Important Palegic Fishes

marine fisheries

1. NANAJI DESHMUKH VETERINARY SCIENCE UNIVERSITY, JABALPUR COLLEGE OF FISHERY SCIENCE JABALPUR SUBJECT- MARINE FISHERIES TOPIC- IMPORTANT PELAGIC FISHES

2. Pelagic fish, by definition, are found near the ocean surface or in middle depths. As a result, pelagic fisheries must search larger volumes than demersal fisheries. However, most pelagic fish species exhibit behaviours that increase their catchability. The most import characteristic is shoaling, in which individuals of the same species form and travel in aggregations. Several pelagic species also exhibit clear patterns of vertical migration, often staying deep in the water column, or near bottom, by day but migrating to surface waters at dusk. In some cases fishers have used techniques such as artificial light sources to enhance shoaling behaviour and improve fishing. PELAGIC FISHERIES

3. The marine  pelagic  environment is the largest aquatic habitat on Earth, occupying 1,370 million cubic kilometres (330 million cubic miles), and is the habitat for 11% of known  fish  species. The  oceans  have a mean depth of 4000 metres. About 98% of the total water volume is below 100 metres (330 ft), and 75% is below 1,000 metres (3,300 ft). CONTINUED..

4. Marine pelagic fish can be divided into- 1.Pelagic coastal fish and 2.Oceanic pelagic fish.  Coastal fish  inhabit the relatively shallow and sunlit waters above the continental shelf, while Oceanic fish (which may well also swim inshore) inhabit the vast and deep waters beyond the continental shelf.

5. Pelagic fish range in size from Small coastal forage fis , such as herrings and sardines, to Large apex predator oceanic fishes, such as bluefin tuna and oceanic sharks.  They are usually agile swimmers with streamlined bodies, capable of sustained cruising on long-distance migrations. Many pelagic fish swim in schools weighing hundreds of tonnes. Others are solitary, like the large ocean sunfish weighing over 500 kilograms, which sometimes drift passively with ocean currents, eating jellyfish.

6. Small pelagic fish are usually forage fish that are hunted by larger pelagic fish and other predators. Forage fish filter feed on plankton and are usually less than 10 centimetres long. They often stay together in schools and may migrate large distances between spawning grounds and feeding grounds. They are found particularly in upwelling regions around the northeast Atlantic, off the coast of Japan, and off the west coasts of Africa and the Americas. Forage fish are generally short-lived, and their stocks fluctuate markedly over the years.  SMALL PELAGIC FISHES

7. Medium size pelagic fishes include  Trevally, barracuda, flying fish, bonito, mahi mahi and coastal mackerel. Many of these fish hunt forage fish, but are in turn hunted by yet larger pelagic fish. Nearly all fish are predator fish to some measure, and apart from the top predators, the distinction between predator fish and prey or forage fish is somewhat artificial. Many large pelagic fish are oceanic nomadic species which undertake long offshore migrations. They feed on small pelagic forage fish, as well as medium-sized pelagic fish. At times, they follow their schooling prey, and many species form schools themselves. Examples of larger pelagic fish are  tuna, billfish, king mackerel and sharks and large rays. LARGE PELAGIC FISHES

8. Marine pelagic fish species may be broken down into five subcategories based on the depth of water a species most commonly inhabits. These layers of water, in order of increasing depth, include 1.Epipelagic 2.Mesopelagic 3.Bathypelagic, 4.Abyssopelagic and 5.Hadopelagic zones.

9. SCIENTIFIC CLASSIFICATION KINGDOM- ANIMALIA PHYLUM- CHORDATA CLASS- ACTINOPTERYGII ORDER- SCROMBIFORMES FAMILY- SCROMBIDAE SUBFAMILY- SCROMBINAE TUNA

10. A  tuna  is a saltwater fish that belongs to the tribe  Thunnini , a sub-grouping of the mackerel family (Scombridae). Thunnini comprises fifteen species across five genera, the sizes of which vary greatly, ranging from the  bullet tuna  (max. length: 50 cm (1.6 ft), weight: 1.8 kg (4 lb)) up to the  Atlantic bluefin tuna  (max. length: 4.6 m (15 ft), weight: 684 kg (1,508 lb). The bluefin averages 2 m (6.6 ft), and is believed to live for up to 50 years.

11. Herring  are forage fish, mostly belonging to the family Clupeidae. Herring often move in large schools around fishing banks and near the coast. The most abundant and commercially important species belong to the genus  Clupea , found particularly in shallow, temperate waters of the North Pacific and the North Atlantic Oceans, including the Baltic Sea, as well as off the west coast of South America. Three species of  Clupea  are recognised, and provide about 90% of all herrings captured in fisheries. Most abundant of all is the Atlantic herring, providing over half of all herring capture. Fishes called herring are also found in the Arabian Sea, Indian Ocean, and Bay of Bengal. HERRINGS

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