Glossary

adelphophagy: a method of embryonic nutrition where an embryo cannibalises other siblings within the uterus.

adipose eyelid: a transparent outer covering of the eye, either complete or partial, of some bony fish.

adipose fin: a small, fleshy fin without rays or spines between the dorsal and caudal fins of some fishes. Show image.

angular: forming a distinct angle.

anterior: referring to the front portion. Show image.

apex: the tip or peak

asymmetrical: uneven, of different shape or size.

axil: the angular area between the pectoral or pelvic fins and the body.

bar: elongate vertical marking Show image.

barbel: an elongate fleshy tentacle-like sensory projection, usually about the mouth. Show image.

base: the part of a projection (e.g. fin) connected to the body.

benthic: living on the bottom of the ocean.

benthopelagic: inhabiting waters above but near the bottom, or spending part of the time on the bottom and part of the time further up in the pelagic zone.

blotch: an enlarged area or patch that is different in colour from adjacent areas. Show image.

brackish: waters with a salinity between that of freshwater and saltwater.

canine: a slender conical tooth, often enlarged and elongate.

caudal peduncle: the posterior part of body between the rear parts of the dorsal and anal fins, and the caudal fin.

cephalic lobe: a broad lobe on forehead of some rays.

cephalopod: a group of animals including cuttlefishes, nautili, squids and octopi.

cetaceans: a group of aquatic mammals including whales and dolphins.

chondrichthyans: a group of fishes comprising sharks, rays and chimaeras.

circumglobal: distributed around the world within a certain latitude range.

cirri: small, soft, short tendril-like appendages.

claspers: modified portions of pelvic fins in male chondrichthyans used for transferring sperm to female during mating. Show image.

cleithral spine: the spine at the dorsal end of the cleithrum (major bone providing basal support for the pectoral girdle and fin), usually prominent when present and directed backwards.

cloaca: a common opening for digestive, urinary and reproductive tracts. Show image.

common name: the informal name for an animal, which often varies place to place.

compressed: flattened laterally; a body shape much deeper than wide.

concave: curved inwards (opposite of convex).

continental shelf: the shelf-like part of the seabed adjacent to coast to a depth of about 200 m.

continental slope: the typically steep, slope-like part of the seabed bordering the continental shelf to a depth of about 2,000 m.

convex: arched, curved outwards (opposite of concave).

corselet: a band of specialised scales encircling the pectoral region of the body. Show image.

crescentic: shaped like the new moon.

crustaceans: a group of animals including crabs, shrimps, prawns, lobsters and crayfish.

ctenoid scale: a scale with a spiny outer margin.

cusp: a projection on a tooth.

cusplet: a small cusp. Show image.

cycloid scale: a scale with a smooth outer margin, without spines.

demersal: living on or near the bottom of the ocean.

denticle: a small, tooth-like structure; placoid scale of a cartilaginous fish.

depressed: flattened from top to bottom; body shape much wider than deep.

depth: the height of the body or head from top to bottom; also the distance from the sea surface to the bottom.

dermal: relating to the skin.

dermal flaps: outgrowths of skin.

disc: the combined head, trunk and enlarged pectoral fins of those cartilaginous fish with depressed bodies, e.g. stingrays. Show image.

dorsal: the back or upper surface. Show image.

dusky: slightly dark or greyish in colour.

elasmobranch: a group of fishes comprising sharks and rays.

electric organ: organ capable of delivering a mild electric shock.

elongate: extended in length in relation to another object, or drawn out.

emarginate: margin slightly concave; pertains to a caudal-fin shape. Show image.

endemic: native and restricted to a certain area.

epipelagic: the upper part of the oceanic zone from the surface to about 200 m.

estuarine: living mainly in partly enclosed bodies of sea water that are measurably diluted with fresh water (estuaries).

euphausids: small, pelagic, shrimp-like crustaceans.

eye - fork length (EFL): measurement of a length from the eye to the caudal fork (usually for billfish) Show image.

falcate: curved like a sickle.

family: a group term for classifying organisms, containing one or more related genera

filament: A slender, elonage, threadlike structure.

filter feeding: filtering food particles from the water by means of the gill rakers.

finlets: small separate dorsal and anal fins. Show image.

genus: a group term for classifying organisms, containing one or more related species.

gill: an organ used for breathing or extracting oxygen from the water. Show image.

gill arch: a bony angular skeleton that supports the gill filaments and gill rakers. Show image.

gill opening: an opening (usually slit-like in cartilaginous fishes, see 'gill slit') on head that connects the gill chamber to the exterior. Show image.

gill rakers: bony projections along the front edge of the gill arch that help prevent food from escaping through the gill opening. Show image.

gill slit: the opening on head of cartilaginous fishes that connects the gill chamber to the exterior. Show image.

gillnet: a net used to tangle fishes.

habitat: the locality, with its own particular environment, in which an organism lives

hammer-shaped: shaped with paired lateral expansions, like the head of a mallet. Show image.

head: specialised anterior part of an animal on which the mouth and major sensory organs are located; part anterior to fifth gill slit. Show image.

head clasper: small appendage on the forehead of mature male chimaeroid fishes.

histotrophy: a form of embryonic nutrition where the developing embryos receive a lipid-rich histotroph, or uterine milk, usually delivered through extensions of the uterine wall called trophonemata.

hyomandibular pores: line of enlarged pores extending posteriorly from the mouth corners. Show image.

incised: deeply indented.

infraorbital pores: pores in infraorbital canal located along upper jaw below and slightly before eye.

initial phase: colour phase of wrasses and parrotfishes comprising non-juvenile females and immature males (cf. terminal phase).

interdorsal: space on dorsal surface between first and second dorsal fins. Show image.

interdorsal ridge: ridge of skin between dorsal fins. Show image.

internarial space: distance between the nostrils. Show image.

internasal flap: fleshy flap extending between nostrils, sometimes partly covering the mouth. See also internasal curtain. Show image.

interorbital space: area on top of head between eyes. Show image.

jaws: the part of the mouth supporting the teeth.

juvenile: young fish, similar in form to adults but not yet sexually mature.

keel: a fleshy ridge Show image.

labial furrow: shallow groove around the lips. Show image.

lateral: referring to the side, or toward the side

lateral line: a vibration sensory canal along the side of the body with a series of pores that communicate to the outside of the body, often through specialised pored lateral-line scales Show image.

lateral line pores: pores in lateral-line canal, usually beginning behind eye and ending near tail tip.

lateral ridges: fleshy expansions on sides of body. Show image.

lateral-line canal: part of the sensory network of chimaeras; appearing as a distinct line.

lip: the fleshy outer portion of the jaws.

longitudinal: lengthwise (opposite of transverse).

longline: a line bearing numerous baited hooks, typically set horizontally in water column.

lower jaw - fork length: measurement of a length from the most anterior part of the lower jaw to the caudal fork (usually for billfish). Show image.

lunate: crescent shaped; caudal-fin shape that is deeply emarginate with narrow or filamentous lobes. Show image.

margin: edge or rim.

maxillary teeth: upper jaw teeth; the inner row is closest to the inside of mouth, the outer row is closest to the lips.

median: relating to the middle of an object.

mesopelagic: living in open ocean at depths between 200 and 1,000 m.

molar: a low, blunt, rounded tooth for crushing and grinding.

molariform teeth: broad, rounded teeth adapted for grinding.

mouth: the opening through which food enters the alimentary canal. Show image.

multiserial teeth: in multiple rows.

nape: the region of head above and behind the eyes. Show image.

nasal curtain: fleshy flap extending between nostrils, sometimes partly covering the mouth. See also internasal flap. Show image.

nasoral grooves: furrow connecting mouth to the nostrils. Show image.

nektonic: swimming organisms capable of moving against a current and thus not only drifting.

nictitating eyelid: a transparent, moveable membrane or inner eyelid that protects the eye.

nostril: the external opening of the nasal organs. Show image.

oblique: angled or slanting.

obtuse: broadly rounded or having a blunt end.

oceanic: living in the open ocean.

ocellus (plural ocelli): a round eye-like spot or marking with a marginal ring.

ocular: relating to the eye.

oophagy: the method of embryonic nutrition where the embryo feeds on unfertilised eggs entering the uterus.

opercle: the large posterior upper bone of the gill cover.

operculum: the gill cover, composed of the preopercle, opercle, interopercle and subopercle.

oral: relating to the mouth.

orbit: bony cavity in skull where eyeball is housed.

oviparous: producing eggs that hatch after being deposited from the body of a pregnant female.

palatine: paired bones on each side of the roof of the mouth, behind and lateral to the vomer, often bearing teeth.

pelagic: free swimming in the seas, oceans or open water and not associated with the bottom.

plain: uniformly coloured, without a contrasting colour pattern.

plankton: small animals or plants that drift in open water.

polygonal: having many sides (more than four).

population: a biological unit that represents the individuals of a species living in a certain area.

pore: a small secretory or sensory opening.

posterior: referring to the rear portion. Show image.

preanal length: the horizontal distance from the snout tip to the mid-anus. Show image.

precaudal pit: a transverse or longitudinal notch on caudal peduncle just anterior to origin of caudal fin in some sharks. Show image.

preopercle: the upper anterior bone of the gill cover.

preorbital: before the eye. Show image.

purse seine: a fishing net used to encircle surface-dwelling fish and land onto a boat.

quadrangular: shaped with four distinct edges or margins

ray: the supporting element of fins; ray is sometimes used as a collective term to designate both soft rays and spines, but in this resource, it is used to designate exclusively soft rays.

reticulated: divided into a network.

reticulations: markings in the general form of a net.

reticulum: the colour pattern in which lines form a network pattern around and between spots.

retrorse: facing backward.

rhomboidal: diamond-shaped.

rostral teeth: tooth-like projections on the sides of the snout of sawfishes and sawsharks. Show image.

rostrum: a projecting snout. Show image.

rounded: margin evenly convex. Show image.

saddle: a blotch extending across the dorsal surface from one side to another. Show image.

salinity: the concentration of salt in water.

school: a close aggregation of fish swimming in association with each other.

scientific name: the formal binomial name of an organism consisting of the genus and species names; only one valid scientific name per species.

scute: a modified scale that can be enlarged, hardened, ridged, keeled or spiny. Show image.

seine: a fishing net that hangs vertically in the water column and encircles fish when its ends are drawn together.

serrate: with saw-like teeth along a margin. Show image.

snout: the part of the head in front of the eyes. Show image.

soft dorsal fin: the portion of the dorsal fin supported by soft rays. Show image.

soft ray: a fin support element that is composed of two halves (paired laterally), segmented, and usually flexible and branched; rarely, soft rays can be pointed and stiff and look like spines.

species: actually or potentially interbreeding populations that are reproductively isolated from other populations.

spine: a fin support element that is unpaired laterally, unsegmented, unbranched, and usually stiff and pointed; also refers to slender, sharply pointed bony processes not associated with fins. Show image.

spinous dorsal fin: the anterior portion of the dorsal fin that is supported by spines. Show image.

spot: a regularly shaped or rounded area of a colour different from adjacent areas. Show image.

squalene: oil produced from the liver of several sharks.

squalene: oil present in the liver of some sharks.

standard length: length of a fish from snout tip to end of the posterior edge of the hypurals (at caudal-fin base). Show image.

stinging spine: large, serrated bony structure on the tail of some rays. Show image.

stripe: a contrasting longitudinal pattern in the form of a line. Show image.

subequal: almost equal.

submarginal: near the margin of a body part; just inside the outer margin.

subopercle: the lower rear bone in the gill cover.

substrate: the substance forming the bottom of the sea or ocean.

subterminal: positioned near but not at end of an object.

symphysis: relating to the medial junction of either the upper or lower jaw.

tail: part of fish between cloaca and origin of the caudal fin. Show image.

taxonomy: the science of classification of plants and animals.

teeth: hard outgrowths on jaws, used for biting and masticating food. Show image.

teleost: a member of the large group containing most of the bony fishes.

terminal: located at or forming the end of something.

terminal phase: colour phase of adult male wrasses and parrotfishes, usually more brightly coloured than initial phase.

thorn: large denticles on surface of a ray or skate. Show image.

tip: the extremity of a part of a fish. Show image.

total length: longest length of a fish, from snout tip to upper caudal tip or tail tip. Show image.

transverse: directed crosswise, across width (opposite of longitudinal).

trawl: fishing net that is towed behind a boat.

truncate: terminating abruptly in a square end; a caudal-fin shape with a vertically straight terminal border.

trunk: part of fish between head and tail; between fifth gill slit and cloaca.

uniformly: being the same; in terms of colour, it means all the same colour with no variation.

uniserial: teeth in a single row.

ventral: the bottom, lower surface or abdominal part of the body.

viviparous: producing live young from within the body of the parent female.

vomerine teeth: teeth on the vomer bone along the midline of the upper jaw.