Challenges for Diadromous Fishes in a Dynamic Global Environment

How Policy, Politics, and Science Shaped a 25-Year Conflict over Alewife in the St. Croix River, New Brunswick-Maine

Theodore V. Willis


Abstract.—Consensus-based research uses scientific inquiry as an unbiased tool to contrast opposing positions in resource conflicts. However, when applied inappropriately, science is more likely to polarize opposing parties. Opposing parties also may use a consensus-based research process to delay actions not in their interest. The recreational smallmouth bass (SMB) Micropterus dolomieu fishery in the St. Croix River, New Brunswick–Maine is an example of how consensus-based research failed to bring opposing sides in a natural resource conflict to a mutually agreeable resolution. Recreational fishing guides blamed high alewife Alosa pseudoharengus returns for the crash of a naturalized SMB fishery in the upper watershed and proposed an exclusion law in response. In 1995, Maine legislated that all fishways in the St. Croix River be closed to alewives, with a resulting decline from 2.6 million alewives in 1987 to 900 by 2002. Claims of insufficient data to describe alewife ecological impacts on SMB led to formation of a local, state, provincial, U.S., and Canadian stakeholders science committee charged with developing a study that would describe SMB and alewife interactions. The committee identified the question “has alewife presence contributed to poor SMB population performance” as of primary importance to moving forward to a resolution. To test this hypothesis, SMB condition and growth, and the diet habits and diet overlap of alewives and SMB, were used as indicators of competition. Results, presented here, indicate that growth did not decline in the presence of alewives, age-0 SMB condition did not decline when alewives were present, and diet overlap between the two species was low in three of four lakes examined. Thus, the available data did not indicate that alewives caused poor SMB population performance. The project results helped break down institutional barriers between Maine natural resource agencies. However, local recreational fishermen were not satisfied with the project process or results, claiming that their interests, as represented by the state freshwater fish and game agency, were not seriously considered. They opposed and nearly defeated a bill to reintroduce alewives to the St. Croix River in 2008, again citing insufficient data to justify the action.