Louisiana Fisheries
Current NewsAbout UsBiological InfoManagement InfoHabitat Info
Louisiana Fisherman Professionalism ProgramAquaculture InfoLegal & Socio-Economic Issues
Fisheries & PeopleResources & PublicationsFisheries FAQsSearch
LSU AgCenter Louisiana Sea Grant Louisiana Fisheries Louisiana Fisheries

Home > Biological Info > Glossary of Terms

Biological Info: Glossary of Terms

Adipose fin
A small fleshy fin on back located between second dorsal and caudal fin. Has no spines or rays.
Anal fin
Single bottom fin between anus and caudal fin.
Bag Limit
The maximum number of crabs that a recreational crabber may have in possession inany one day.
Small, fleshy, worm-like appendage located near the mouth of certain fish. Sensory in nature, may aid in food location.
The harvest of fish or shellfish other than the species for which the fishing gear was used. Examples are blue crabs caught in shrimp trawls or sharks caught on a tuna line. Bycatch is also often called incidental catch. Some bycatch is kept for sale.
Canine teeth
Long, fang-like teeth on either side of mouth (dog-like).
The total number of poundage of fish captured from an area over some period of time. This includes fish that are caught but released or discarded instead of being landed. The catch may take place in an area different from where the fish are landed.
Caudal (tail) fin
The rearmost fin on fish. May be of various shapes, for example: square or flat (snappers), rounded (tripletail), slightly forked (jacks), and deeply forked (tunas).
Caudal peduncle
Rearward portion of the body between caudal fin base and base of the anal fin.
Commercial Fishery
A term referring to the whole process of catching and selling fish and shellfish.
A group of freshwater and saltwater animals having no backbone, with jointed legs and a hard shell made of chitin. Includes shrimp, crabs, lobsters, and crawfish.
An animal that possesses 10 appendages; also a subgroup of the class Crustacea.
Top fin on fish. Usually divided into first (front) and second (back), but may be continuous.
Soft, thread-like continuations of fins. Normally part of most rearward fin ray.


Modified and separated parts of the dorsal and anal fins; normally occur on caudal peduncle.
Fin rays
Soft or bony structures supporting fins. Visible through fin membrane, usually branched on tip.
All the activities involved in catching a species of fish or shellfish.
Gear License
A license, purchased from the state, that permits the owner to use specified types of equipment to catch fish or shellfish. In recreational fishing, for example, gear licenses may be purchased for the use of crab traps, hoop nets, wire nets, trawls, oyster tongs, or crawfish traps, depending on the species sought. The possession of a basic fishing license is required to purchase a gear license.
Gill arch
The larger structure inside the gill cavity. Hard, bone-like structure inside the gill cavity. Hard, bone-like, and semicircular, with finger-like projections (rakers).
Gill cavity
The cavity exposed when gill cover is raised. Contains gills, gill rakers, and gill arches.

Gill rakers

Small, bony structures located inside the gill cavity, attached to the gill arches and projecting forward or upward.
Usually an individual fish or shellfish's increase in length or weight over time. May also refer to the increase in number of fish in a population with time.
The total number or poundage of fish caught and kept from an area over a period of time.
A younf fish or shellfish that has not reached sexual maturity.
The number or poundage of fish unloaded at a dock by commercial fishermen or brought to shore by recreational fishermen for personal use. Landings are reported at the points at which fish are brought to shore.
The newly hatched, earliest stage of growth, which is markedly different in size and form from the adult stage.
Lateral line
Line extending along both sides; contains sensory organs.
The process in which a crustacean sheds its hard outer shell in order to grow.
The part of a fish's or animal's habitat where the young grow up.
Opercle (gill cover)
Bony plate covering gill cavity.
Pectoral fin
Paired fins on sides of the body, chest region.
Living or occurring in the open sea, away from the bottom.
Pelvic fin
Paired fins on sides of the body.
Possession Limit
The number and size of a species that a commercial or recreational fisherman can legally have at any one time.
A species that feeds on other species.
A crab, either a peeler or a buster, that is preparing to molt.
Forward, bony part of the gill cover normally separated by a groove from the rear portion.
Recreational Harvesting
Harvesting fish for personal use, fun, and challenge. Recreational fishing does not include sale of catch.
Hard, bony ridged structures located on either side of the body immediately forward of the tail fin. Usually pointed.
Soft-Shelled Crab
A crab that has shed its hard outer shell, exposing the new soft shell underneath. At this stage, the crab may be cooked and eaten with most of the shell intact.
A group of similar fish or shellfish that can freely interbreed.
Bottom surface (belly) of fish
Vomerine teeth
A patch of small teeth on the roof of the mouth. Rough in texture and visible when mouth is open.
Minute animal life floating in a body of water. Form the primary diet of larval fish and shellfish.


Louisiana Fisheries Louisiana Sea Grant LSU AgCenter