Hygum BH, Rey C, Hansen BW, Carlotti F
carbon, Calanus, cohort, development, lipid, mesocosm, Espegrend, Bergen, Norway, 18.5 m3
Cohort development and nutritional conditions of Calanus finmarchicus were studiedin experimental seawater mesocosms in a Norwegian fjord. Artificially added cohortsdeveloped from early naupliar stages to copepodite stage IV in 41–43 days at ambienttemperature increasing from 4.3 to 6.8 C. A natural stock of C. finmarchicus, initiallydominated by early copepodite stages, developed to CV, males and females. Totalstorage lipid increased exponentially until CV. Individual body carbon weightincreased sigmoidally with age. Relationship of body carbon weight (W, g) toprosome length (L, m) determined for copepodites and adults (W=2.6 10 10 L3.45,r2=0.92) showed a higher weight than from in situ studies. This investigationdemonstrates (i) that cohorts of C. finmarchicus can be reared successfully inmesocosms, (ii) a good nutritional state of copepods in terms of body carbon contentand lipid reserves, and (iii) that part of the final CV moulted to both males andfemales.