EFFECTS OF TEMPERATURE ON GASTRIC EVACUATION RATES IN SEPIA OFFICINALIS (LINNAEUS, 1758) IN LABORATORY CONDITIONS

摘要

In this study, the gastric evacuation rates of cuttlefish (Sepia officinalis), fed a single meal of shrimp, Paleomonetes varians, were measured in the laboratory at four temperatures (15.5, 18, 21 and 23℃). Linear, square root, and exponential models were fitted to the percentage of the original meal remaining (ash free dry weight). The square-root model gave the best fit for experiments performed at 15.5℃ and 18℃, whereas the exponential model gave the best fit for experiments carried out at 23℃. The square-root model showed an increase in the amount of food remaining after the fifth hour in all four experiments. There was a significant difference in gastric evacuation rates between the temperatures tested. Gastric evacuation rates were higher at higher temperatures (0.442 h~(-1) at 23℃) in comparison with lower temperatures (0.198 h~(-1) at 15.5℃, 0.212 h~(-1) at 18℃, and 0.323 h~(-1) at 21℃). Significant differences in gastric evacuation rates between size and maturation stage have been calculated for experiments performed at 23℃.