ENERGY-CONSUMPTION OF THE CUTTLEFISH SEPIA-OFFICINALIS L (MOLLUSCA, CEPHALOPODA) DURING EMBRYONIC-DEVELOPMENT, PRELIMINARY-RESULTS

A cluster of eggs of the cuttlefish Sepia officinalis L. laid by a female measuring 23 cm (DML), were developed under experimental conditions, with controlled water temperatures ranging from 15, 18, 21 and 24-degrees-C. The energy discharge of eggs and hatchlings was also measured by using the direct calorimetry method, with a Parr bomb calorimeter. A logarithmic relation shows that all eggs over 75 mg dry weight, contain an equal quantity of energy 1600J. The energetic budget summarizing the utilization of yolk during the embryonic development, enabled the author to explain significant differences between the size of hatchlings in relation to the incubation temperature. Thus at 15-degrees-C 41% of the egg-yolk is used during growth-rate, and only 10% for catabolitic processes; respiration or excretion. On the contrary at the temperature of 24-degrees-C yolk utilization is in deficit for growth-rate (15%), and in excess for catabolism (52%). Energetic values of yolk and hatchlings is about 18 J.mg-1. The experimental method on the eggs of one female is discussed by emphasizing the initial quantity of yolk relative to the size of the female.