dorsal fin

Dorsal fin — of an Orca A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals (whales, dolphins, and porpoises), and the (extinct) ichthyosaurs. Depending on the species, an… …   Wikipedia

dorsal fin(s) — the unpaired fin(s) on the midline of the back. Also called the notopterygium. In Pleuronectiformes it is on the opposite side to the anus. In Centriscidae the hind end of the fish has been rotated under the fish so the dorsal fin is on the under …   Dictionary of ichthyology

dorsal fin — An additional fin surface along the top of the fuse lage just in front of the main fin. Dorsal fins help increase directional stability, especially at high air speeds and Mach numbers …   Aviation dictionary

dorsal fin — /ˈdɔsəl fɪn/ (say dawsuhl fin) noun the fin generally developed on the back of aquatic vertebrates …   Australian English dictionary

dorsal fin — noun unpaired median fin on the backs of fishes and some other aquatic vertebrates that help to maintain balance • Hypernyms: ↑fin …   Useful english dictionary

dorsal fin — the fin or finlike integumentary expansion generally developed on the back of aquatic vertebrates. See diag. under fish. [1760 70] * * * …   Universalium

dorsal fin — noun A fin located on the backs of fish and some marine mammals …   Wiktionary

dorsal fin — noun Zoology an unpaired fin on the back of a fish or whale …   English new terms dictionary

dorsal fin —   Kualā …   English-Hawaiian dictionary

dorsal fin ray count — enumeration of the soft dorsal fin rays. In fishes where the smaller rays in front gradually grade into larger rays, these smaller anterior rays are included in the count, e.g. Ictaluridae, Esocidae, Gadidae. Where the first small rays abruptly… …   Dictionary of ichthyology

dorsal fin base length — the distance between the origin and the insertion of the dorsal fin; the length of that portion of the dorsal fin in contact with the body …   Dictionary of ichthyology