Evaluating Alewife passage efficiency at a modified culvert on Robinson Brook, Sackville, New Brunswick, Canada
LE3 .A278 2020
Bachelor of Science
Alewife (Alosa pseudoharengus) are an anadromous species of herring that live in the Atlantic Ocean From South Carolina USA, North to Newfoundland Canada. Adult Alewife spend most of their life in the ocean and only return to freshwater lakes to spawn. Alewife hold ecological value as a marine and freshwater species when they migrate and bring marine derived nutrients in freshwater systems. Although there has been research conducted on various styles of fishways and their efficiency, there is little information about the effects of culverts on migration runs of Alewife. Culverts are typically not monitored in any capacity and often create a barrier that prevents Alewife from reaching their natal spawning grounds. This can have a negative impact on the ecosystems as they are prey and predator species. In this study I assessed the passage efficiency of a culvert that is located on Robinson Brook, as well as factors that contribute to the efficiency rate. 291 Alewife were tagged at Robinson brook Culvert to determine the passage efficiency. It was determined that only nine percent of Alewife were successful in ascending the culvert. There was also no significant size difference between the alewife that were detected at the downstream antenna and those that attempted to ascend the fishway indicating that size selectivity may not present at heavily obstructed fishways. The low success rate can be attributed to the design of the culvert. The smooth concrete bottom increases water velocity beyond the swimming abilities of the Alewife. The culvert also creates a vertical overhang that makes make difficult for Alewife to ascend the fishway.
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