BIO 410- Fisheries and Aquaculture

The term “fish” most precisely describes any non-tetrapod craniates (that is an animal with a skull and in most cases a backbone) that have gills throughout life and whose limbs, if any, are in the shape of fins. Unlike groupings such as birds and mammals, fish are not a single clade but a paraphyletic collection of taxa, including hagfishes, lampreys, sharks and rays, ray-finned fishes, coelacanths and lungfishes. A typical fish is ectothermic, has a streamlined body for rapid swimming, extracts oxygen from water using gills or uses an accessory breathing organ to breathe atmospheric oxygen, has two sets of paired fins, usually one of two (rarely three) dorsal fins, an anal fin, and a tail fin, has jaws, has skin that is usually covered with scales, and lays eggs. Fish display a great variety of forms and are adapted to the environment in which they live in many ways. There are two groups of fish in the class that differs in the composition of their bones. These are the bonyfish(fish with well developed hard bones) like tilapia, catfish and the cartilaginous(fish with soft flexible fibrous bones called cartilage) fish like the shark. Fish serve as a major source of food to other living beings. Humans consume a lot of fish. Fish by-products are used in animal rations as a good protein source.