Effects of increased tank bottom areas on cuttlefish (Sepia officinalis,L.) reproduction performance

The objective of this research was to determine the effects of using tanks with different bottom areas/volumes on the growth and reproduction of the European cuttlefish, Sepia officinalis. One hundred and eighty‐four juvenile cuttlefish (46.1 ± 20.9 g) were used to test replicates of 9000 L (6.67 m²), 750 L (1.54 m²) and 250 L (0.79 m² – control). Growth and reproduction data were registered. In addition, egg proximate composition differences were assessed by collecting egg samples from each tank. Regarding growth, no statistical differences between tank types were found (P > 0.05), but total absolute mortality was lower in 9000 L tanks. As for reproduction, differences were found (P < 0.05) between individual tanks for mean egg (MEW), male (MW ♂ ) and hatchling (MHW) weights; and egg batch number. One of the 9000 L tanks displayed the highest overall and individual fecundity (16 593 and 1383 eggs respectively) and egg viability (~72%) ever obtained in our facilities. Differences (P < 0.05) regarding egg proximate composition of different tanks were noted. Significant (P < 0.05) correlations were established between the duration of reproduction stage and batch, MEW and MW♀, egg viability and MHW, and MHW and egg ash content. The present results might be related to sex ratios, differences in weight between ♀ and ♂, and/or derived from breeders condition.