Dams, water diversions, reservoirs, stream crossings, and natural features can alter movements of anadromous and resident fishes and other species and can isolate sub-populations from each other. Habitat connectivity is defined for the purposes of this report as the set of lateral, longitudinal, and drainage network connections between mainstem rivers, reservoirs, and tributaries, that provide chemically and physically unobstructed routes to fulfill life history requirements of aquatic species, including access to intact refugia and opportunities for genetic exchange. Approaches are described below to identify project effects on fish movement, and to evaluate effects of the fragmentation of fish populations (e.g., gene flow).
 | 4.4.2 Underwater observations | Page 72 of 134 | 4.5.1 Genetic analysis |  |