MEPS 517:85-104 (2014)  -  DOI: https://doi.org/10.3354/meps11024

ABSTRACT: Temperature is considered one of the major factors shaping marine zooplankton distribution, abundance and phenology. During the past decades, the Barents Sea experienced strong temperature fluctuations, but previous studies have not identified a clear link between temperature and the dynamics of the key copepod species Calanus finmarchicus. We investigated associations between regional and local water temperature and C. finmarchicus abundance in Atlantic waters of the Norwegian and Barents Seas between 1959 and 1992. Results differed depending on the developmental stage, season and area, emphasising the value of detailed data series in climate effect studies. Abundances of copepodite stage CV and adult females showed no strong correlations with regional temperature indices, but were positively linked to local temperature in both spring and summer. For nauplii and young copepodite stages (CI-CIV), associations with both regional and local temperature estimates were positive in spring, but negative in summer. The results indicate that the phenology of young copepodites may be particularly responsive to climate change, which in turn may influence predators feeding on these life stages.

KEY WORDS: Barents Sea · Copepod · Climate change · Generalised additive models · Norwegian Sea · Seasonality · Temperature · Zooplankton