dorsal fin

(redirected from Dorsal fins)
Also found in: Dictionary, Thesaurus, Encyclopedia.

dorsal fin

n.
One of one or more unpaired fins on the back of fishes and certain marine mammals.

dorsal fin

any unpaired median fin on the backs of fishes and some other aquatic vertebrates. The fin maintains balance during locomotion.
References in periodicals archive ?
Origin of first dorsal fin slightly posterior to pelvic-fin base, the predorsal length 3.
The pterygiophores of the spinous rays of the dorsal fin develop from posterior to anterior and begin to form during notochord flexion.
12 it was evident when first collected; head with broad blackish stripe from snout to upper rear margin of operculum, interrupted by eye; silvery spot on upper operculum immediately below aforementioned dark stripe, remainder of operculum and cheek yellowish to bronze; dorsal fins reddish with pronounced dark brown to blackish submarginal stripe and broad, white outer margin; anal fin bluish grey to yellow or reddish; caudal fin dusky grey with narrow, white posterior margin; pelvic fins dusky grey to whitish; pectoral fins translucent.
posterior end of extrascapular not exceeding postemporal spine); by having the posterior end of the first proximal pteryigiophores of dorsal fin of the same size as the anterior edge (vs.
The salient colour differences are the orange and blue spots and orange-tipped rays of the dorsal fins of neumanni (no obvious spots on these fins in masuii, the first dorsal edged in dark reddish brown, and the second dorsal rays tipped in dark reddish brown), the dark brown band behind the middle of the eye of neumanni, and the four different coloured bands on the base of the anal fin of neumanni (only a single orange line in masuii).
Characteristics useful for separating larval and juvenile finescale menhaden from gulf menhaden included 1) the presence or absence of pigment at the base of the insertion of the pelvic fins; 2) the standard length at which medial predorsal pigment occurs; 3) differences in the number of dorsal fin ray elements; and, 4) the number of vertebrae.
8 mm SL) are generally dusky grey with spotting evident only on the dorsal fins.
In addition, samples of body muscle from the head, mid, and tail regions were compared with samples of muscle from the base of pectoral and dorsal fins taken from the same specimens of M.
7): translucent pale blue dorsally on head and body (vertebral column visible as a dark brown band), crossed by 10 yellowish brown bars; side of body yellowish brown; all of head and body densely speckled with dark brown, most heavily and more darkly speckled over abdomen; dorsal fins with yellowish brown rays and transparent membranes dotted with brownish yellow, the outer margin broadly brownish yellow; anal and caudal fins translucent yellow with brown rays stippled in dark brown; iris densely stippled with black except dorsally where golden, speckled with dark brown; a very narrow yellow ring around pupil.
8 Counts Dorsal fin 23 23-24 20-21 Caudal fin 22 20-22 19-21 Anal fin 24 22-24 21-22 Pelvic fin 5 5 5 Pectoral fin 11 10-11 8-9 Scales in longitudinal series 28 29 Scales in transversal series 12 9 Horizontal scales around caudal 10 16 peduncle
A roosterfish raced behind the boat, attacking the bait and flaring its trademark dorsal fins that resemble a big comb.