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- 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).
- Nucleic acid derived indices or instantaneos growth rate as tools to determine different nutritional condition in cuttlefish (Sepia Officinalis, Linnaeus 1758) HatchingsPublication . Sykes, António V.; Domingues, Pedro M.; Andrade, José PedroWhen culturing any species in intensive aquaculture, time of first feeding is of extreme importance. Food should be available when larvae or hatchlings are finishing the absorption of the inner yolk reserves and starting to feed externally. Cuttlefish are known to be voracious feeders throughout their life cycle and accept a wide range of prey (Guerra 1985, Castro & Guerra 1989, Pinczon du Sel & Daguzan 1992, Domingues et al. 2001a, Domingues et al. 2003). Some authors (Wells 1958, Richard 1971, Richard 1975, Boletzky, 1983, Boletzky 1987, and Nixon 1985) have studied the embryonic development and the early life history of cuttlefish and set the end of the inner yolk reserves around the 3rd day of life.However, according to Domingues et al. (2001b), cuttlefish in unfed or poor nutritional condition (as result of prey with poor nutritional profile) can last as much as 20 days. The only way to determine optimal timetables for first feeding, thus optimizing cuttlefish production, is the use of condition analysis. Condition is a measure of the physical status or well being of an animal and may be used to evaluate growth or survival rates (Bolger & Connoly 1989, Ferron & Leggett 1994).
- The effects of light intensity on growth and survival of cuttlefish (sepia officinalis) hatchlings and juvenilesPublication . Sykes, António V.; Quintana, Daniel; Andrade, José PedroCephalopods, particularly the European cuttlefish (Sepia officinalis), are considered to be potential species for aquaculture diversification due to their high growth rates in captivity (Domingues, Sykes & Andrade 2001; Domingues, Bettencourt & Guerra 2006) and great demand as food throughout different regions of the world (FAO 2009). Nonetheless, cuttlefish differ from fish in several biological aspects, thus requiring different approaches to solve similar or new problems associated with their culture. For instance, the hatchling stage has been identified as the most problematic due to mortality and the need of live prey. Several factors might influence growth and mortality of cuttlefish in captivity, such as culture conditions and nutritional requirements of the species. According to Downing and Litvak (1999), there is a need to understand the physical and biological factors that act on developing fish larvae to create protocols that maximize survival and growth under culture conditions. It is known that system design may promote stress and lower animal welfare in finfish (Conte 2004) and the same seems to apply to cuttlefish.
- Characterization of deformed hatchlings of Octopus vulgaris obtained under captivity from a small femalePublication . Jiménez-Prada, Pablo; Scherbakova, Anastasia; Riera, Rodrigo; Felipe, Beatriz C.; Sykes, António V.; Gonçalves, Rui A.; Andrade, José Pedro; Perales-Raya, Catalina; Rodríguez, Covadonga; Almansa, EduardoThe common octopus (Octopus vulgaris), a promising species for aquaculture, spawns easily under cap-tivity from mature females (usually above 1 kg wet weight). Octopus juveniles and adults are collectedfrom nature to obtain eggs and paralarvae for aquaculture development trials. In July 2011, a very smallfemale (150 g wet weight but with an age estimation of 300 days-old) spawned almost 77,000 paralar-vae. Malformations of paralarvae were noticed in the first spawning days, namely the absence of arms.Despite not being lethal, these abnormalities might be derived from the physiological condition of thebreeding specimen (the female’s lower weight to the estimated amount of living days), which might beeventually related to nutritional unbalances or genetic parameters that were transferred to the eggs.
- Nucleic acid derived indices or instantaneous growth rate as tools to determine different nutricional condition in cuttlefish (Sepia officinalis, linnaeus 1758) hatchlingsPublication . Sykes, António V.; Domingues, Pedro M.; Andrade, José PedroTwo groups of 100 cuttlefish hatchlings each were used to determine the duration of the yolk reserves, during which growth can be obtained with no food supply. One group was fed live grass shrimp ad libitum from the 3rd day of life onwards, while the other was starved during the whole experiment. The experiment lasted 7 days, because this was the 1st day where a negative growth rate was obtained. Nucleic acid derived indices and instantaneous growth rates (IGR) were used as a way to describe their condition, when all the yolk reserves would be exhausted and to determine the most accurate tool to express growth and condition. RNA/DNA ratios described clearly the differences (P < 0.05) between fed and starved hatchlings cultured at 23 ± 2°C, especially from day 4 onwards. Correlation between IGR and RNA/DNA ratios was only attained for the starved population (R 0.90; P 0.0374). DNA concentration was identical (P > 0.05) between groups and did not displayed a clear pattern with increasing age. Correlation between IGR and DNA was only attained for the fed population (R −0.90; P 0.0374). RNA concentration values were different from day 5 onwards. Any of the nucleic acid derived indexes were not accurate enough to express growth and condition, so IGR seems to be the most accurate and inexpensive way to describe hatchlings growth and condition in controlled conditions.