Page 97 - Fish and Amphibians (Britannica Illustrated Science Library)

92 GLOSSARY FISH AND AMPHIBIANS 93

Glossary

when all the organisms belong to one species.
Abyssal Fish Anguilliformes Bony Plates Maximum diversity is reached in stable natural Fishhook Gills
Rare species that inhabit depths of 8,200 feet Fish with a long, slender body without Formations that grow from the skin and have a environments with a maximum variation in the Fishing implement, usually made of steel, Organs that enable fish to breathe. They consist
(2,500 m) and below, where no light reaches. appendages, including eels and morays. protective function for certain species. They substrate and environmental conditions. consisting of a small bar bent in the form of a of filaments connected to the gill arches. The
They have peculiar shapes, with large heads and usually cover the most sensitive parts of the fish, hook and tied to a fishing line. Fishhooks have fish's blood is oxygenated in the gills and
strong teeth for eating other fish, because no Aquaculture especially the head, although they can be found Dorsal Fin different shapes depending on the type of fish circulates to the rest of the body.
vegetation grows at those depths. They attract along the entire body, as in the case of the they are designed to catch. The hook also
prey with lure organs consisting of photophores The raising of aquatic organisms, including fish, Placoderms. Unpaired fin located on the back, which keeps carries bait to attract the prey. Gonophore
that shine in the darkness. shellfish, crustaceans, plants, and seaweed. the fish in a stable position.
These organisms are usually used as food for Cartilaginous Fish Flatfish Anal fin transformed into a reproductive organ.
Actinopterygii humans or animals. Eclosion
Fish with skeletons made of cartilage, such as Fish that have adopted a flat shape and live on Grazers
(Ray-Finned Fish) Barbel the Elasmobranchii, a group that includes sharks The moment when the embryo hatches from the seafloor. They have both eyes on the same
and rays. the egg. Group of fish that nibble on undersea vegetation
Class of fish distinguished mainly by having a Fleshy filament that grows from the lower jaw side of the head, a twisted mouth, and pectoral or coral.
skeleton with bony spines in the fins. They have of certain fish, such as sturgeon, catfish, and cod. Caudal Fin Electric Organs fins on top of the body. The “blind” side of the
a cartilaginous skull and only one pair of gill fish is in contact with the seafloor. Sole is one Habitat
openings covered by an operculum. Unpaired fin at the lower end of the body, Organs of some species, such as electric rays type of flatfish.
Bathypelagic Living space in which a species finds the
forming the tail fin in most fish. and electric eels, specially adapted to discharge
Adipose Fin Fish that live at ocean depths below the electric current. Flying Fish ecological conditions necessary for it to reside
and reproduce.
mesopelagic zone, where light cannot penetrate. Complete Metamorphosis
Small, fleshy lobe located behind the dorsal fin Epipelagic Exocoetids, or flying fish, are a family of 70
in certain groups of bony fish (for example, in Batrachians Phenomenon where the adult form of an animal species of ocean fish in nine genera. They are Harpoon
Salmoniformes). looks nothing like the immature form; examples Relating to organisms that live in open water found in all the oceans, especially in warm
Another name for amphibians. It comes from are frogs and toads. away from the ocean floor, from the surface to subtropical and tropical waters. Their most Iron bar with an arrowhead at one end, often
used to hunt sharks, whales, seabream, brown
Amphibians Batrachia, an old name for the class Amphibia. depths of approximately 660 feet (200 m). notable characteristic is their unusually large meagre, and other species.
This nomenclature is considered out of date. Continental Shelf pectoral fins, which enable them to glide
Animals with a double life. The young live in the Estuary through the air for short distances.
water, and the adults live on land. Many need to Benthic Zone of the seafloor of variable dimensions, Herbivore
stay near water or in damp places to avoid characterized by a slight slope and extending A coastal body of water, partly closed but Fossil Animal that feeds exclusively on plants.
drying out. This is because some species breathe Relating to the environment or habitat from the low tide mark to a depth of open to the ocean, where fresh water and salt
mainly through their skin, which can absorb air consisting of the ocean floor or of the organisms approximately 660 feet (200 m). water mix. Remains or impressions of former living beings
only when damp. (benthos) that live buried in (endobenthic), on that are preserved from past geological ages. Heterocercal
(epibenthic), or near the bottom. Ctenoid Exothermic Type of tail fin in which the spine curves
Ampullae of Lorenzini Fry upward, forming an upper lobe of larger size.
Benthopelagic Type of scale in which the free edge has spines. An organism that cannot regulate or maintain
Organs in sharks for detecting signals emitted its own body temperature is said to be Newly hatched fish whose shape resembles that
by potential prey. Relating to organisms that are found either on Cycloid exothermic. The organism's internal temperature of adults of the same species. Homocercal
the ocean floor or in open water. Usually refers depends on the temperature of its environment. Apparently symmetrical tail fin typical of teleost
Anadromous Fish to fish and crustaceans of deepwater Type of scale in which the free edge is rounded. fish. It is not an extension of the spine.
environments. External Fertilization Ganoid
Fish that reproduce in fresh water and live in Diphycercal Ichthyology
the ocean as adults. Salmon are one example. Bioluminescence Fertilization of eggs that takes place outside the Type of scale made of shiny, enamel-like
Type of tail in which the spinal column extends female's body. The male releases sperm over the material (ganoin) formed in successive layers Branch of zoology concerned with the study of
Anaerobic Property of living beings that can produce light. to the ends of the tail, and the fin is symmetrical eggs after the female deposits them. The eggs over compact bone. The extinct fish fish, including their anatomy, physiology,
Palaeospondylus had this type of scale. The only
above and below. are exposed to the outer environment. behavior, etc.
Breathing process that does not require oxygen. Bony Fish modern fish with ganoid scales are gar, bowfin,
Diversity Filterers and reedfish. Industrial Fishing
Anal Fin Fish with bony skeletons and jaws. Their
skeletons are relatively small but firm. They Degree to which the total number of individual Fish that have evolved to take in water and use Gill Arch Process for catching large quantities of fish
Unpaired fin located in the middle ventral part have flexible fins that allow precise control of organisms in an ecosystem is distributed among filters in their mouth or gills to extract from it from the sea for sale on the international or
of the fish above the anus. their movements. different species. Minimum diversity is reached only the nutrients they need. Bone that anchors the gill filaments or spines. local market.