Gill opening

(Anat.) an opening behind and below the head of most fishes, and some amphibians, by which the water from the gills is discharged. In most fishes there is a single opening on each side, but in the sharks and rays there are five, or more, on each side.

See also: Gill

References in periodicals archive ?
This species has three ontogeny stages before it reaches its adult stage: 1) Ammocoete (subcutaneous eyes, oral opening with folded lips, without marginal papillae, gill area arranged as furrow with seven undeveloped openings, and a brown colored body), 2) Macroftalmia (developed eyes, inner mouth with fleshy lips and supra and infraoral dental lamina, gill openings exposed to the outside and a dark silver dorsal and ventral body coloration), 3) Hypermetamorphic (semicircular mouth opening, with oral and supra-oral odontoid pieces well-developed, eyes relatively small and covered by translucent membrane, gill opening with folds on each edge, developed dorsal fins, a silver body coloration and a bluish pigmentation on the fins) (Ruiz & Marchant, 2004).
1 Insert your hook (copper wire and leader already attached at hook eye) into the gill opening and exit the center of the belly with the hook point while pulling the eye of the hook into the body cavity.
The diameters of gill opening as well as the length of gill arches were measured; the numbers of gill arches and gill rakers were detected.
The count of scales in longitudinal series is made from above the dorsal end of the gill opening to the base of the caudal fin; scales in transverse series are counted from the origin of the anal fin anterodor-sally to the base of the first dorsal fin; gill rakers are counted on the first gill arch, those on the upper limb listed first; rudiments are included in the counts.
The count of scales in longitudinal series is made from above the upper end of the gill opening to the base of the caudal fin; scales in transverse series are counted from the origin of the anal fin obliquely upward to the base of the first dorsal fin; the count of gill rakers is made on the first gill arch, those on the upper limb given first.
inside mouth and gill Opening bright vermilion" ("Description" 43).
Body compressed, head robust; snout blunt, little projecting before eyes (5.7-6.3 in HL), profile almost vertical before eyes, slightly convex from behind eyes to dorsal origin; back slightly elevated; origin of dorsal fin on nape just behind top of gill opening (predorsal length 3.0-3.2 in SL); origin of anal fin slightly behind anus and behind midbody (preanal length 1.8-1.9 in SL).
The specimens of fangjaw eel were identified using the following combination of diagnostic characteristics (Castro-Aguirre and Suarez de los Cobos 1983; Allen and Robertson 1994): body elongated, cylindrical, pointed at both ends; tail longer than head and trunk; pectoral fins present; gill opening relatively elongate, vertical and lateral; snout short, subconical, slightly constricted near tip; teeth very strong and pointed, biserial, largest anteriorly on jaws; body overall tan with abundant small, brown spots on back and sides; and dorsal fin brown.
loki Larson with which it shares a rounded, cup-like, pelvic-fin disc, the same dorsal and anal fin-ray counts, and slender head and body; it differs in having the gill opening extending forward slightly before the posterior margin of the preopercle, longitudinal scale series 34-45, and transverse scale rows 8-10.
I also use small to medium size pilchards, inserting the hook into the gill opening and sliding it into the body just under the skin.
Dorsal rays XIII,17 (last divided to base); anal rays III,18 (last divided to base); pectoral rays 16 (upper two and lowermost unbranched); pelvic rays I,5; transverse scale rows from upper end of gill opening to base of caudal fin 43-45; scale rows above lateral line to origin of dorsal fin 9; scale rows below lateral line to origin of anal fin about 20; lateral line in two sections, the anterior part extending from upper edge of gill cover to below level of posteriormost dorsal fin ray containing 37 scales and the posterior part containing 7 scales along middle of caudal peduncle; transverse scale rows on opercle 7; gill rakers on first branchial arch 5 + 12, total rakers 17, the rakers short and stubby, much shorter than gill filaments; vertebrae 10 + 14.
Gill opening short, 1.0 (0.9) times eye diameter, at 45[degrees] angle, entirely above pectoral-fin base and slightly anterior to it (distance between ventral end of gill opening and base of upper pectoral ray about equal to length of gill opening).