![]() ![]() Their baleen plates are narrow and very long - up to 4 m (13 ft) in bowheads - and accommodated inside the enlarged lower lip which fits onto the bowed upper jaw. Right whales are slow swimmers with large heads and mouths. These plates are triangular in section with the largest, inward-facing side bearing fine hairs forming a filtering mat. ![]() A baleen is a row of a large number of keratin plates attached to the upper jaw with a composition similar to those in human hair or fingernails. Baleen whales typically seek out a concentration of zooplankton, swim through it, either open-mouthed or gulping, and filter the prey from the water using their baleens. The suborder contains four families and fourteen species. This distinguishes them from the other suborder of cetaceans, the toothed whales (Odontoceti). The baleen whales (Mysticeti), one of two suborders of the Cetacea (whales, dolphins, and porpoises), are characterized by having baleen plates for filtering food from water, rather than teeth. Most species of barnacles are filter feeders, using their highly modified legs to sift plankton from the water. Porcelain crabs have feeding appendages covered with setae to filter food particles from the flowing water. In lower food concentrations, the feeding basket is pushed through the water for over half a meter in an opened position, and then the algae are combed to the mouth opening with special setae on the inner side of the thoracopods. In the animation at the top of this page, the krill is hovering at a 55° angle on the spot. This is accomplished through filter feeding, using the krill's developed front legs, providing for a very efficient filtering apparatus: the six thoracopods form a very effective "feeding basket" used to collect phytoplankton from the open water. Antarctic krill manages to directly utilize the minute phytoplankton cells, which no other higher animal of krill size can do. Mysids have a high resistance to toxins in polluted areas, and may contribute to high toxin levels in their predators. They are an important food source for herring, cod, flounder, and striped bass. Mysidacea are small crustaceans that live close to shore and hover above the sea floor, constantly collecting particles with their filter basket. This stratagem is also employed by whale sharks. Manta rays can time their arrival at the spawning of large shoals of fish and feed on the free-floating eggs and sperm. Unlike the other large filter feeders, it relies only on the water that is pushed through the gills by swimming the megamouth shark and whale shark can suck or pump water through their gills. Unlike the megamouth and whale sharks, the basking shark does not appear to actively seek its quarry but it does possess large olfactory bulbs that may guide it in the right direction. The basking shark is a passive filter feeder, filtering zooplankton, small fish, and invertebrates from up to 2,000 tons of water per hour. It is believed they may exist to lure plankton or small fish into its mouth. The megamouth shark has luminous organs called photophores around its mouth. Whale sharks have been observed "coughing" and it is presumed that this is a method of clearing a build up of food particles in the gill rakers. Any material caught in the filter between the gill bars is swallowed. This fine sieve-like apparatus, which is a unique modification of the gill rakers, prevents the passage of anything but fluid out through the gills (anything above 2 to 3 mm in diameter is trapped). During the slight delay between closing the mouth and opening the gill flaps, plankton is trapped against the dermal denticles which line its gill plates and pharynx. The whale shark sucks in a mouthful of water, closes its mouth and expels the water through its gills. ![]() In addition to these bony fish, four types of cartilaginous fishes are also filter feeders. They are also a natural check to the deadly red tide. Adult menhaden can filter up to four gallons of water a minute and play an important role in clarifying ocean water. For example, the Atlantic menhaden, a type of herring, lives on plankton caught in midwater. ![]()
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