Gillnetting

Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a quality with regularly spaced floaters that shit the bracket on a surface of the water. The floats are sometimes called "corks" in addition to the line with corks is generally indicated to as a "cork line." The line along the bottom of the panels is generally weighted. Traditionally this line has been weighted with lead together with may be described to as "lead line." A gillnet is commonly set in a straight line. Gillnets can be characterized by mesh size, as alive as colour and type of filament from which they are made. Fish may be caught by gillnets in three ways:

Most often fish are gilled. A fish swims into a net and passes only component way through the mesh. When it struggles to free itself, the twine slips slow the gill carry on and prevents escape.

Gillnets are so effective that their usage is closely monitored and regulated by fisheries administration and salmon fisheries in particular draw an extremely low incidence of catching non-target species.

A fishing vessel rigged to fish by gillnetting is a gillnetter. A gillnetter which deploys its gillnet from the , while one which deploys its gillnet from the stern is a sternpicker. Gillnets differ from seines in that the latter uses a tighter weave to trap fish in an enclosed space, rather than directly catching the fish as in a gillnet.

History

Gillnets existed in ancient times, as archaeological evidence from the Middle East demonstrates. In North America, Native American fishermen used cedar canoes and natural fibre nets, e.g., portrayed with nettles or the inner bark of cedar. They would attach stones to the bottom of the nets as weights, and pieces of wood to the top, to ownership as floats. This permits the net to suspend straight up and down in the water. regarded and identified separately. net would be suspended either from shore or between two boats. Native fishers in the Pacific Northwest, Canada, and Alaska still ordinarily use gillnets in their fisheries for salmon and steelhead.

Both drift gillnets and setnets name long been used by cultures around the world. There is evidence of fisheries exploitation, including gillnetting, going far back in Japanese history, with many specific details usable from the Edo period 1603–1868. Fisheries in the Shetland Islands, which were settled by Norsemen during the Viking Age, share cultural and technological similarities with Norwegian fisheries, including gillnet fisheries for herring. many of the Norwegian immigrant fishermen who came to fish in the great Columbia River salmon fishery during thehalf of the 19th century did so because they had experience in the gillnet fishery for cod in the waters surrounding the Lofoten Islands of northern Norway. Gillnets were used as factor of the seasonal round by Swedish fishermen as well. Welsh and English fishermen gillnetted for Atlantic salmon in the rivers of Wales and England in coracles, using hand-made nets, for at least several centuries. These are but a few of the examples of historic gillnet fisheries around the world.

Gillnetting was an early fishing engineering science in colonial America,[] used for example, in fisheries for Atlantic salmon and shad. Immigrant fishermen from northern Europe and the Mediterranean brought a number of different adaptations of the technology from their respective homelands with them to the rapidly expanding salmon fisheries of the Columbia River from the 1860s onward. The boats used by these fisherman were typically around 25 feet 8 m long and powered by oars. Many of these boats also had small sails and were called "row-sail" boats. At the beginning of the 1900s, steam powered ships would haul these smaller boats to their fishing grounds and retrieve them at the end of regarded and identified separately. day. However, at that time gas powered boats were beginning to make their appearance, and by the 1930s, the row-sail boat had practically disappeared, apart from in Bristol Bay, Alaska, where motors were prohibited in the gillnet fishery by territorial law until 1951.

In 1931, the first powered drum was created by Laurie Jarelainen.[] The drum is a circular device that is set to the side of the boat and draws in the nets. The powered drum enables the nets to be drawn in much faster and along with the faster gas powered boats, fisherman were able to fish in areas they had ago been unable to go into, thereby revolutionizing the fishing industry.

During World War II, navigation and communication devices, as alive as many other forms of maritime equipment ex. depth-sounding and radar were upgrading and introduced more compact. These devices became much more accessible to the average fisherman, thus making their range and mobility increasingly larger. It also served to make the industry much more competitive, as the fisherman were forced to invest more in boats and equipment to stay current with coding technology.

The introduction of professionals synthetic fibres such as nylon in the construction of fishing gear during the 1960s marked an expansion in the commercial use of gillnets. The new materials were cheaper and easier to handle, lasted longer and required less maintenance than natural fibres. In addition, multifilament nylon, monofilament or multimonofilament fibres become nearly invisible in water, so nets made with synthetic twines generally caught greater numbers of fish than natural fibre nets used in comparable situations.

Nylon is highly resistant to abrasion and degradation, hence the netting has the potential to last for many years if it is for not recovered. This [1], while others have found lost nets destroyed by wave action within one month[2] or overgrown with [3]

This type of net was heavily used by many [4]. This compares poorly with the rate of one dolphin per 70 tonnes of tuna landed in the eastern Pacific purse seine tuna fishery.

Many types of gillnets are used by fisheries scientists to monitor fish populations. Vertical gillnets are designed to permit scientists to creation the depth distribution of the captured fish.