Local variations in size and activity among Calanus finmarchicus and Metridia longa (Copepoda, Calanoida) overwintering on the west coast of Norway. Journal of Plankton Research, 01 January 1994 to 31 December 2002 (NODC Accession 0000489)

Vertical net hauls were taken at thirteen stations between latitude 60 degrees 8 minutes N - 61 degrees 20 minutes N and longitude 3 degrees 4 minutes E - 7 degrees 0 minutes E in late November 1980. Size and activity characteristics of Calanus finmarchicus and Metridia longa were studied. Significant differences were noted between C. finmarchicus from different stations. Average body length, dry weight, protein and lipid contents, gonad development, and amylase and trypsin activities varied but average gut fullness and trypsin/amylase ratio appeared constant. M. longa from different stations showed significant differences in average body length, dry weight, protein content, amylase / trypsin activities and gut fullness, but there were no apparent variations in lipid content and trypsin/amylase ratio. Those animals inhabiting the most seaward station tended to show the most specific local characteristics. M. longa had consistently lower lipid proportion with higher gut fullness and digestive-enzyme activities than C. finmarchicus. The results therefore indicate that C. finmarchicus had assumed a winter state of low activity with dependence on stored energy, while M. longa relied more upon utilization of available food.