วันเสาร์ที่ 27 ตุลาคม พ.ศ. 2555

Ecology and life history



Although most species live in inshore and estuarine waters, 29 species spend their entire life cycles in freshwater. These species are found in disjunct tropical regions of South America (one species), Central Africa (three species) and Southeast Asia (25 species).


Natural defenses :
A pufferfish pressing its mouth against a camera's lens at Big Island of Hawaii
The puffer's unique and distinctive natural defenses help compensate for its slow locomotion. It moves by combining pectoral, dorsal, anal, and caudal fins. This makes it highly maneuverable, but very slow, and therefore a comparatively easy predation target. Its 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 its usual movements. The puffer's excellent eyesight, combined with this speed burst, is the first and most important defense against predators. Its backup defense mechanism, used if successfully pursued, is to fill its extremely elastic stomach with water (or air when outside the water) until it is 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 do not 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 stomachs 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.
Not all puffers are necessarily poisonous; Takifugu oblongus, for example, is a fugu puffer that is not poisonous, and toxin level varies wildly even in fish that are. A puffer's neurotoxin is not necessarily as toxic to other animals as it is to humans, and puffers are eaten routinely by some species of fish, such as lizardfish[3] and tiger sharks.Also, Japanese fish farmers have grown nonpoisonous puffers by controlling their diet.



Puffers are able to move their eyes independently, and many species can change the color or intensity of their patterns in response to environmental changes. In these respects, they are somewhat similar to the terrestrial chameleon. Although most puffers are drab, many have bright colors and distinctive markings, and make no attempt to hide from predators. This is likely an example of aposematism.


Reproduction :
Blackspotted puffer, Arothron nigropunctatus
Many marine puffers have a pelagic, or open-ocean, life stage. Spawning occurs after males slowly push females to the water surface or join females already present. The eggs are spherical and buoyant. Hatching occurs after roughly four days. The fry are tiny, but under magnification have a shape that is usually reminiscent of a pufferfish. They have a functional mouth and eyes, and must eat within a few days. Brackish water puffers may breed in bays in a similar manner to marine species, or may breed more similarly to the freshwater species, in cases where they have moved far enough upriver.
Reproduction in freshwater species varies quite a bit. The dwarf puffers court with males following females, possibly displaying the crests and keels unique to this subgroup of species. After the female accepts his advances, she will lead the male into plants, moss or another form of cover, where she can release eggs for fertilization. The male may help her by rubbing against her side. This has been observed in captivity, and they are the only commonly captive-spawned puffer species.

Target-group puffers have also been spawned in aquariums, and follow a similar courting behavior, minus the crest/keel display. However, eggs are laid on a flat piece of slate or other smooth hard material, to which they adhere. The male will guard them until they hatch, carefully blowing water over them regularly to keep the eggs healthy. His parenting is finished when the young hatch, and the fry are on their own.
Information on breeding of specific species is very limited. T. nigroviridis, the green-spotted puffer, has recently been artificially spawned under captive conditions. It is believed to spawn in bays in a similar manner to saltwater species, as their sperm were found to be motile only at full marine salinities, but actual wild breeding has never been observed.

In 2012, male pufferfish were documented carving large geometric, circular structures in the seabed sand in Amami Ōshima, Japan. The structures apparently serve to attract females and provide a safe place for them to lay their eggs.

Thank For WIGI.

วันพุธที่ 18 กรกฎาคม พ.ศ. 2555

Fisherman


          A fisherman or fisher is someone who captures fish and other animals from a body of water, or gathers shellfish. Worldwide, there are about 38 million commercial and subsistence fishermen and fish farmers.The term can also be applied to recreational fishermen and may be used to describe both men and women. Fishing has existed as a means of obtaining food since the Mesolithic period.

Thank for Info : http://en.wikipedia.org

fishing lures Types

           There are many types of fishing lures. They are all manufactured in different ways to resemble prey for the fish in most cases, but are sometimes engineered to appeal to a fishes sense of territory, curiosity or aggression. Most lures are made to look like dying, injured, or fast moving fish. They include the following types 



  •  A jig is a weighted hook with a lead head opposite the sharp tip. They are often covered with a minnow or crawfish or even a plastic worm to get the fish's attention. The angler moves the rod to make the jig move.
Deep water jigs used in saltwater fishing consist of a large metallic weight, which gives the impression of the body of the baitfish, which has a hook attached via a short length of kevlar usually to the top of the jig. These types of jigs can be fished in water depths down to 300 metres.
  • Surface lures are also known as top water lures, poppers and stickbaits. They float and resemble prey that is on top of the water. They can make a popping sound from a concave-cut head, a burbling sound from "side fins" or scoops or a buzzing commotion from one or several propellers. A few have only whatever motion the fisherman applies through the rod itself, though if skillfully used, they can be very effective.
  • Spoon lures are made to resemble the inside of a table spoon. They flash in the light while wobbling or darting due to their shape, and attract fish.
  • Plugs are also known as crankbaits or minnows. These lures have a fishlike body shape and they are run through the water where they can make a variety of different movements caused by instability due to the bib at the front under the head.
  • Artificial flies are designed to resemble all manner of fish prey and are used with a fly rod and reel in fly fishing.
  • Soft plastic baits/lures is a general category of lures that are made of plastic or rubber, and are designed to resemble fish, crabs, squid, worms, lizards, frogs, leeches and other creatures.
  • Spinnerbait are pieces of wire bent at about a 60 degree angle with a hook on the lower end and a flashy spinner mechanism on the upper end.
  • Swimbait is a form of soft plastic bait/lure that resembles an actual baitfish. It can be retrieved like a plug/minnow lure. Some of these have a swimming, paddle, tail. The development in the finishes in these types of plastic lures have meant that the finishes achieved now look more like a baitfish than ever before.


          Fishing lures can be made of wood, plastic, rubber, metal, cork, and materials like feathers, animal hair, string, tinsel and others. They can have many moving parts or no moving parts. They can be retrieved fast or slow. Some of the lures can be used by alone, or with another lure.
         One advantage of use of artificial lures is a reduction in use of bait. This contributes to resolving one of the marine environment's more pressing problems; the undermining of marine food webs by overharvesting "bait" species which tend to occur lower in the food chain. Another advantage of lures is that their use promotes improved survival of fish during catch and release fishing. This is because lures reduce the incidence of deep hooking which has been correlated to fish mortality in many studies. Mortality by swallowing hooks is mostly caused by the handling stress and damage resulting from removing the hook from the gut or throat. The best course of action when a fish is gut-hooked is to leave the hook and cut the line as soon as possible. Hooks will then be encapsulated or evacuated from the body. Use of non corroding steel is not recommended because a corroding hook will be easier to for the fish to expel.

Thank for Info : http://en.wikipedia.org

วันพฤหัสบดีที่ 12 กรกฎาคม พ.ศ. 2555

Plug (fishing)


          Plugs are a popular type of hard-bodied fishing lure. They are widely known by a number of other names depending on the country and region. Such names include crankbaitwobblerminnowshallow-diver and deep-diver. The term minnow is usually used for long, slender, lures that imitate baitfish, while the term plug is usually used for shorter, deeper-bodied lures which imitate deeper-bodied fish, frogs and other prey. Shallow-diver and deep-diver refer to the diving capabilities of the lure, which depends on the size of the lip and lure buoyancy.


Thank for Info : http://en.wikipedia.org

Fishing rod


          fishing rod or a fishing pole is a tool used to catch fish, usually in conjunction with the pastime of angling, and can also be used in competition casting. (Sustenance and commercial fishing usually involve nets). A length of fishing line is attached to a long, flexible rod or pole: one end terminates in a hook for catching the fish. A 'fishing pole' is a simple pole or stick for suspending a line (normally fastened to the tip), with a hooked lure or bait. They are most commonly made of fiberglass, carbon fiber, graphite or, classically, bamboo, and are the only fishing levers properly referred to as "poles". In contrast, 'fishing rod' refers to a more sophisticated casting tool fitted with line guides and a reel for line stowage. Fishing rods vary in action as well as length, and can be found in sizes between 24 inches and 20 feet. The longer the rod, the greater the mechanical advantage in casting.


Thank for Info : http://en.wikipedia.org

วันอังคารที่ 10 กรกฎาคม พ.ศ. 2555

Surface lure

Surface lure

          A surface lure is a fishing lure designed to waddle, pop, lock, drop, pulse, twitch or fizz across the surface of the water as it is retrieved, and in doing so imitate surface prey for fish such as mice, lizards, frogs, cicadas, moths and small injured fish. A typical surface lure has a solid body made out of wood or plastic, carries one or two treble hooks, and has an eyelet at the front of the lure body to attach the fishing line. Waddlers get their action from a scooped metal dish attached to the front of the lure body. Poppers get their action from a cupped face carved or molded into the front of the lure body. Fizzers get their action both from the fisherman manipulating the lure with the fishing rod and from one or more blades attached to the lure body, that spin when the lure is pulled and create a fizzing noise said to imitate the buzzing wings of a drowning insect.
Sizeable fish can create a sudden, noisy and spectacular explosion when they take a surface lure, usually giving the fisherman a fright in the process. Catching fish on surface lures is therefore considered a fairly exciting form of fishing.

Thank for Info : http://en.wikipedia.org

Fishing

Fishing
          Fishing is the activity of trying to catch fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering,spearing, netting, angling and trapping.
The term fishing may be applied to catching other aquatic animals such as molluscs, cephalopods, crustaceans, and echinoderms. The term is not normally applied to catching farmed fish, or to aquatic mammals, such as whales, where the term whaling is more appropriate.
          According to FAO statistics, the total number of commercial fishermen and fish farmers is estimated to be 38 million. Fisheries and aquaculture provide direct and indirect employment to over 500 million people.In 2005, the worldwide per capita consumption of fish captured from wild fisheries was 14.4 kilograms, with an additional 7.4 kilograms harvested from fish farms. In addition to providing food, modern fishing is also a recreational pastime.

Thank for Info : http://en.wikipedia.org