14 imagesBlue marlin, Makaira nigricans, is common to 12 ft (3.4 m) and known to exceed 2000 lb (900 kg). Males, however, grow much more slowly than females and do not generally exceed 300 lb (136 kg), and the species' average weight is closer to 400 lb (180 kg); all trophy fish are females. The fish's body is cobalt blue on top, with a silvery white belly, and the upper jaw is famously elongated like a spear. The tail is high and crescent-shaped. The dorsal fin is pointed at the front end, and the body is covered in embedded scales which end in one or two sharp points. The lateral line is reticulated, or interwoven like a net, but this characteristic is difficult to see in large specimens. A highly migratory species, the Blue marlin is usually found offshore in deep blue tropical or temperate waters. It is known to make regular seasonal migrations, moving toward the equator in winter and away again in summer. Some scientists recognize Makaira mazara and Makaira nigricans as two different species based on differences in the lateral line. Many, however, lump the two together as a single species occurring in the Atlantic, Pacific and Indian Oceans.