the effects on tissue composition were less definitive. Sepioteuthis
juveniles on the highest rations had higher concentrations of water, but no difference in lipid,
carbohydrate or protein when compared with their lower ration siblings. In the case of juvenile
cuttlefish no difference in tissue composition was detected between the two ration levels.
RNA:protein ratios were also determined for the juveniles to provide an estimate of instantaneous
growth. A significant correlation was found between body size and RNA:protein ratio in the squid;
those juveniles that ate more had higher RNA:protein ratios than lower ration individuals.
Significantly, the juvenile cuttlefish showed no relationship between growth rate and RNA:protein
ratios, which means that we are unable to use this measure to estimate the growth rates of wild
individuals. In conclusion, ration level did affect growth rates and food availability is an important
factor in modifying growth rates of wild individuals. However, we could not find, at the individual
level, an index or measure that could be used to explain the variability of observed differences in
growth rates as a function of nutritional history. Ó 2000 Elsevier Science B.V. All rights
reserved.