52 DECEMBER 2013 • WORLD AQUACULTURE • WWW.WAS.ORG (Sykes et al. 2003). Figure 3 shows a common seawater system setup with 10-L raceway tanks in a flowthrough system, which may hold 500 cuttlefish hatchlings through this stage, depending on temperature. We tried to enhance cuttlefish growth and survival by using enriched frozen food from the first day after hatching, similar to Koueta et al. (2002). The results were worse than using non-enriched frozen grass shrimp, perhaps a result of underdevelopment of the digestive system, as verified through histology. The nutritional value of different food items and the assessment of metabolic needs of cuttlefish were also addressed in research on this life-stage. Juvenile stage At this stage, cuttlefish may be reared at maximum densities of 120 juveniles/ m2 (Domingues et al. 2003a, Correia et al. 2005) but dissolved oxygen, feed supply (10-15 percent body weight/d) and bottom area requirements are high (Figs. 4A and 4B). Typical feed conversions are 35-50 percent (Sykes et al. in press). We are currently testing different raw materials for prepared diets (Fig. 4C). The lack of inappropriate food will promote cannibalism on smaller or feeble individuals. Cuttlefish growth is normal (6 percent body weight/d) and no mortality occurs when fed frozen grass shrimp (Domingues et al. 2003b, Domingues et al. 2004). Juveniles are solitary in nature but, in captivity, individuals congregate and school like fish (Figure 4D). Current research includes determination of the daily food supply, energy and metabolic requirements. Because of new EU legislation on animal welfare (which now includes cephalopods), we have assessed the current knowledge applicable to the law (Sykes et al. 2012a) and tested different anaesthetics for handling (Gonçalves et al. 2012). Adult stage Adult cuttlefish display typical behavior and a zebra-stripe pattern (Fig. 5) that is more intense in males. The establishment of a broodstock protocol based on biological constraints has been attained through the culture of six successive generations (Correia et al. 2005, Sykes et al. 2006a). Reproductive performance may be improved with the use of tanks with larger bottom areas (Sykes et al. 2009, Sykes et al. 2012c). In the first years of cuttlefish culture at CCMar, mature females stopped feeding and spawned only once. Under improved conditions, the number of eggs per female obtained and the frequency of intermittent spawning has increased. Currently females spawn more than once during the only breeding season of a given cuttlefish stock and cuttlefish feed between spawns. We identified variables that might influence cuttlefish reproduction in captivity. We are currently determining the best type of tank to increase reproductive output, based on possible changes in behavior that will lead to different parental contributions. The latter is particularly important because the collapse after seven successive generations (Forsythe et al. 1994) may be the result of inbreeding. Typically two generations are produced each year: a summer generation with a 3-4 month life cycle and a winter generation with a 7-9 month life cycle (Sykes et al. 2006a). Only grass shrimp is currently used to achieve generational culture. The acceptance of frozen food from the first day after hatch suggests that cuttlefish may accept a prepared diet from that time. Zootechnological studies have optimized tank color and light intensity. An overview of cuttlefish culture may be found on the Internet (www.ccmar.ualg.pt/fbh/sepiameta/sepiametapublications. html). Future Objectives • Improve the reproduction protocol and maximize control over egg quantity and quality through the use of different sex ratios and paternity gamete contribution; • Improve knowledge of nutritional requirements and the development of prepared diets; • Develop different products for human consumption based on cuttlefish mantle meat — cuttlefish fillet and surimi; • Develop novel products based on cuttlefish viscera, ink and cuttlebone. Collaborators We have extended our network of collaborations beyond CCMar, which now includes the following researchers: Eduardo Almansa and Pedro Domingues (Spanish Institute of FIGURE 5. Pair of adult cuttlefish, (male (♂) on the left and female (♀) on the right. (Photo: A. Sykes).
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