Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves.Australian blennyRock gobyLong-spined sea scorpionSmooth lumpsucker inflated in a defensive response.SeahorseFlatfishCleaner wrasses working on a dragon wrasseCommon triplefinGrey mulletGarfishSchooling anchoviesEuropean spratAtlantic herringUnderwater video loop of a school of herrings migrating to their spawning grounds in the Baltic SeaThe jolthead porgy is a porgi gruntGreat barracuda and jacksThe yellowtail amberjack, pound for pound, is one of the hardest fighting fish in the ocean.The largehead hairtail is a cutlassfishThe polar cod is found further north than any other fish species. It frequents river mouths and feeds on plankton and krill. It is preyed on by narwhals, belugas, ringed seals and seabirds.The John dory is so thin it can hardly be seen from the front. The large eyespot on the side of its body confuses its prey.The turbot is a large left-eyed flatfish usually found not too far from shore in sandy shallow waters. It is a prized food fish.The red gurnard is a mail-cheeked fish found to depths of around 180 metres. They often grunt when captured as air is expelled from its air bladder.A speckled sand perch perched on coral sandThe rudderfish (Centrolophus niger) is a medusa fishMalabar grouperAtlantic wreckfish inhabit caves and wrecks. They are good game fish, reaching a maximum reported length of 210 cm (6.9 ft) and weight of 100 kg (220 lb). Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves. Coastal fish are the most abundant in the world. They can be found in tidal pools, fjords and estuaries, near sandy shores and rocky coastlines, around coral reefs and on or above the continental shelf. Coastal fish include forage fish and the predator fish that feed on them. Forage fish thrive in inshore waters where high productivity results from upwelling and shoreline run off of nutrients. Some are partial residents that spawn in streams, estuaries and bays, but most complete their life cycles in the zone. Coastal fish are found in the waters above the continental shelves that extend from the continental shorelines, and around the coral reefs that surround volcanic islands. The total world shoreline extends for 356,000 km (221,000 mi) and the continental shelves occupy a total area of 24.286 million km2 (9 376 million sq mi). This is about 4.8% of the world's total area of 510.072 million km2. Nearshore fish, sometimes called littoral fish, live close to the shore. They are associated with the intertidal zone, or with estuaries, lagoons, coral reefs, kelp forests, seagrass meadows, or rocky or sandy bottoms, usually in shallow waters less than about 10 m deep. Intertidal fish are fish that move in and out with the tide in the intertidal zone of the seashore, or are found in rock pools or under rocks. The intertidal zone of rocky shores can contain indentations which trap pools of salty water, called rock pools. Living in these habitats are communities of hardy plant and animal species specially adapted for coping with the volatile environment around them. The plants and animals interact with each other and with the rock pool to form miniature ecosystems, easily accessible to students and a source of fascination for young children. Plants such as seaweeds, cnidarians such as sea anemones, arthropods like barnacles, and molluscs such as the common limpet and the common periwinkle can be permanent residents of rock pools. But most rock pool animals, such as crabs, shrimp and fish are just temporary residents, occupying a rock pool only until the next tide takes them to a new location. Some rock pool fish which are temporary residents include the long-spined sea scorpion, the pipefish worm, the rock goby and the common lumpsucker. However some other rock pool fish are territorial in nature, and will stay with the same pool for extended periods. Examples are the common blenny and its near relative the butterfish. Estuaries are partly enclosed coastal bodies of water with one or more rivers or streams flowing into them, and with a free connection to the open sea. These brackish water habitats form a transition zone between river environments and ocean environments, and ecological successions can form along the way. Estuaries are subject to both marine influences, such as tides, waves, and the influx of saline water; and riverine influences, such as flows of fresh water and sediment. The inflow of both seawater and freshwater provide high levels of nutrients in both the water column and sediment, making estuaries productive natural habitats. Fishes that spend time in estuaries (or river mouths) need to be euryhaline (tolerant to a range of salinities). Estuaries provide an unstable environment for fish, where the salinity changes and the waters are often muddy and turbulent. In warmer climates, estuaries have mangroves around their edges. At times there may be only a few different fish species present in an estuary, but seasonal migrants, including eels, salmonids, and some forage fish such as herrings and sprats increase the diversity in the estuary.