Loading...
4 results
Search Results
Now showing 1 - 4 of 4
- 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 effects of rearing temperature on reproductive conditioning of stalked barnacles (Pollicipes pollicipes)Publication . Franco, Sofia C.; Aldred, Nick; Sykes, António V.; Cruz, Teresa; Clare, Anthony S.Pollicipes pollicipes (Crustacea; Pedunculata) is a delicacy on the Iberian Peninsula where, in recent years, stock shortages associated with high market value have increased interest in the aquaculture potencial of this species. Though broodstock has been maintained in captivity, detailed culture conditions are lacking.
- Effects of using live grass shrimp (Palaemonetes varians) as the only source of food for the culture of cuttlefish, Sepia officinalis (Linnaeus, 1758)Publication . Sykes, António V.; Domingues, Pedro M.; Andrade, José PedroThe life cycle of cuttlefish fed ad libitum exclusively on live grass shrimp (Palaemonetes varians) was studied during 5 consecutive generations. Different culture temperatures promoted different (P < 0.05) exponential growth for each life cycle, being summer generations shorter than those of winter. Higher temperatures promoted higher IGR’s and mortality, while lower temperatures promoted increased life span, reproduction stages, total fecundity and total egg biomass. Increased generations also seemed to increase fertility. A ‘‘hybrid’’ generation promoted the best results in terms of hatchling weight, individual fecundity and fertility. Mean egg weight was related to female size and embryonic development took longer at lower temperatures. Brood stock sex ratios seemed to be temperature related.All of these culture aspects were also compared between themselves in order to establish future brood stock methodologies. Grass shrimp proved to be a good diet for the culture of cuttlefish throughout the life cycle. The use of only one species reduces costs and labor associated to cuttlefish culture.
- The effects of temperature in the life cycle of two consecutive generations of the cuttlefish sepia officinalis (Linnaeus, 1758), cultured in the Algarve (south Portugal)Publication . Domingues, Pedro M.; Sykes, António V.; Andrade, José PedroWe are presently culturing the 4th generation of the cuttlefish, Sepia offıcinalis in our laboratory. A first generation (F1) was grown from eggs collected from the wild (Ria Formosa – South Portugal) during the summer, at mean temperatures of 27 °C ± 3°. In the present study, a second generation (F2), originated from eggs laid in the laboratory by females from F1 was cultured between the start of autumn and the end of spring, at mean temperatures of 15 °C ± 4 °C. The life cycle of cuttlefish from F2 was compared to F1. Populations of 30 cuttlefish were used in each experiment. Cuttlefish were grown from one day old until the cycle was completed (when the last female in each population had died). Cuttlefish from F2 cultured at much lower temperatures had a longer life cycle, of almost 9 months (260 days) compared to cuttlefish from F1, which completed their cycle in less than 6 months (165 days). Cuttlefish from F2 grew significantly larger (U = 0.00; p < 0.01) with mean weights of 343.3 ± 80.5 g and 248 ± 33.1 g for males and females, respectively, compared to F1 (199.6 ± 40 g and 143.3 ± 30.9 g for males and females, respectively). Females from F2 had higher fecundity (225 eggs female− 1) compared to females from F1 (144 eggs per female−1), produced bigger eggs (t = 45.60752; p < 0.0001), weighing 0.74 ± 0.18 g, compared to 0.46 ± 0.11 from F1, and bigger hatchlings (t = 7,144783; p < 0.0001), weighing 0.10 ± 0.02 g, compared to 0.09 ± 0.02 g for the summer population.