Steve Coghlan
5755 Nutting Hall, Room 240
University of Maine
Orono, ME 04469
207.581.2880
stephen.coghlan@umit.maine.edu

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. The lamprey built 47 nests covering 40% of the surface area of the streambed downstream of the soon-to-be-removed Mill Dam. A combination of substrate disturbance and apparent nutrient enrichment prompted Coghlan to ask the questions, “Do sea lamprey condition stream habitat to the benefit of other species, especially endangered Atlantic salmon?” and “How will barrier removal and subsequent range expansion of sea lamprey impact stream communities and anadromous fish migrations in Maine?” Although the effects of spawning runs of Pacific salmon on stream communities are well known, no such information exists for sea lamprey. As the timeline for the 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.

2-year project
Total: $5,000