terms

Anadromous

Refers to fish that migrate up streams from the sea to spawn.

Benthic -

Associated with the bottoms of rivers, lakes, and oceans. Bottom-dwelling.

Cartilage -

A translucent, specialized connective tissue that forms most of the skeleton of embryos, very young vertebrates, and adult cartilaginous fish, such as sharks and rays; in other adult vertebrates much of it is converted into bone

Catadromous - Refers to fish that migrate from freshwater to the ocean to spawn.

Caudal - At or near the tail or the posterior part of an organism's body.

Chordate - An animal with a notochord (a cartilaginous rod that extends the length of the body), dorsal hollow nerve cord (a fluid-filled tube that runs the length of the body), gill slits or pouches, and a tail at some stage in its life cycle.

Clasper - Finger-like projection on the medial side of the pelvic fins of a male shark, ray, and some placoderms; used as an intromittent organ to transfer sperm to female reproductive tract.

Ctenoid Scales - Thin, overlapping dermal scales of some fishes; exposed posterior margins have fine, tooth-like spines.

Cycloid Scales - Thin, overlapping dermal scales of some fish; posterior margins are smooth.

Ectothermy - Capacity to maintain body temperature by gaining heat from the environment, either by conduction or by absorbing radiation.

Ganoid Scales - Thick, bony, rhombic scales of some bony fish; not overlapping.

Gill - In aquatic animals, highly vascularized tissues with large surface area; these are extended out of the body and into the surrounding water for gas exchange.

Ichthyology - Study of fish.

Lateral-Line System - Sensory organ, consisting of canals and grooves on the head and sides of the body of fish and some amphibians, that detects water vibrations.

Operculum - The gill cover in bony fish; also a protective plate in some snails.

Osmoregulation - Maintenance of proper internal salt and water concentrations in the body of a living organism.

Placoid Scale - Type of scale found in cartilaginous fish, with basal plate of dentin embedded in the skin and a backward-pointing spine tipped with enamel.