River Ecology and Restoration - River Dynamics and Integrated River Management - page 696

shows riparian trees and wood logs in the water that provide shade and shelter for aquatic wildlife in the
Jiuzhaigou Creek in the upper Jialing River basin, which attract many fish in the river. Artificial devices
may be fixed to the bed or banks to provide additional cover. They include log overhangs, overhanging
platforms, felled trees, which have been anchored in place, and riprap (Claire, 1980). These have been
demonstrated to be particularly effective at increasing the number of trout in a reach (White, 1975).

Fig. 10.50 Experiment of replacing substrate with gravel, stones, sand, and silt in the Juma River near Beijing

Fig. 10.51 Riparian trees and wood logs in the water provide shade and shelter for aquatic wildlife and attract many
fish in the Jiuzhaigou Creek in upper Jialing River basin (See color figure at the end of this topic)

Artificial “fish attractors” (a cover device made of brush, bundles of old tires) have been used and
extensively tested in North American reservoirs, but less attention has been paid to rivers and streams.
Wilbur (1978) found that materials used to construct the attractor determined which species exploited the
created habitat. Brush and attractors made from the branches of trees were reported to be somewhat more
successful in attracting fish than attractors constructed of other materials. Anecdotal evidence indicates
that the spacing and configuration of branches may play an important role in attracting fish, so some
consideration of plant species is needed when brush piles or tree reefs are used as cover in streams.