Migration and apparent survival of post-spawning alewife (Alosa pseudoharengus) in Minas Basin, Bay of Fundy

Abstract The anadromous alewife is a commercially fished clupeid in Atlantic Canada, whose oceanic migration poorly understood. Migration of alewives presently investigated from the lower reaches Gaspereau River into Minas Basin, Bay Fundy. Seventy-five post-spawning adults were tagged on their downstream migration; within two days being tagged, most had left and 57 entered Southern Bight Basin. Thirty-one detected Passage average time tagging to final detection was 28 with standard deviation 11 days. None until day 20 after start tagging. After 20, residence timescale Basin only 8.8 95% CI 8.4–9.3 Fast tidal currents prevail much study area, travelled many large excursions Passage. Separation distances between pairs increased greatly indicating mixing over area. Offshore movement associated seasonal warming, moving down spatial temperature gradient deeper waters. Offshore, larger displacements widely dispersed through During transit River, 18 ± 2 lost corroborating evidence mortality for 4 these. By apparent ? 10 alewives. Individual observed make transits during migration, where they may become exposed in-stream turbines.