Importance of Copepoda in Freshwater Aquaculture

In recent decades, aquaculture has become an increasingly important part of the world economy. Other than marketing concerns, the biggest challenge facing fish farmers is to control the many complex abiotic and biotic factors that influence the success of fish rearing. An example of the complexity involved in managing aquatic systems is the need to control copepod populations by manipulating the pond environment. Copepods play major roles in pond ecosystems, serving as 1) food for small fish, 2) micropredators of fish and other organisms, 3) fish parasites, 4) intermediate hosts of fish parasites, and 5) hosts and vectors of human diseases. Planktonic animals, especially rotifers, cladocerans, and copepods of the order Cyclopoida are the most important food items in freshwater aquaculture, and copepod nauplii are especially valuable for feeding fry. Copepods used as natural food are either cultured or collected from natural water bodies. Adult and advanced copepodid stages of cyclopoids are micropredators that target early life stages of cyprinids (Cyprinidae). Other copepods in aquaculture are fish parasites. The most common adult copepod parasites of freshwater fishes are Lernaea cyprinacea, Ergasilus sieboldi (and related species), Salmincola californiensis, S. edwardsii, Achtheres percarum, Tracheliastes maculatus, and Caligus lacustris. In addition, copepodids of Lernaea and chalimus larvae of Achtheres and Salmincola attach to gill filaments and cause epithelial hyperplasia and may be indirectly responsible for fish-kills. Copepods are also intermediate hosts for important fish parasites, including tapeworms and nematodes. Damage from these parasites may lead to fish mortalities or reduce the market value of the fish products. Finally, copepods serve as intermediate hosts for parasites that infect humans and can serve as vectors of serious human diseases like cholera. http://www.sinica.edu.tw/zool/ zoolstud/43.2/193.pdf.