should be used to understand the mechanistic basis of stress
and recovery and to reduce the risk of false positives.
Understanding the mechanistic processes involved between
stressors, stress responses of biota, and the recovery dynamics
of aquatic systems reduces the uncertainty involved in environmental
management and regulatory decisions resulting in
an increased ability to predict the consequences of restoration
and remedial actions for aquatic systems.