Fishing techniques

Fishing techniques are methods for catching fish. The term may also be applied to methods for catching other aquatic animals such as molluscs (shellfish, squid, octopus) and edible marine invertebrates.
Fishing techniques include hand-gathering, spearfishing, netting, angling and trapping. Recreational, commercial and artisanal fishers use different techniques, and also, sometimes, the same techniques. Recreational fishers fish for pleasure or sport, while commercial fishers fish for profit. Artisanal fishers use traditional, low-tech methods, for survival in developing countries, and as a cultural heritage in other countries. Mostly, recreational fishers use angling methods and commercial fishers use netting methods.
There is an intricate link between various fishing techniques and knowledge about the fish and their behaviour including migration, foraging and habitat. The effective use of fishing techniques often depends on this additional knowledge. Which techniques are appropriate is dictated mainly by the target species and by its habitat.
Fishing techniques can be contrasted with fishing tackle. Fishing tackle refers to the physical equipment that is used when fishing, whereas fishing techniques refers to the manner in which the tackle is used when fishing.
It is possible to harvest many sea foods with minimal equipment by using the hands. Gathering seafood by hand can be as easy as picking shellfish or kelp up off the beach, or doing some digging for clams or crabs. The earliest evidence for shellfish gathering dates back to a 300,000-year-old site in France called Terra Amata. This is a hominid site as modern Homo sapiens did not appear in Europe until around 50,000 years ago.
Spearfishing is an ancient method of fishing conducted with an ordinary spear or a specialized variant such as a harpoon, trident, arrow or eel spear. Some fishing spears use slings (or rubber loops) to propel the spear.
Fishing nets are meshes usually formed by knotting a relatively thin thread. About 180 AD the Greek author Oppian wrote the Halieutica, a didactic poem about fishing. He described various means of fishing including the use of nets cast from boats, scoop nets held open by a hoop, and various traps "which work while their masters sleep".
Netting is the principal method of commercial fishing, though longlining, trolling, dredging and traps are also used.
Angling is a method of fishing by means of an "angle" (fish hook). The hook is attached to a line, and is sometimes weighed down by a sinker so it sinks deeper in the water. This is the classic "hook, line and sinker" arrangement, used in angling since prehistoric times. The hook is usually dressed with lures or baits such as earthworm, doughball and bait fish.
Additional arrangements include the use of a fishing rod, which can be fitted with a reel, and functions as a delivery mechanism for casting the line. Other delivery methods for projecting the line include fishing kites and cannons, kontiki rafts and remote controlled devices. Floats can also be used to help set the line or function as bite indicators. The hook can be dressed with lures or bait. Angling is the principal method of sport fishing, but commercial fisheries also use angling methods involving multiple hooks, such as longlining or commercial trolling.
Line fishing is fishing with a fishing line, but not using rods. A fishing line is any cord made for fishing. Important parameters of a fishing line are its length, material, and weight (thicker, sturdier lines are more visible to fish). Factors that may determine what line an angler chooses for a given fishing environment include breaking strength, knot strength, UV resistance, castability, limpness, stretch, abrasion resistance, and visibility.
Modern fishing lines are usually made from artificial substances. The most common type is monofilament, made of a single strand. There are also braided fishing lines and thermally fused superlines.
Angling with fishing rods give more control of the fishing line, and allows the bait/lure to be launched much farther than hand-throwing can reach. The rod is usually fitted with a fishing reel which functions as a mechanism for storing, retrieving and paying out the line. Floats may also be used, and can function as bite indicators. The hook can be dressed with lures or baits.
Traps are culturally almost universal and seem to have been independently invented many times. There are essentially two types of trap, a permanent or semi-permanent structure placed in a river or tidal area and pot-traps that are baited to attract prey and periodically lifted.
Destructive fishing practices are practices that easily result in irreversible damage to aquatic habitats and ecosystems. Many fishing techniques can be destructive if used inappropriately, but some practices are particularly likely to result in irreversible damage. These practices are mostly, though not always, illegal. Where they are illegal, they are often inadequately enforced. Some examples are:
Dynamite or blast fishing is done easily and cheaply with dynamite or homemade bombs made from locally available materials. Fish are killed by the shock from the blast and are then skimmed from the surface or collected from the bottom. The explosions indiscriminately kill large numbers of fish and other marine organisms in the vicinity and can damage or destroy the physical environment. Explosions are particularly harmful to coral reefs. Blast fishing is also illegal in many waterways around the world.
Bottom trawling is trawling (towing a trawl, which is a fishing net) along the sea floor. It is also referred to as "dragging". The scientific community divides bottom trawling into benthic trawling and demersal trawling. Benthic trawling is towing a net at the very bottom of the ocean and demersal trawling is towing a net just above the benthic zone. Bottom trawling targets both bottom-living fish (groundfish) and semi-pelagic species such as cod, squid, shrimp, and rockfish.
Bottom fishing has operated for over a century on heavily fished grounds such as the North Sea and Grand Banks. While overfishing has long been recognised as causing major ecological changes to the fish community on the Grand Banks, concern has been raised more recently about the damage which benthic trawling inflicts upon seabed communities. A species of particular concern is the slow growing, deep water coral Lophelia pertusa. This species is home to a diverse community of deep sea organisms, but is easily damaged by fishing gear. On 17 November 2004, the United Nations General Assembly urged nations to consider temporary bans on high seas bottom trawling.
Cyanide fishing is a method of collecting live fish mainly for use in aquariums, which involves spraying a sodium cyanide mixture into the desired fish's habitat in order to stun the fish. The practice hurts not only the target population, but also many other marine organisms, including coral and thus coral reefs.
Recent studies have shown that the combination of cyanide use and stress of post capture handling results in mortality of up to 75% of the organisms within less than 48 hours of capture. With such high mortality numbers, a greater number of fish must be caught in order to offset post-catch death.
Muro-ami is a destructive artisan fishing method employed on coral reefs in Southeast Asia, traditionally in Myanmar. An encircling net is used with pounding devices, such as large stones fitted on ropes that are pounded onto the coral reefs. They can also consist of large heavy blocks of cement suspended above the sea by a crane fitted to the vessel. The pounding devices are repeatedly lowered into the area encircled by the net, smashing the coral into small fragments in order to scare the fish out of their coral refuges. The "crushing" effect on the coral heads has been described as having long-lasting and practically totally destructive effects.
Ancient remains of spears, hooks and fish net have been found in ruins of the Stone Age. The people of the early civilization drew pictures of nets and fishing lines in their arts (Parker 2002). Early hooks were made from the upper bills of eagles and from bones, shells, horns and plant thorns. Spears were tipped with the same materials, or sometimes with flints. Lines and nets were made from leaves, plant stalk and cocoon silk. Literature on the indigenous fishing practices is very scanty. Baines (1992) documented traditional fisheries in the Solomon Islands. Use of the herbal fish poisons in catching fishes from fresh water and sea documented from New Caledonia (Dahl 1985). John (1998) documented fishing techniques and overall life style of the Mukkuvar fishing Community of Kanyakumari district of Tamil Nadu, India. Tribal people using various plants for medicinal and various purposes (Rai et al. 2000; Singh et al. 1997; Lin 2005) extends the use notion for herbal fish stupefying plants. Use of the fish poisons is very old practice in the history of human kind. In 1212, King Frederick II prohibited the use of certain plant piscicides, and by the 15th century similar laws had been decreed in other European countries as well (Wilhelm 1974). All over the globe, indigenous people use various fish poisons to kill the fishes, documented in America (Jeremy 2002) and among Tarahumara Indian (Gajdusek 1954).