Saturday, January 1, 2011
January 1, 2011 : Puffer Fish
Tetraodontidae is a family of primarily marine and estuarine fish of the Tetraodontiformes order. The family includes many familiar species which are variously called pufferfish, balloonfish, blowfish, bubblefish, globefish, swellfish, toadfish, toadies, honey toads, and sea squab. They are morphologically similar to the closely related porcupinefish, which have large external spines (unlike the thinner, hidden spines of Tetraodontidae, which are only visible when the fish has puffed up). The scientific name refers to the four large teeth, fused into an upper and lower plate, which are used for crushing the shells of crustaceans and mollusks, their natural prey.
Puffer fish are generally believed to be the second–most poisonous vertebrate in the world, after the Golden Poison Frog. Certain internal organs, such as liver, and sometimes their skin are highly toxic to most animals when eaten, but nevertheless the meat of some species is considered a delicacy in Japan (as 河豚, pronounced as fugu), Korea (as bok), and China (as 河豚 he2 tun2) when prepared by chefs who know which part is safe to eat and in what quantity.
The tetraodontidae contains at least 121 species of puffers in 20 genera. They are most diverse in the tropics and relatively uncommon in the temperate zone and completely absent from cold waters. They are typically small to medium in size, although a few species can reach lengths of greater than 100 centimetres (39 in).
The puffer's unique and distinctive natural defenses help compensate for their slow locomotion. Puffers move by combining pectoral, dorsal, anal, and caudal fins. This makes them highly maneuverable but very slow, and therefore comparatively easy predation targets. Their tail fin is mainly used as a rudder, but it can be used for a sudden evasive burst of speed that shows none of the care and precision of their usual movements. The puffers excellent eyesight combined with this speed burst is the first and most important defense against predators. Their back up defense mechanism, used if they are successfully pursued, is to fill their extremely elastic stomachs with water (or air when outside the water) until they are much larger and almost spherical in shape. Even if they are not visible when the puffer is not inflated, all puffers have pointed spines, so a hungry predator may suddenly find itself facing an unpalatable pointy ball rather than a slow, tasty fish. Predators which don't heed this warning (or who are "lucky" enough to catch the puffer suddenly, before or during inflation) may die from choking, and predators that do manage to swallow the puffer may find their stomaches full of tetrodotoxin, making puffers an unpleasant, possibly lethal, choice of prey. This neurotoxin is found primarily in the ovaries and liver, although smaller amounts exist in the intestines and skin, as well as trace amounts in muscle. It does not always have a lethal effect on large predators, such as sharks, but it can kill humans.