Chapter 19: Coldwater Rivers
Darin G. Simpkins and Jessica L. Mistak
Coldwater rivers are large streams that are most often sampled from a boat or raft and are occupied by coldwater species such as salmonids. Many coldwater rivers have been modified as a result of water storage and dam-regulated flows. Nevertheless, fisheries management for coldwater rivers should not be considered independent to that of coldwater streams. Many coldwater species have fluvial life histories that require connections between streams and rivers to accommodate migratory behaviors, growth, and survival of specific life stages. Physical and biological processes in cold headwater streams affect those in coldwater rivers, which, in turn, structure fish assemblages. Consequently, fisheries managers of coldwater rivers must establish goals and objectives relative to specific abiotic and biotic attributes of rivers, as well as to life history requirements of fishes and ecological processes and management practices within entire coldwater drainages.
Fisheries management for coldwater streams and rivers has focused predominantly on salmonids owing to their economic importance in North America. Forty-seven of 50 states manage recreational salmonid fisheries (Epifanio 2000). In 2006, approximately 6.8 million anglers in the USA fished for salmonids over 76 million days in streams and rivers, which represented 27% of all anglers and 18% of all days fished (USDI 2007). The average freshwater angler spent US$460 on travel, food, lodging, equipment, and licenses. In 2005, approximately 3.2 million Canadians fished for salmonids over 43 million days in streams and rivers, spending Can$2.5 billion (DFO 2007). Thus, salmonids in coldwater streams and rivers support important recreational fisheries and generate substantial revenues.
Historically, management of coldwater rivers focused on stocking native or nonnative salmonids, manipulating flows and habitat to improve growth and survival of salmonids, and creating fishing opportunities. Most of these efforts have focused on small spatial scales, and little attention has been given to the significance of connectivity among streams and rivers in a watershed. More recently, emphasis to conserve native fish assemblages in coldwater environments has evolved as knowledge has been gained about the effects of human disturbances on ecological interactions among species and processes that structure fish assemblages. The purpose of this chapter is to introduce management practices used to conserve, enhance, or create fisheries in coldwater rivers.