Penobscot River Restoration Project Monitoring: Examining Ecosystem Response to Large-Scale Restoration

Recognized as a model for cooperative conservation, the Penobscot River Restoration Project (PRRP) is an innovative, ecosystem-scale restoration project to restore self-sustaining populations of sea-run fish at all-time low populations by increasing connectivity in Maine’s largest river system through strategic removal of multiple barriers. The completed project provides 11 species of native diadromous fishes with significantly improved access to thousands of kilometers of freshwater habitat (including designated critical habitat for endangered Atlantic salmon) while also rebalancing hydropower. The Project provided a unique opportunity to initiate a comprehensive monitoring program to document baseline conditions of the Penobscot River ecosystem using before-after methodology.  With parameters in geomorphology, water quality, fish community, fish passage, fish migration and habitat use, wetlands and nutrient transfer, this program will provide an objective basis for evaluating ecosystem response. Early results show patterns emerging in four ecological focus areas: fish community, fish passage, physical habitat, and biological habitat.  We present baseline conditions prior to project implementation and explore these patterns in the context of ongoing and future restoration opportunities for sea-run fish throughout the Penobscot River system and Gulf of Maine.