Sabtu, 15 Januari 2011


1.The Meaning of Fish
Fish is a member of the vertebrate poikilotermik (cold blooded) [1] that live in water and breathe with gills. Fish is the most diverse vertebrate species of more than 27.000 worldwide. In taxonomy, fish belong to a paraphyletic group kekerabatannya relationship is still debated; usually fish without jaws were divided into fish (class Agnatha, 75 species including lampreys and fish Hags), cartilaginous fish (class Chondrichthyes, 800 species including sharks and rays), and the rest classified as hard bony fish (class Osteichthyes). Fish in various regional languages is called Iwak (jv, Bjn), jukut (vkt).
Fish has a variety of sizes, ranging from whale sharks measuring 14 meters (45 ft) to stout infantfish that only 7 mm (about 1 / 4 inch). There are some aquatic animals that are often regarded as the “fish”, such as whales, fish, squid and dugongs, which are not classified as fish. 
2. Classification
Fish is parafiletik group: this means, every class that contains all the fish will also include non-fish tetrapod. On this basis, groupings such as the Class Pisces, as in the past, no longer fit for use.
These are units that include all vertebrate fish commonly known as:
* Subclass Pteraspidomorphi (not berahang primitive fish)
o Class Thelodonti
o Class Anaspida
o (no status) Cephalaspidomorphi (not berahang primitive fish)
(no status) Hyperoartia
# Petromyzontidae (lampreys)
o Class Galeaspida
o Class Pituriaspida
o Class Osteostraci
* Infrafilum Gnathostomata (vertebrates berahang)
o Class Placodermi (armored fishes, extinct)
o Class Chondrichthyes (cartilaginous fish: sharks, rays)
o Class Acanthodii (spiny sharks, extinct)
* superclass Osteichthyes (bony fish true: cover nearly all important fish present)
o Class Actinopterygii (fan-finned fishes)
o Class Sarcopterygii (fleshy fins of fish / lobe finned fish)
Subclass Coelacanthimorpha (coelacanth)
Subclass Dipnoi (lung fishes)

3. Fish Ecology
Fish can be found in almost all the “puddle” of water that are large both freshwater, brackish water or salt water at varying depths, from near surface to several thousand meters below the surface. However, hyper-saline lakes like the Great Salt Lake do not support fish. There are several species of fish cultivated for maintained to be exhibited in the aquarium.
Fish are an important food source. Other aquatic animals, such as molluscs and crustaceans also sometimes regarded as a fish when used as a food source. Catch fish for food in small quantities or sports are often referred to as fishing. Results of fishing the world each year approximately 100 million tons.
Overfishing is a term in English to explain the overfishing. This phenomenon is a threat to various species of fish. On May 15, 2003, the journal Nature reported that all species of large marine fish have been caught over the systematic until the number is less than 10% of existing total in 1950. The author article in the journal suggests a drastic reduction in fishing and marine habitat reservations on the world.