Faecal pellet production (FPP) and respiration rates of
Calanus glacialis,
C. hyperboreus and
Metridia longa were measured under land-fast ice in the southeastern Beaufort Sea during the winter–spring transition (March–May 2004) prior
to the phytoplankton spring bloom. Despite different overwintering and life cycle strategies and remaining low concentrations
of suspended chlorophyll
a and particulate organic matter, all species showed increasing FPP rates in spring. A corresponding increase in respiration
was only observed in
C. glacialis, while respiration remained constant in
C. hyperboreus and
M. longa. In
C. glacialis and
C. hyperboreus calculated ingestion covered respiratory expenditures. The constancy of the oil sac volume in
M. longa suggests that the animals fed during winter-spring. Pre-bloom grazing as shown here seems to acclimate the copepod populations
physiologically for the upcoming high feeding season, so that they are able to resume maximum grazing and reproduction as
soon as the phytoplankton bloom is initiated.