《鱼类养殖学》01.ppt

Chapter 1 Introduction第一章 绪论 1.1 FISH CULTURE PRODUCTION IN PRACTICE AND THEORY OF FISH CULTURE Fisheries, including freshwater fisheries and marine fisheries according to production waters, are referred as a commercial production and husbandry of the important aquatic organisms. They can be divided into capture fisheries, aquaculture, and fishery product processing, being subdivided into mariculture, aquaculture in fresh water, ornamental fisheries, or aquarium fish, and sport fisheries or recreational fisheries on the basis of objects and patterns of production. Extensive fish farming Fish culture may be classified into an extensive, semi-intensive, and intensive fish farming according to husbandry patterns and resource input, that is, whether the farming is based on natural food only, or whether it includes, additionally, more-or-less complete artificial feeding. The extensive fish farming means obtaining a quantity of fish corresponding to natural productivity at low inputs of labor, resources and capital per unit (m2, m3 or hm2), often without fertilization and unfeeding. For instance, coastal lagoons or inland lakes or reservoirs may be stocked with wild-caught fry or hatchery-reared juveniles which are managed as they grow by removing predators or natural enemies, whereas feed requirements are met by the natural supplies of animal and plant life in the lagoon, lakes or reservoirs with no supplementary feeding by the farmer. Fish ranching is one of the extensive farming systems. Intensive Fish Farming At the other extreme, intensive fish farming seeks to produce a maximum quantity of fish in a minimum of water and high economic profits per unit of water using modern techniques such as nutritional feed, water quality control and rational husbandry. The net cage fish culture and industrialized fish culture are the familiar examples of the intensive farming. Between these two extremes lie the majority of semi-intensive finfish-rearing system, for example s