anal fin


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anal fin

[′ān·əl ‚fin]
(vertebrate zoology)
An unpaired fin located medially on the posterior ventral part of the fish body.
References in periodicals archive ?
Caudal peduncle length is measured horizontally from the rear of the anal fin to the base of the caudal fin and caudal pedunde depth is the least depth.
Upon reaching hour 845, the anal fin was an average of 0.08 (0.00) wide, with III spines and eight rays.
Therefore, the objective of the current study was to estimate sex-specific age and growth of swordfish by counting growth rings in cross sections of anal fin rays from the southeastern Pacific off Chile.
Dorsal rays VI + I,10; anal rays I,11; pectoral rays 18-20; eye diameter 2.4-2.7 in head length; interorbital width narrow, 6.7-8.15 in head length; first three dorsal spines subequal, the longest 2.4-3.65 in SL, caudal fin rhomboid, 2.6-3.5 in SL; pectoral fins 3.4-3.6 in SL; colour light grey with a midlateral blackish line from behind eye to posterior caudal peduncle; first dorsal spine blackish, a yellow line at base of fin; two rows of yellow spots in second dorsal and caudal fins, and one row in anal fin; a yellow line in middle of caudal fin.
Black markings on fins--except anal fin. Lack of black markings on anal fin differentiates the blacktip from the spinner shark.
Ventral profile convex from lower jaw to end of anal fin base, nearly straight along caudal peduncle.
The results obtained by statistical analysis showed that the wet body weight and anal fin lengths of L.
Dorsal fin flanked basally by 10-12 half-scales, anal fin flanked by 8-10 half-scales, remainder of dorsal and anal fins without scales; 3 large, diamond-shaped scales covering pelvic-fin bases, pelvic fins flanked laterally by 6 half-scales, remainder of pelvic fin and pectoral fin without scales; 7 rows of body scales extending onto base of caudal fin; upper and lower caudal lobes each with a single, enlarged, horizontally elongate scale.
carti reaches or surpasses the vertical through the origin of the anal fin and, in adults, extends posteriorly to the vertical through the origin of the dorsal fin (Lucena 2000).
In total, there were 23 morphological characters chosen that were related to the swimming behaviour and trophic ecology of species: standard length (SL), maximum body height (MBH), body midline height (BMH), maximum body width (MBW), caudal peduncle length (CPdL), caudal peduncle height (CPdH), caudal peduncle width (CPdW), caudal fin height (CH), anal fin length (AL), pectoral fin length (PtL), pelvic fin length (PvL), head length (HdL), head height (HdH), head width (HdW), eye height (EH), mouth height (MH), mouth width (MW), dorsal fin area (DA), caudal fin area (CA), anal fin area (AA), pectoral fin area (PtA), pelvic fin area (PvA) and eye area (EA).
Dorsal rays XI,9; anal rays III,9; pectoral rays 15; lateral-line scales 14-16 + 6-9; median predorsal scales 5; horizontal scale rows on cheek below eye 2; gill rakers 14-17; body depth 2.9-3.2 in SL; head length 2.9-3.2 in SL; snout length 3.8-4.7 in head; caudal fin of male strongly lunate with produced lobes; pelvic fins relatively short, not reaching anal fin origin when depressed; diagnostic live colour pattern features of males include a pink overall coloration with broad, irregular yellow stripe or rectangular blotch on middle of side, and series of 4-5 large, irregular black blotches along back, extending on to adjacent basal portion of dorsal fin; female mainly reddish pink with pupil-sized black spot on upper caudal peduncle.
Partial growth of a gonopodium (modified anal fin used by males in reproduction) is evident in females, thereby indicating some degree of masculinization.