Temporal and Spatial Spawning Behavior of Alewife and White Perch in a System with Restored Habitat Access

Understanding spatial movement and habitat preference is necessary for species management and habitat conservation. Spatial and temporal movements of two anadromous species, alewife and white perch, were investigated in the Carman’s River (NY) using acoustic and radio telemetry. The Carman’s river spans 15 km from Great South Bay to its headwaters; however, fish can only access 5 km upstream due to an impoundment. Acoustically tagged alewife (n=54) and white perch (n=33) were monitored for three spawning seasons between 2012 and 2014. Approximately 20% of the tagged alewife displayed an oscillating pattern between the impoundment and mouth of the river, residing for several weeks. Other individuals resided in the river for several days before exiting the system. White perch displayed a diel migration pattern, moving upstream nightly to spawn. Furthermore, a fish ladder for alewife was installed in 2008, reconnecting an additional 5 km of freshwater habitat upstream. Approximately 5% of radio tagged alewife (n=258) successfully used this passage and displayed various spatial preferences within the upstream habitat. Monitoring this reconnected habitat provides information on the efficacy of fish ladder restoration and potential alewife productivity.