The 1983 Atlantic salmon (Salmo salar) run on the Magaguadavic River, New Brunswick, monitored at the St. George fishway, totaled 940 fish, 637 salmon and 303 grilse, nearly double the highest previous count three decades ago. Female salmon outnumbered males 3.3:1 while male grilse outnumbered females 2.5:1, with an overall ratio of 1.5:1 in favor of females. Repeat spawners comprised 14.3% of the run. Strays, marked by fin clips, accounted for 5.5% of the run. The bacterial pathogen Edwardsiella tarda was identified in 4 of 13 salmon mortalities necropsied. Eight rainbow trout Salmo gairdneri as well as several thousand alewives Alosa pseudoharengus also ascended the fishway. Downstream migrations of juvenile alewives through the fishway occurred in August and October coincidental to full moons. The need for fishway repairs and modifications to improve fish condition and passage efficiency was identified.