Many streams in Maine’s coastal watersheds once provided habitat for sea-run (or anadromous) fishes like Atlantic salmon and alewives, but populations of these fish have declined or disappeared as a result of centuries of dam construction and pollution. A growing number of small-scale dam removals are attempting to restore freshwater-marine linkages in Maine watersheds, but the effects on fish are not well-documented. Coghlan and partners are attempting to establish a scientifically-sound monitoring program documenting the effects of barrier removal and anadromous species recovery on freshwater habitat, communities, and ultimately ecosystem-level functions.
In June 2008, researchers discovered a small but seemingly healthy population of sea lamprey spawning in Sedgeunkedunk Stream, a tributary of the lower Penobscot River, that is currently the target of restoration efforts. As the timeline for dam removal accelerated, researchers asked Sea Grant for emergency funds to collect crucial pre-spawn and pre-dam removal data. The study will provide much-needed empirical information to characterize and predict effects of stream restoration on resident and anadromous fishes, which is the subject of a Sea Grant research project that was informed by this preliminary data collection (See R-10-03).