Fishway Efficiency and Passage Behaviour of Alewife in Three Fishways Near Amherst, NS

When migrating inland to spawn the anadromous alewife (Alosa pseudoharengus) often must pass man-made fishways. Despite the prevalence of fishways, passage efficiencies are still poorly understood; they can range widely depending on designs, location and environmental conditions. To quantify passage efficiency and provide design improvements for new fishway construction, 1200 migratory alewives were tagged with Passive Integrated Transponders (PIT) tags. Tagged alewives were tracked through three technical fishways located on the Tantramar Marsh, near Amherst Nova Scotia. Passage efficiencies ranged from 0 - 75% across fishway designs with Denil style fishways far out performing one of the pool and weir design. Successful fish were measured to be larger (weight and length) than unsuccessful fish and spent less time below fishways while making more attempts at passage. Tagging data also quantified migratory duration ranging from  1-4 weeks  and provided information on migrant survival that was measured to vary from 70-100% between the study sites .