EGG-PRODUCTION RATES OF CALANUS-FINMARCHICUS IN THE NORTHWEST ATLANTIC (LABRADOR SEA)

Egg production rates and population characteristics of Calanus finmarc hicus were examined in the Labrador Sea during the spring of 1994. Sev eral experiments were conducted in order to compare egg production rat es and clutch size using different types of container and in the prese nce and absence of food. In one series of experiments, individual fema les were incubated either in petri dishes or in polycarbonate bottles (80 mL) in filtered seawater. In these experiments, clutch sizes and e gg production rates were not significantly different. In a second seri es of experiments, groups of 20 females were placed in containers unde r three sets of conditions: in the presence of food and with a screen to separate copepods from their eggs (FSCREEN), in the presence of foo d without a screen (FOOD), and in filtered seawater without a screen ( FSW). Average egg production rates of female C. finmarchicus were sign ificantly higher in the FSCREEN treatments than in either of the other two. In these experiments, egg production rates were not obviously re lated to ingestion rates, and these in vitro observations together wit h observations of in situ conditions suggest that stored reserves may have been used to fuel, or supplement, reproduction in C. finmarchicus in this area.