PARENT SESSION
Oral Session 9: Marine Ecology I: Management.
Presiding: D Policansky
Monday, August 2, 8:00 AM to 11:30 AM, Meeting Room C 120.
The ecological recovery of a globally rare, freshwater tidal ecosystem.
Lichter, John*,1, Grinvalsky, Julianna1, Pasakarnis, Timothy 1, Souther, Christina1, Squiers, Thomas 2, Todd, Charles3, 1 The Environmental Studies Program and Institute of Coastal Studies, Brunswick, Maine, USA2 The Department of Marine Resources, Augusta, Maine, USA3 The Department of Inland Fisheries and Wildlife, Bangor, Maine, 04401
ABSTRACT- Merrymeeting Bay is a large freshwater tidal ecosystem formed by the confluence of six rivers, 27 km inland from the Atlantic coast of Maine. Immense numbers of migrating waterfowl and anadromous fish as well as dozens of pairs of nesting bald eagles once utilized the ecosystem. However, 200 years of human commercial and industrial activities beginning with dam building and overfishing in the 18th century and culminating in severe industrial and municipal pollution in the 20th century fully degraded this vital ecosystem. By 1930, the anadromous fish runs had collapsed, and in 1975, the number of nesting bald eagles had dwindled to a single pair. Ironically, migrating waterfowl may have utilized Merrymeeting Bay in greater abundances during the era of maximum pollution as nutrient loading fertilized the growth of the emergent plant communities on which they forage. With implementation of the Clean Water Act of 1972, Merrymeeting Bay and its tributaries began a sustained recovery. Water quality improved rapidly once the inputs of raw industrial and municipal wastes ceased. Since the late 1980s, recruitment of juvenile fish has been re-established for several species of anadromous fish, and bald eagles have made a remarkable comeback. In spite of the significant improvement in water quality and the initial recovery of fish and eagle populations, the legacies of land clearance, dams, overfishing, and pollution continue to affect this vital ecosystem. Merrymeeting Bay is permanently shallower with reduced habitat diversity; its anadromous fish runs and waterfowl migrations are vestiges of their former abundances; and toxic substances remain in its sediments.
Key words: ecosystem degradation, bald eagles, historical ecology , anadromous fish