Proceedings of the Third World Fisheries Congress: Feeding the World with Fish in the Next Millenium—The Balance between Production and Environment
Effect of Nutritional Deprivation and Delayed Feeding on Growth, Survival, Proximate Composition, and Condition Indices of Freshwater Crayfish Marron Cherax tenuimanus (Smith)
Commercial aquaculture of crayfish in Australia began in the 1970s (O’Sullivan 1995) and currently is based on the culture of three species: marron Cher-ax tenuimanus (Smith 1912) in Western and South Australia (Evans and Fotedar presented paper; Fotedar et al. 1996a, 1996b), yabby C. destructor (Clark 1936) in Western Australia and eastern states (Mills and McCloud 1983), and redclaw C. quadricarinatus (von Martens 1868) in Queensland and Northern Territory (Curtis and Jones 1995; Jones 1990). Freshwater crayfish are usually cultured in earthen ponds (Geddes et al. 1988; Jones 1990, 1995; Morrissy 1979, 1992a, 1992b). However, there is some interest in rearing marron under superintensive culture systems. This system may be called battery culture, intensive crayfish culture system (ICCS), or “Nardi” system. In these systems, marron are housed in individual compartments in indoor tanks. The higher density of marron (i.e., a large volume of crayfish to a small volume of water) than in ponds permits a higher degree of control. This system is highly capital intensive and has not been proven commercially viable but remains subject of a research (Morrissy 1992b).
Freshwater crayfish, like many other crustaceans, are subjected to food scarcity and prolonged starvation in their natural environment (Gu et al. 1996). Furthermore, in ICCSs, the lack of natural productivity often results in deprivation of certain nutrients available for the cultured crayfish. Consequently, they undergo some alterations in their normal physiological and biochemical processes, and their nutritional status is altered during these nonfeeding periods (Hochachka and Somero 1984).
Depleted protein, carbohydrate, glycogen, and lipid reserves and reduced metabolic rates have been associated with nutritional deprivation in crayfish and other crustaceans (Edsman et al. 1993; Hazlett et al. 1975; Marsden et al. 1973; Regnault 1981; Speck and Urich 1969). Marsden et al. (1973), Hazlett et al. (1975), Cuzon et al. (1980), and Regnault (1981) have examined the qualitative and quantitative changes in the body composition of crustaceans in response to starvation. Many species reduce their metabolic rates and start depleting protein, carbohydrate (glycogen), and lipid reserves during nutritional deprivation (Hazlett et al. 1975; Marsden et al. 1973). The relative importance of these reserves and their order of utilization depends on species, recent feeding history, and length of starvation (Schirf et al. 1987). In some species, carbohydrates are used initially, then lipids, and finally proteins (Chaisemartin 1971; Cuzon and Ceccaldi 1972). In others, carbohydrate use is negligible; the reserves used are predominantly lipids (Schafer 1968) or proteins (Marsden et al. 1973; Neiland and Scheer 1953). Barclay et al. (1983) reported that protein is the major source of energy during 14 d of starvation in tiger prawn Penaeus esculentus. Schirf et al. (1987) studied the qualitative and quantitative changes in proximate composition of the tail muscle and hepatopancreas in red swamp crayfish Procambarus clarkii. Hepatosomatic index and carbohydrate levels in tail muscle have been used previously as indicators of nutritional deprivation in marron crayfish (Evans et al. 1992).
After certain periods of starvation, juvenile redclaw crayfish require time to return to the normal nutritional or physiological state (Gu et al. 1996). Edsman et al. (1993) report that protein synthesis in juvenile signal crayfish Pacifastacus leniusculus increases after the first day of feeding after starvation and returns to normal concentrations after 4 days of feeding.