Feeding rates, growth rates and feed efficiency ratios were studied in experimentally reared Sepia officinalis hatched from eggs collected from three locations (Menai Bridge, Plymouth and Southampton). Groups of newly hatched cuttlefish were either maintained at 19°C and well fed or were held at ambient seawater temperature (7-16°C) with little food for 6 months so that their development was delayed and then transferred to optimum conditions. No significant differences in growth rates, feeding rates and feed efficiency ratios were observed between cuttlefish from the 3 locations. Cuttlefish whose development was initially delayed after hatching and then were stimulated to
grow under optimum conditions, (19°C and fed), showed similar growth rates to those held under optimum conditions of seawater temperature (19°C) and food supply shortly after hatching. Different sized cuttlefish hatched at different times from batches of eggs laid by one female were maintained under similar conditions. Early hatched cuttlefish maintained a size advantage over late hatched individuals. The effect of density (175- 877 cuttlefish.m-² ) on juvenile growth, feeding rates, feed efficiency ratios, final biomass and the effect of crowding on mortality and cuttlefish behaviour were determined. No significant differences in growth rates, feeding rates and feed efficiency ratios were observed. However at higher densities (>526 cuttlefish.m-² ) lower survival and a higher incidence of damaged mantle edges were observed.
The effects of hypoxia, starvation, body size (0.04-18.5 g), activity and temperature (10- 25ºC) on the oxygen consumption of S. officinalis were determined. Acclimated cuttlefish at 8, 13, 15, 18 and 23°C, exposed to acute temperature changes (6-28°C), were highly temperature dependent up to a certain point, which was different for each acclimation group, beyond which thermal dependence on aerobic metabolism completely diminished. Circadian rhythmicity in respiration was apparent, following a 5 and 10°C temperature shift, and complete acclimation was achieved after 6.2 and 7.4 days respectively. The effect of 'apparent SDA' and its components, particularly the energetic cost associated with mechanical movement of the food, in cuttlefish fed a variety of single meals (0.83 -18.82%BDW.d-¹ ) at 15 and 20 °C was determined and the impact of a single meal on the total energy budget investigated.