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- Effects of culture density on growth and broodstock management of the cuttlefish, Sepia officinalis (Linnaeus, 1758)Publication . Correia, Miguel; Domingues, Pedro M.; Sykes, António V.; Andrade, José PedroThe effects of culture density on growth and broodstock management of the cuttlefish S. officinalis were studied. Cuttlefish used were one month old at the start of the experiment, on average; two densities were used (16 and 76 cuttlefish m 2). During the first experiment (until day 43), dead cuttlefish were replaced by individuals of similar weight. From that day onwards, no cuttlefish were replaced. No significant differences in growth and feeding rates, or food conversions were found between densities, during the first experiment. Results indicate that densities up to 76 cuttlefish m 2 are suitable for cuttlefish weighing approximately 10 g. After day 43 until first female layed eggs (second experiment), no statistical differences were found between densities for all the parameters studied with the exception of growth. In this case, cuttlefish cultured at the lower density grew more than those ones cultured at the higher density, with average weights at the start of egg laying of 137.3F21.6 and 91.8F12.3 g, respectively. This difference in growth could be explained mainly by the different culture densities and biomass associated. Fecundity obtained for cuttlefish cultured at the lower density (834 eggs female 1) was higher than for those ones cultured at the higher density (290 eggs female 1), however fertility was higher for the higher density. These results were expected, since fecundity is directly related to the size of females. Significant differences were found in fertility (hatching percentage) between densities. Mean hatching percentage was of 35.8F9.4% and 62.0F16.9% for low and high density, respectively. This difference was unexpected since we expected eggs from females cultured at lower densities to have higher quality. Mean hatchling weight was of 0.079F0.011 and 0.072F0.012 g for low and high density respectively, and significantly different. Results indicate that lower culture density promoted higher growth, larger eggs and hatchlings, but had no influence on juvenile and adult survival. On the contrary, eggs from females cultured at higher densities resulted in higher hatching rates.
- Growth of young cuttlefish, sépia offcinalis (Linnaeus 1758) at the upper end of the biological distribution temperature rangePublication . Domingues, P. M.; Kingston, T.; Sykes, António V.; Andrade, José PedroIndividual growth rates, feeding rates (%BWd-1) and food conversions for cuttlefish (S. officinalis) hatchlings and juveniles were determined during this study. A flow-through system was used. Water temperature reached 30 °C during the hottest part of the day, gradually decreasing to 25 °C during the night; salinity varied between 37 6 3 ppt and lights were kept on for 14 h day-1. Hatchlings were placed in separate compartments with a water volume of 1.2 L. Juvenile cuttlefish (from 0.5 to 25 g) were placed in bigger baskets, with a water volume of 5.2 L. Water flow was 120 L h-1. The biggest cuttlefish used in these experiments (> 25 g) were gathered in groups of five and placed in circular tanks (water volume of 250-300 L).
- The influence of culture density and enriched environments on the first stage culture of young cuttlefish, Sepia officinalis (Linnaeus, 1758)Publication . Sykes, António V.; Domingues, Pedro M.; Loyd, Maria; Sommerfield, Anne; Andrade, José PedroThe cuttlefish (Sepia officinalis) is one of the most well-known cephalopods (Boletzky 1983). Successful culture throughout the life cycle has been done in many places around the world (Pascual 1978; Forsythe et al. 1994). However, it is known that the first stage culture of this species is the most problematic phase and when most mortality occurs (Richard 1971; 1975; Domingues et al. 2001). Recent studies showed that grass shrimp (Palaemonetes varians) can and should be considered as an adequate prey for the culture of the early stages of cuttlefish. It promotes very similar results in life span, survival, and growth, when compared to mysids (Sykes, unpublished results). Furthermore, grass shrimp has been used successfully to culture cuttlefish throughout the life cycle (Domingues et al. 2002, 2003). One of the most important aspects in commercial culture of marine animals is culture density. These studies are important to maximize biomass cultured in each tank while attaining optimal growth and survival, to reduce production costs.