tailieunhanh - Manual on the Production and Use of Live Food for Aquaculture - Phần 9

Tham khảo tài liệu 'manual on the production and use of live food for aquaculture - phần 9', nông - lâm - ngư, ngư nghiệp phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | . Wild zooplankton . Production of copepods . Mesocosm systems . Literature of interest . Wild zooplankton . Introduction . Collection from the wild . Collection techniques . Zooplankton grading . Transport and storage of collected zooplankton . Introduction Zooplankton is made up of small water invertebrates feeding on phytoplankton. Even though plankton means passively floating or drifting some representatives of zooplankton may be strong swimmers. The yearly plankton cycle consists of various phytoplankton species blooming in response to a particular sequence of changes in temperature salinity photoperiod and light intensity nutrient availability and a consequent bloom of zooplankton populations. Phytoplankton and zooplankton populations are therefore intimately linked in a continuous cycle of bloom and decline that has evolved and persisted throughout millions of years of evolution. Studies on the stomach contents of fish larvae caught in their natural environment clearly show that almost no fish species can be regarded as strongly stenophagic specialized in feeding on only a few or just one zooplankton species though some specialization may occur . due to size limitations for ingestion . There are three obvious advantages of using wild zooplankton as a live food source for the cultivation of the early larval stages of shrimp or fish species As it is the natural food source it may be expected that its nutritional composition maximally covers the nutritional requirements of the predator larvae especially with respect to essential fatty acids and free amino acids Tables and . The diversified composition of wild zooplankton in terms of species variety as well as ontogenetic stages assures that optimal sizes of prey organisms will be available and efficient uptake by the predator is possible at any time during the larval rearing. Depending on the harvesting potential nearby the hatchery facility there .