Article

Patterns of declining zooplankton energy in the northeast Atlantic as an indicator for marine survival of Atlantic salmon

Details

Citation

Tyldesley E, Banas NS, Diack G, Kennedy R, Gillson J, Johns DG & Bull C (2024) Patterns of declining zooplankton energy in the northeast Atlantic as an indicator for marine survival of Atlantic salmon. Juanes F (Editor) ICES Journal of Marine Science, 81 (6). https://doi.org/10.1093/icesjms/fsae077

Abstract
Return rates of Atlantic salmon (Salmo salar) from the sea to European rivers have declined in recent decades. The first months at sea are critical for growth and survival; recent evidence suggests that reduced food availability may be a contributory factor to the observed declines. Here, zooplankton abundance data are used to derive a measure of prey energy available to forage fish prey of salmon during early marine migration. This zooplankton prey energy has significantly and dramatically declined over much of the northeast Atlantic, and specifically within key salmon migration domains, over the past 60 years. Marine return rates from a set of southern European populations are found to exhibit clustering not entirely predictable from geographical proximity. Variability in grouped return rates from these populations is correlated with zooplankton energy on a range of scales, demonstrating the potential use of zooplankton energy as an indicator of salmon marine survival. Comparison with environmental variables derived from ocean model reanalysis data suggests zooplankton energy is regulated by a combination of climate change impacts on ecosystem productivity and multi-decadal variability in water mass influence along the migration routes.

Keywords
Salmo salar; marine survival; ecosystem-based management; forage fish larvae; zooplankton; Calanus; copepods; oceanography; North Atlantic Ocean; continuous Plankton Recorder

Journal
ICES Journal of Marine Science: Volume 81, Issue 6

StatusPublished
FundersAST Atlantic Salmon Trust
Publication date31/08/2024
Publication date online22/06/2024
Date accepted by journal20/05/2024
URLhttp://hdl.handle.net/1893/36266
PublisherOxford University Press (OUP)
ISSN1054-3139
eISSN1095-9289

People (1)

Dr Colin Bull

Dr Colin Bull

Senior Lecturer in Aquaculture, Institute of Aquaculture

Projects (1)

Secondment to Atlantic Salmon Trust
PI:

Files (1)