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Glossary Of Fishery Terms
This is a glossary of terms used in fisheries, fisheries management and fisheries science. A * Abundance - is a measure of how many fish are in a population or a fishing ground. See relative abundance and absolute abundance. * Acoustic survey - a systematic gathering of information on fish availability and abundance using underwater sound. * Acoustical oceanography - the use of underwater sound to map underwater topography and the contents of the sea. * Aerial survey - a method of gathering information on surface fish movement and density by visual observation and photography from low-flying aircraft. * Aggregation - any grouping of fish, for whatever reason (or unknown reason) they are concentrating. See shoaling. * Agricultural runoff - surplus water from agricultural land, often draining into rivers and then into the sea, and often enriched with nutrients, sediment, and agricultural chemicals. * Alginate production - a gel substance extracted from brown algae and used in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisheries
Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both in freshwater waterbodies (about 10% of all catch) and the oceans (about 90%). About 500 million people worldwide are economically dependent on fisheries. 171 million tonnes of fish were produced in 2016, but overfishing is an increasing problem — causing declines in some populations. Because of their economic and social importance, fisheries are governed by complex fisheries management practices and legal regimes that vary widely across countries. Historically, fisheries were treated with a " first-come, first-served " approach, but recent threats by human overfishing and environmental issues have required increased regulation of fisheries to prevent conflict and increase profitable economic activity on the fishery. Modern jurisdicti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coble
The coble is a type of open traditional fishing boat which developed on the North East coast of England. The southernmost examples occur around Hull (although Cooke drew examples at Yarmouth, see his ''Shipping and Craft'' series of drawings of 1829); the type extends to Burnmouth just across the Scottish border. The distinctive shape of the boat — flat-bottomed and high- bowed — arose to cope with the particular conditions prevalent in this area. Flat bottoms allowed launching from and landing upon shallow, sandy beaches; an advantage in this part of the coast where the wide bays and inlets provided little shelter from stormy weather. However, fishermen required high bows to sail in the dangerous North Sea and in particular to launch into the surf and to land on the beaches. The design contains relics of Norse influence, though in the main it shows Dutch origin. A Scottish version of the coble, much shallower and beamier than the English type, serves for salmon-fishing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fishing Bait
Fishing bait is any substance used to attract and catch fish, e.g. on a fishing hook. Bait items are both selected from and placed within the environment to achieve enhanced prey capture success. Traditionally, fishing baits are natural fish food such as night-crawlers, insects, worms, and smaller bait fish that have been used for catching fish. Fishermen have also begun using processed food, plastic baits and more recently, bionic lures to attract fish. Despite the importance of fish's attraction to bait, the way fish react to different baits is quite poorly understood. The various techniques and bait that a fisher may choose is dictated mainly by the target species and by its habitat. Bait can be separated into two main categories: artificial baits and natural baits. The alternative of artificial and live baits frequently demonstrate similar efficiency. The overall bait type and size will affect the efficiency and results of catches when fishing. With these two common w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bait Fish
300px, Feeder Goldfish are common baitfish. Bait fish (or baitfish) are small-sized fish caught and used by anglers as bait to attract larger predatory fish, particularly game fish. Baitfish species are typically those that are common and breed rapidly, making them easy to catch and in abundant supply. Overview Examples of marine bait fish are anchovies, gudgeon, halfbeaks such as ballyhoo, and scad. Some larger fish such as menhaden, flying fish or ladyfish may be considered bait fish in some circles, depending on the size of the gamefish being pursued. Freshwater bait fish include minnows from the carp family (Cyprinidae), sucker family (Catostomidae), topminnows from the killifish suborder (Cyprinodontoidei), shad family (Clupeidae), sculpin of the order Scorpaeniformes and sunfish family (Centrarchidae), excluding black basses and crappies. Bait fish can be contrasted with forage fish. ''Bait fish'' is a term used particularly by recreational fishermen, although commer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catch Per Unit Effort
In fisheries and conservation biology, the catch per unit effort (CPUE) is an indirect measure of the abundance of a target species. Changes in the catch per unit effort are inferred to signify changes to the target species' true abundance. A decreasing CPUE indicates overexploitation, while an unchanging CPUE indicates sustainable harvesting. CPUE has a number of advantages over other methods of measuring abundance. It does not interfere with routine harvesting operations, and data are easily collected. The data are also easy to analyse, even for non-specialists, in contrast to methods based on transects. This means that decisions about stock management can also be made by the people doing the harvesting. The best practice is to standardise the effort employed (''e.g.'' number of traps or duration of searching), which controls for the reduction in catch size that often results from subsequent efforts. Although CPUE is a relative measure of abundance, it can be used to estimate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mariculture
Mariculture or marine farming is a specialized branch of aquaculture (which includes freshwater aquaculture) involving the cultivation of marine organisms for food and other animal products, in enclosed sections of the open ocean ( offshore mariculture), fish farms built on littoral waters ( inshore mariculture), or in artificial tanks, ponds or raceways which are filled with seawater ( onshore mariculture). An example of the latter is the farming of marine fish, including finfish and shellfish like prawns, or oysters and seaweed in saltwater ponds. Non-food products produced by mariculture include: fish meal, nutrient agar, jewellery (e.g. cultured pearls), and cosmetics. Methods Algae Shellfish Similar to algae cultivation, shellfish can be farmed in multiple ways: on ropes, in bags or cages, or directly on (or within) the intertidal substrate. Shellfish mariculture does not require feed or fertilizer inputs, nor insecticides or antibiotics, making shellfish aquacult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Farming
upright=1.3, Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye">mariculture.html" ;"title="Salmon farming in the sea (mariculture">Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye, Scotland Fish farming or pisciculture involves commercial animal husbandry, breeding of fish, usually for food, in fish tanks or artificial pen (enclosure), enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environment. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species produced in fish farming are carp, catfish, salmon and tilapia. Global demand is increasing for dietary fish protein, which has resulted in widespread overfishing in wild ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquaculture
Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. lotus). Aquaculture involves cultivating freshwater, brackish water and saltwater populations under controlled or semi-natural conditions, and can be contrasted with commercial fishing, which is the harvesting of wild fish. Mariculture, commonly known as marine farming, refers specifically to aquaculture practiced in seawater habitats and lagoons, opposed to in freshwater aquaculture. Pisciculture is a type of aquaculture that consists of fish farming to obtain fish products as food. Aquaculture can also be defined as the breeding, growing, and harvesting of fish and other aquatic plants, also known as farming in water. It is an environmental source of food and commercial product which help to improve healthier habitats and used to recon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Krill
Antarctic krill (''Euphausia superba'') is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their pelagic (open ocean) life cycle. It grows to a length of , weighs up to , and can live for up to six years. It is a key species in the Antarctic ecosystem and in terms of biomass, is one of the most abundant animal species on the planet (approximately 500 million tons, corresponding to 300 to 400 trillion individuals). Life cycle The main spawning season of Antarctic krill is from January to March, both above the continental shelf and also in the upper region of deep sea oceanic areas. In the typical way of all krill, the male attaches a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Convergence
The Antarctic Convergence or Antarctic Polar Front is a marine belt encircling Antarctica, varying in latitude seasonally, where cold, northward-flowing Antarctic waters meet the relatively warmer waters of the sub-Antarctic. Antarctic waters predominantly sink beneath the warmer subantarctic waters, while associated zones of mixing and upwelling create a zone very high in marine productivity, especially for Antarctic krill. This line, like the arctic tree line, is a natural boundary rather than an artificial one, such as the borders of nations and time zones. It not only separates two hydrological regions, but also separates areas of distinctive marine life and climates. The Arctic has no similar boundary because of the large bodies of land contiguous with the northern polar region. History The Antarctic Convergence was first crossed by Anthony de la Roché in 1675, and described by Edmond Halley in 1700. Location The Antarctic Convergence is a zone approximately wide, v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain shape, and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoxia (environmental)
Hypoxia refers to low oxygen conditions. Normally, 20.9% of the gas in the atmosphere is oxygen. The partial pressure of oxygen in the atmosphere is 20.9% of the total barometric pressure. In water, oxygen levels are much lower, approximately 7 ppm or 0.0007% in good quality water, and fluctuate locally depending on the presence of photosynthetic organisms and relative distance to the surface (if there is more oxygen in the air, it will diffuse across the partial pressure gradient). Atmospheric hypoxia Atmospheric hypoxia occurs naturally at high altitudes. Total atmospheric pressure decreases as altitude increases, causing a lower partial pressure of oxygen, which is defined as hypobaric hypoxia. Oxygen remains at 20.9% of the total gas mixture, differing from hypoxic hypoxia, where the percentage of oxygen in the air (or blood) is decreased. This is common in the sealed burrows of some subterranean animals, such as blesmols. Atmospheric hypoxia is also the basis of altitude tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
