Fish species of commercial importance
Fish are relevant organisms from many standpoints including food production, commercial and sport fisheries, ornamental animals, as well as laboratory models for research in several disciplines, e.g. toxicology, pharmacology, physiology, genetics, and ecology. Of all animal species farmed, only 30 produce more than 200,000 tons and 22 of these are fish (FAO, 2007). However, production differs from one region to another, and a wide range of species is farmed under different systems, including diadromous fish (salmonids), marine fish (seabass, turbot, halibut and cod) and freshwater fish (tilapia, carp and catfish). Together, salmonids, tilapia and carp make up ~25% of the 50 million tons of world aquaculture production (FAO, 2012). The rapid development of fish farming techniques and innovative aquaculture technologies have contributed to increasingly larger production of species for both food and ornamental purpose, as well as provide a regular supply of specimens for repopulation, laboratory research or monitoring systems. Today aquaculture caters to the worldwide demand for ornamental fish, and more importantly, to the animal protein market for human consumption. By 2010 it contributed with ~ 47% of all fisheries output for human consumption, an impressive increase from the 5% in the 1960’s (FAO, 2012), with freshwater species producing the greatest volume. Various fish species representing different groups have been considered for this manual, based on their economical relevance, interest to farming or laboratory use and importance to commercial or sport fishing. A brief description of the groups included in this work follows.