Search results
Results from the WOW.Com Content Network
The shape of the caudal fin reflects the shark's lifestyle, and can be broadly divided into five categories: Fast-swimming sharks of open waters, such as the mackerel sharks, have crescent-shaped tails with upper and lower lobes of almost equal size. The high aspect ratio of the tail serves to enhance swimming power and efficiency.
The shape, size, position and colour of the dorsal fin varies with the type of billfish, and can be a simple way to identify a billfish species. For example, the white marlin has a dorsal fin with a curved front edge and is covered with black spots. [4] The huge dorsal fin, or sail, of the sailfish is kept retracted most of the time. Sailfish ...
The adipose fin is a soft, fleshy fin found on the back behind the dorsal fin and just forward of the caudal fin. It is absent in many fish families, but found in nine of the 31 euteleostean orders ( Percopsiformes , Myctophiformes , Aulopiformes , Stomiiformes , Salmoniformes , Osmeriformes , Characiformes , Siluriformes and Argentiniformes ...
Mackerel sharks, also called white sharks, are large, fast-swimming sharks, found in oceans worldwide. They include the great white, the mako, porbeagle shark, and salmon shark. Mackerel sharks have pointed snouts, spindle-shaped bodies, and gigantic gill openings. The first dorsal fin is large, high, stiff and angular or somewhat rounded.
The pelvic and the anal fins are large, broad, and rounded, and are positioned to the tail-end of the frilled shark's body. The very long caudal fin is a triangular tail that has neither a lower lobe nor a ventral notch in the upper lobe, and has a margin equipped with sharp, chisel-shaped dermal denticles, which the shark can enlarge. [4]
Due to their primitive anatomy, hexanchiforms were previously considered the most basal group of sharks. However, more recent phylogenetic studies indicate that while primitive, they in fact belong to the superorder Squalomorphii, which also contains dogfishes, angelsharks, and sawsharks, although they are thought to be the most basal member of the group.
Shark fin soup is a status symbol in Asian countries and is erroneously considered healthy and full of nutrients. Scientific research has revealed, however, that high concentrations of BMAA are present in shark fins. [139] Because BMAA is a neurotoxin, consumption of shark fin soup and cartilage pills, therefore, may pose a health risk. [140]
The claspers of a spotted wobbegong shark (Orectolobus maculatus) The claspers of a young spinner shark (Carcharhinus brevipinna) In biology, a clasper is a male anatomical structure found in some groups of animals, used in mating. A close up view of a chimaera clasper (Hydrolagus collie). Note the many small tooth-like projections covering the ...