Cooperative Fish and Wildlife Research Units Program: Maine
Education, Research and Technical Assistance for Managing Our Natural Resources

The ecological role of prominent migratory fish species is a poorly characterized natural history in the Penobscot River and surrounding area. Manipulation of this River through habitat impact and impoundments has resulted in a greatly reduced exchange of nutrients between inland and marine sources. Nutrient exchange is of interest as restoration of anadromous fish runs may depend, in part, on a continuous cycle of nutrient import from the ocean. The proposed study will probe the role of marine derived nutrients (MDN) in the Penobscot River watershed by i) modeling the exchange of nutrients in salmon streams ii) explicitly testing how increased nutrients affect young Atlantic salmon and iii) characterizing historic MDN incorporation in watershed ecosystems. Objective 1. Model the exchange of nutrients in salmon streams Task 1: Compile data on the composition of migratory and non migratory fishes presently and historically found in salmon streams of Maine Task 2: Based on life history and proximate composition, generate a general model of the timing and extent of nutrient fluxes Task 3: Use composition and timing data to generate a biologically realistic schedule for the import of nutrients into small streams in Maine (for Objective 2) Objective 2. Explicitly test how increased nutrients affect young Atlantic salmon Task 1: Identify up to 8 streams (adjacent if possible) in the Penobscot drainage. Criteria will be based on history of migratory fish populations, habitat quality and size. Task 2: Define and characterize stream reaches and habitat collecting baseline water quality and species composition data; � Low level water chemistry (Total and available N, P; C:N ratio). � Stable isotope ratios of terrestrial and aquatic macroinvertebrates, instream algae, and fish. � Species assemblages and indicators of biomass for aquatic inverts (drift) algae (glass plates) and fish. Task 3: Initiate salmon stocking establish monitoring of salmon growth for young of the year. � All streams will be stocked with Atlantic salmon fry (equal numbers into control and treatment sites) � Establish stream control (upstream) and nutrient enhancement treatment (downstream) sections would be identified. � Assess juvenile salmon response (measured in growth/productivity responses as well as changes in tissue stable isotope ratios) to presence and absence of nutrient enhancement.