Semi-extensive nurseries in lagoons/ponds (Greece, France, Italy, Portugal)

In order to improve performance of fish juveniles in extensive and semi-intensive on-growing systems, using juveniles of high quality and performances is of primary importance. In contrast to intensive farmed fish, the capacities to escape predators (e.g., birds), feed on natural preys, and stand up fluctuations in water quality, are essential. In fact, one of the limitations of extensive and semi-intensive on-growing systems has been supply of farmed fry of quality.

Traditionally, wild fry has been the source of quality juveniles for extensive systems. Although capture of wild fry is illegal in many countries, improved farmed fry quality would certainly lower the pressure for subsisting practices of traditional capture of wild fry for such systems. Some advances in this direction have been obtained by using semintensive techniques. Fish fry produced in mesocosms systems (including large volume systems) are very close to the wild phenotype when compared with intensively produced juveniles.

Fingerlings produced in mesocosms systems may not only exhibit morphological differences from intensively produced ones, but may show as well a higher growth potential and an increased viability. Juveniles transferred to extensive systems may encounter adverse conditions in terms of predation pressure and wider range of environmental conditions, when compared to rearing under controlled conditions in intensive systems.

Publications

D39 Semi-extensive nurseries in lagoons/ponds

D42 Scientific publication on enhancement of productivity of earthponds in semi-intensive by Aquamats

D44 Scientific/Technical publication on periphyton-based system as pond management for juvenile fish production

D68 Scientific/Technical publication on Semi-extensive fish nurseries in lagoons/ponds