Investigation of migratory behaviors and passage technologies for American eels Project Number: 09032, 09056 Initiated: 1995 Status: Ongoing; combined as 09056 Location: Northeastern US (field study) Recruitment of catadromous American eels (Anguilla rostrata) to freshwater in North America has been shown to be declining, although the causes are unknown. Passage facilities for upstream and downstream migrant eels are lacking at hundreds of hydroelectric and other dams along rivers and tributaries of the Atlantic coast, reducing recruitment of eels into upstream habitats. Provision for upstream passage of eels has been shown to enhance recruitment to historic habitats in upstream sections of river currently blocked by dams. Several aspects of eel passage are being investigated in this study, including development of prototypes for upstream passes, age, growth, and life history traits in upstream rearing habitats, downstream migratory behavior, and technologies to reduce turbine entrainment and mortality. These focus areas are critical for providing sound biological data, design criteria and evaluation of passage structures, and a basis for future eel mitigation efforts and enhancement of populations on a coastwide scale.