The development of fish passage research in a historical context

For centuries, humankind has constructed dams on rivers to control flooding, provide for irrigation and utilize potential energy for power, but generally dams had no or little provision for fish passage. Thus, they often blocked or impeded fish migrations. Empirical observations and “trial and error” approaches that characterized historical efforts to develop passage systems for upstream migrating fish often did not work. The first concerted efforts to develop scientifically based fishways for upstream migrant fish began in the early 1900s in Europe with field and laboratory testing of different fishway designs. These were followed by extensive efforts beginning in the 1940s in North America. Scientifically based testing of configurations for fishways for downstream migrant fish began in the 1950s. Nearly all early efforts were directed at salmonid species, with smaller efforts on shad. Recent species at risk legislation in the U.S.A., Canada, and Europe places renewed emphasis on fish passage for all migratory species, and efforts have also begun to develop successful passage strategies for migratory species in other countries worldwide. This has led to renewed efforts to develop effective passage systems and to try creative solutions using natural materials in addition to concrete or metal used in standard technical fishways. Regardless of the type of structures built, history has shown that the most effective means to develop successful installations has occurred when engineers and biologists worked together systematically to design passage structures based on the ability and willingness of fish to seek and accept the hydraulic conditions presented to them.