22. Read the text and translate it. Pelagic fish

Pelagic fish live near the surface or in the water column of coastal, ocean and lake waters, but not on the bottom of the sea or the lake. They can be contrasted with demersal fish, which do live on or near the bottom, and reef fish which are associated with coral reefs.

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 percent of known fish species. The oceans have a mean depth of 4000 metres. About 98 percent of the total water volume is below 100 metres, and 75 percent is below 1000 metres.

Marine pelagic fish can be divided into coastal (inshore) fish and oceanic (offshore) fish. Coastal fish inhabit the relatively shallow and sunlit waters above the continental shelf, while oceanic fish inhabit the vast and deep waters beyond the continental shelf.

Pelagic fish range in size from small coastal forage fish, such as herrings and sardines, to large apex predator oceanic fishes, such as the Southern bluefin tuna and oceanic sharks. They are usually agile swimmers with streamlined bodies, capable of sustained cruising on long distance migrations. The Indo-Pacific sailfish, an oceanic pelagic fish, can sprint at over 110 kilometres per hour. Some tuna species cruise across the Pacific Ocean. 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.

Epipelagic fish

Large epipelagic predator fish, like thisAtlantic bluefin tuna, have a deeply forked tail and a smooth body shaped like a spindle tapered at both ends and countershadedwith silvery colours. Small epipelagic forage fish, like Atlantic herring, share the same body features listed for the predator fish above.

Epipelagic fish inhabit the epipelagic zone. The epipelagic zone is the water from the surface of the sea down to 200 metres. It is also referred to as the surface waters or the sunlit zone, and includes the photic zone. The photic zone is defined as the surface waters down to the point where the sunlight has attenuated to 1 percent of the surface value. This depth depends on how turbid the water is, but in clear water can extend to 200 metres, coinciding with the epipelagic zone. The photic zone has sufficient light for phytoplankton tophotosynthese.

The epipelagic zone is vast, and is the home for most pelagic fish. The zone is well lit so visual predators can use their eyesight, is usually well mixed and oxygenated from wave action, and can be a good habitat for algae to grow. However, it is an almost featureless habitat. This lack of habitat diversity results in a lack of species diversity, so the zone supports less than 2 percent of the world's known fish species. Much of the zone lacks nutrients for supporting fish, so epipelagic fish tend to be found in coastal water above the continental shelves. Epipelagic fish can be broadly divided into small forage fish and larger predator fish which feed on them. Forage fish school and filter feed onplankton. Most epipelagic fish have streamlined bodies capable of sustained cruising on migrations. In general, predatory and forage fish share the same morphological features. Predator fish are usually fusiform with large mouths, smooth bodies, and deeply forked tails. Many use vision to predate zooplankton or smaller fish, while others filter feed on plankton. Both predators and their smaller prey are usually countershaded with silvery colours which reduce visibility by scattering incoming light.

shallow waters – мелководье

sunlit waters – залитые солнцем воды

demersal fish – глубоководная рыба