Sometimes fishermen will release a sailfish once they've landed it.
The sailfish is the fastest animal in the ocean. There are two species: Istiophorus platypterus, in the Indian and Pacific oceans, and Istiophorus albicans, in the Atlantic ocean. The sailfish has been clocked at over 68 miles per hour over short bursts of speed. Because of its long bill, it's also called the bayonet fish. It is common in warmer waters in medium depths but can dive deeply in pursuit of prey.
Morphology
The sailfish grows to 10 foot 9 inches long and can weigh 182 lbs. It's dark blue above and silver below, and the adults have vertical rows of gold spots on the sides. The snout is modified to form a bill and its jaws have teeth, which distinguishes it from swordfish. When the fin is raised, the middle rays of the dorsal fin are longer than the body is deep. The dorsal fin runs almost the length of the animal's body.
Swimming
The sailfish's long, tapered, compressed body helps it swim quickly, and its long bill causes low resistance flow, which makes for excellent hydrodynamics. Its pelvic fins can be depressed into ventral grooves when it's swimming, and the dorsal fin can be folded on the side to make the body even more tapered. It has lots of white muscle, which is good for acceleration, and the red muscle along the flanks helps the fish sustain its speed. The heat produced by the red muscles is maintained by a network of blood vessels that keeps the fish's blood warmer than the water. The warm blood can be shunted to the fish's brain to help it focus on the hunt.
Food
The Pacific sailfish eats sardines, mackerels and anchovies. They even eat puffer fish and toadfish, which are poisonous to humans. The Atlantic sailfish eats mackerel, tuna, jacks, halfbeaks and needlefish. Sailfish sometimes work cooperatively to catch their prey. The sailfish is not a good eating fish, as the meat is tough, but it is sought after as a game fish. When hooked, it puts up a fight and sometimes takes hours to reel in.
Life Cycle
The Atlantic sailfish spawns in the northern part of the Atlantic ocean, mostly during the summer. The fish spawns near the surface, and a large female can release 4.5 million eggs. The fry are about .125 inches long when they hatch and lack the bill of the adults. When the fry is about a 1/4 inch long, the jaws begin to elongate, and at around 8 inches the fry looks like an adult. In the Pacific, the sailfish spawn in tropical and subtropical regions, again mostly during the summer. Males and females pair up or the males pursue a female. The sailfish is not a long-lived animal. It grows quickly the first two years of life, and then lives only four to five years.
