Surface trawl survey for U.S. origin Atlantic salmon
Abstract:A surface trawl survey (2001–2005) in Penobscot Bay, Maine, U.S.A., and the nearshore Gulf of Maine waters was conducted to investigate early marine dynamics of a hatchery‐dependent Atlantic salmon Salmo salar population from a severely modified river system. Data generated were used to evaluate the effect of stocking location and time on migration success and to describe the migratory pathways and environments that post‐smolts traverse. Significant differences in early migration success were detected among different stocking groups, but subsequent marine survival was independent of stocking group. While the post‐smolt population was primarily composed of hatchery origin smolt‐stocked fish, other life‐stage stocking strategies (i.e. parr stocking) represented a higher proportion of the population than previously assumed. Catch distribution suggests evidence of an initial marine migratory pathway out of the dynamic Penobscot Bay environment. The hypothesized benefits of a predator refuge based on the co‐occurring species complex is considered minimal for emigrating post‐smolts given a mismatch in the size overlap among species and low abundance of other co‐occurring diadromous populations. These data can be used to modify current management actions to optimize S. salar recovery and inform future research agendas.
Document Type: Regular Paper
Publication date: August 1, 2011