-Habitat management
-By the 1990s, management objectives for many freshwater fisheries in North America had shifted from optimizing commodity output to protecting habitat or preserving imperiled species.
-Overall, alteration of aquatic habitat (e.g., dam construction, flood control structures, dredging to facilitate water transportation, filling to create useable land, sediment and pollution runoff, acid rain, etc.) is one important cause of the tenuous status of many fish species. Thus, protecting fish habitat has become a prime focus of many fisheries management agencies.