Spawning of the striped bass, Morone Saxatilis (Walbaum), in the Annapolis River, Nova Scotia

The spawning of the striped bass, Morone saxatilis (Walbaum) in the Annapolis River, Nova Scotia, was studied in 1976. Selected physical and chemical characteristics of the river were also examined. Bass egg collections indicated that spawning occurred from June 1-19. A total of 3463 eggs and three larvae were netted. Spawning was closely related to water temperatures on the spawning grounds: it was preceded by a rapid water temperature increase of 9°C during the week prior to the initial egg collection on June 1 (at 18°C). All significant spawning occurred at temperatures 218°C while rapid temperature drops to 15-16°C resulted in a temporary cessation of spawning. Peak spawning was from June 7-10 (65% of all eggs collected) when water temperatures were 19.0-24.4°C. Spawning occurred in freshwater (<0.1°4,salinity) within the first 15 km above the beginning of the salt wedge. Bass spawned along the 19 km section of the river between km 25 and 44. Most spawning occurred along the 9 km stretch between Bridgetown (km 29) and Paradise (km 38). Although extensive attempts were made to capture larvae and juveniles after the spawning season none were collected. Recruitment in 1976 was thus thought to have been very low or nil. Possible causes of the failure of recruitment are discussed.