Glossary
Fish terminology
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Ectothermic |
Of or relating to
an organism that regulates its body temperature largely by
exchanging heat with its surroundings; cold-blooded. |
| Poikilothermic |
An organism, such as a fish or
reptile, having a body temperature that varies with the
temperature of its surroundings; an ectotherm. |
| Placoid |
Placoid scales are found on cartilaginous
fish including sharks. These scales, also called denticles, are
similar in structure to teeth. |
| Cosmoid
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True cosmoid scales can only be found on the
extinct Crossopterygians. The inner layer of the scale is made
of lamellar bone. On top of this lies a layer of spongy or
vascular bone and then a layer of dentine like material called
cosmine. The upper surface is keratin. The coelacanth has
modified cosmoid scales that lack cosmine and are thinner than
true cosmoid scales. |
| Ctenoid
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Ctenoid scales have a toothed outer edge,
and are usually found on more derived fishes with spiny fin
rays, such as bass and crappie. |
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Cycloid |
Cycloid scales have a
smooth outer edge, and are most common on more primitive fish
with soft fin rays, such as salmon and carp. |
| Aquaculture |
the cultivation of aquatic animals and
plants, esp. fish, shellfish, and seaweed, in natural or
controlled marine or freshwater environments; underwater
agriculture. |
| Agnatha |
the class of vertebrates comprising the
lampreys, hagfishes, and several extinct forms, having no jaws
or paired appendages. |
| Anadromous |
Migrating up rivers from the sea to breed in
fresh water. Used of fish. |
| Protrusible |
capable of being thrust forward, as the
tongue |
| Chordate |
Any of numerous animals belonging to
the phylum Chordata, having at some stage of development a
dorsal nerve cord, a notochord, and gill slits and including all
vertebrates and certain marine animals, such as the lancelets. |
| Fusiform |
spindle-shaped; rounded and tapering from
the middle toward each end, as some roots. |
| Filiform |
Having the form of or resembling a
thread or filament. |
| Vermiform |
resembling a worm in shape; long and
slender. |
| Hypural |
Under the tail; -- applied to the
bones which support the caudal fin rays in most fishes. |
| Photophore |
a luminous organ found in certain fishes and
crustaceans. |
| Scorpeaniforms |
is an order of ray-finned fish, but it has
also been called the Scleroparei. Species in this
order have recently been reclassified into the Perciformes. |
| Chondrichthyes |
cartilaginous fishes |
| Osteichthyes |
a class of fish having a skeleton composed of bone in addition
to cartilage |
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