Coastal fish

[2] 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.

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.

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 (33 ft) deep.

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.

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.

The inflow of both seawater and freshwater provide high levels of nutrients in both the water column and sediment, making estuaries productive natural habitats.

[9] 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.

Like estuaries, mangrove swamps are important breeding grounds for many fish, with species such as snappers, halfbeaks, and tarpon spawning or maturing among them.

Coral reefs often depend on other habitats in the surrounding area for the supply of nutrients, such as seagrass meadows and mangrove forests.

Within the swarm of females, territorial males perform acrobatic U-swim displays and vigorously defend an area of the reef and its associated harem.

The corallivores are especially territorial, forming mated pairs and staking claim to a specific coral head.

However, most species feed on coral polyps and sea anemones, which can result in problems for the hobby aquarists.

[13][14] Most Pomacentrids are associated with coral reefs in the Indo-West Pacific,[15] with a few species occurring in temperate waters.

[12] The bottom-dwelling species are territorial, occupying and defending a portion of the reef, often centred around an area of shelter.

By keeping away other species of fish, some pomacentrids encourage the growth of thick mats of algae within their territories, leading to the common name farmerfish.

[12] Goatfishes are a family Mullidae of about 55 species of perciform fishes, associated worldwide with tropical reefs.

[12] Goatfish are tireless benthic feeders, possess a pair of long chemosensory barbels ("whiskers") protruding from their chins resembling a goat's beard.

By night the schools disperse and individual goatfish head their separate ways to loot the sands.

They occupy the areas over sandy or rocky bottoms, and can be associated with seagrass meadows and kelp forests.

In the ocean these primary producers are mainly a type of plankton, microscopic phytoplankton which drift in the water column.

Phytoplankton need sunlight for photosynthesis to power carbon fixation, so they are mainly located in sunlit surface waters.

Predatory pelagic fishes found on continental shelves worldwide in both tropical and temperate waters include porgies, barracuda, amberjacks and cutlassfishes.

Stargazers are about 50 species of fishes, belonging to the family Uranoscopidae, and found worldwide in shallow waters.

They bury themselves in sand with only their eyes showing, and leap upwards to ambush fish and invertebrates overhead.

Some species have a worm-shaped lure growing out of the floor of the mouth, which they wiggle to attract prey's attention.

The venom is destroyed when it is cooked, and stargazers are sold in some fish markets with their electric organ removed.