Recruitment in Threatened Riverine Species of Nova Scotia: Atlantic Salmon (Salmo salar) and Brook Floater (Alasmidonta varicosa).

Abstract

Freshwater ecosystems are among the most threatened ecosystems globally, with unionids and salmonids experiencing severe declines. Conservation requires understanding recruitment and identifying where disruptions occur across life stages. This thesis examines recruitment in two freshwater species to inform conservation strategies. Chapter two used radio telemetry to assess Atlantic salmon spawning distribution in the Margaree River, Nova Scotia. Results indicated high residency in lower river reaches before spawning, with use of upper reaches occurring only in late fall (October–November). Chapter three investigated host relationships of brook floater mussels in the East St. Mary’s and Wallace rivers. PCR and sequencing of glochidia from fish gills identified lake chub as a host species in the St. Mary’s River. Additionally, a non-lethal method for sampling glochidia from fish gills was evaluated. Together, these studies address key knowledge gaps in salmon movement ecology and brook floater host associations, supporting improved conservation and management strategies.