Fish and Angler Use of Instream Habitat Enhancement Structures In ‘Restored' Stream Reaches

Artificial instream habitat enhancement structures (HES) are a pervasive stream restoration tool. A common goal of such projects is a population-level response in the fish assemblage. However, previous research suggests that HES may simply attract and concentrate fish from adjacent habitats rather than increasing population abundances. To examine a potential consequence of concentrating fish, we hypothesized that anglers may target fish associated with HES more successfully if artificial structures also concentrate angling effort. To test our hypotheses, we assessed spatial patterns of: 1) habitat structure; 2) fish holding locations; and 3) fishing pressure (i.e., casting patterns) and success (i.e., fish caught) in southwestern Montana stream reaches with HES. Across all sites, anglers targeted obvious HES, creating hotspots of exploitation adjacent to artificial habitat. Artificial habitat structures obvious to anglers may therefore act as sinks for fish by focusing fishing pressure over likely fish holding areas. Perhaps more importantly, this research underscores the need for a more holistic framework for assessing the role of HES in the restoration of stream habitat and fisheries management.