North Pacific Anadromous Fish Commission

Technical Report 15

Table of Contents

Supplementation of Atlantic Salmon in the Southern Extent of their Range: Evaluation of Age-1 Hatchery Smolt Stocking in a Small Coastal Watershed

Authors:
James P. Hawkes, Graham S. Goullete, Alejandro M. Moctezuma, Ernie J. Atkinson, and Oliver N. Cox

Abstract Excerpt:
Atlantic salmon (Salmo salar) populations at the southern extent of their range have experienced precipitous declines over several decades and abundance is critically low. This species requires conservation hatchery supplementation in order prevent extirpation while other interventions (e.g., habitat improvements) proceed with the goal of population recovery when conditions improve. The Narraguagus River, a small coastal Maine Atlantic salmon river, has experienced low (10–40) but persistent spawners originating from natural production of approximately 1,200 smolts annually (USASAC 2019). In an effort to enhance adult returns, an annual stocking of 40,000 age-1 hatchery reared smolts took place from 2008–2012. This effort had limited success, with 154 two sea-winter adult returns (5.6 two sea-winter adults/10,000 smolts). These rates are much lower than extrapolated numbers of 63.2 two sea-winter adults per 10,000 smolts for their wild counterpart. Hatchery inputs have been described as inferior (McCormick et al. 1998), but it is unclear why a ten-fold difference exists between these groups. In 2016, smolt stocking was reinitiated, with plans for nearly 100,000 smolts stocked annually over a four-year period. In collaboration with hatchery managers and regional biologists, we initiated a two-year telemetry study with hopes of pinpointing constraints in stocking effectiveness as well as describing the migration dynamics of these tagged fish.

*This is the first paragraph of an extended abstract. Download the full abstract below.

DOI:
https://doi.org/10.23849/npafctr15/197.199.

Citation

Hawkes, J.P., G.S. Goullete, A.M. Moctezuma, E.J. Atkinson, and O.N. Cox.  2019.  Supplementation of Atlantic salmon in the southern extent of their range: evaluation of age-1 hatchery smolt stocking in a small coastal watershed.  N. Pac. Anadr. Fish Comm. Tech. Rep. 15: 197–199.  https://doi.org/10.23849/npafctr15/197.199.