Rearing endangered atlantic salmon (Salmo salar) in modified marine aquaculture systems for population conservation in Eastern Canada

Abstract

We document the first known marine aquaculture farm established and dedicated to rearing wild-origin Atlantic salmon (Salmo salar) for population restoration. Juvenile salmon of a common lineage were collected from the wild in Fundy National Park, in Eastern Canada and reared in a captive marine environment using modified commercial aquaculture systems. Each year from 2015 to 2024, cohorts of mature fish were tagged at the marine farm and transferred by truck for release back into to the Upper Salmon River in Fundy National Park, at the time they would be naturally returning from sea to spawn the next generation. Our rearing and release strategy avoided high mortality during the marine life stage, which is the factor most limiting population recovery. Post-released adult salmon were observed returning naturally in subsequent years from 2016 to 2024. This work contributed to our objective to increase counts of returning adult salmon, which were otherwise absent from 1995 to 2007, following a population collapse. The scale of benefits from released and returning salmon require further quantification, but the current study provides a promising template for consideration and implementation by other jurisdictions that are facing futures without salmon, and the associated loss of benefits to ecosystems, community, and culture that follow.