Various marine animals are capable of aerial locomotion, i.e., jumping out of the water and moving through air. Some possible reasons for this behavior are hunting, escaping from predators, and saving energy for swimming or breathing. Some of the jumping behaviors initiate gliding and taxiing in air, while some of them end up falling back to water.

Penetrating water surface The speed of motion in air is faster than in water because of drag. The drag force is proportional to density of the fluid. Its direction is oppositional that of the marine animal leaving the water will feel almost no drag, since air density is 1,000 times less than water density. Usually, animals gain thrust for the jumping as they travel underwater. Some of these maneuvers are group behavior and appear synchronized to an observer.

Mechanism Porpoising

Porpoising is high-speed swimming close to water surface with many leaving and re-entering the water nose-first, seen with cetacean surfacing behaviour and breaching behaviors seen in penguins, pinnipeds and many fish in the wild. Dolphins and porpoises purposefully use porpoising to save energy when swimming high-speed.Au, D., and D. Weihs. 1980. "At High Speeds Dolphins Save Energy by Leaping." Nature 284 (5756): 548–50. doi:10.1038/284548a0Weihs, D. 2002. "Dynamics of Dolphin Porpoising Revisited" Integrative and Comparative Biology 42 (5): 1071-1078 Penguin porpoises in group for long-distance traveling,Yoda, K., K. Sato, Y. Niizuma, M. Kurita, C. Bost, Y. Le Maho, and Y. Naito. 1999. "Precise Monitoring of Porpoising Behaviour of Adelie Penguins Determined Using Acceleration Data Loggers." Journal of Experimental Biology 202 (22): 3121–26. and seals porpoise as group playWilson, Susan. 1974. "Juvenile Play of the Common Seal Phoca vitulina vitulina with Comparative Notes on the Grey Seal Halichoerus grypus" Behaviour 48 (1/2): 37-60

Tail beating

The fish approach the water surface at high speed (about 10 m/s in large fish; 20-30 body lengths/s) with their lateral fins furled against the body. They get accelerated by beating their tails rapidly, and break through the water surface at a shallow angle to the horizontal. Ray-finned fish in the orders Beloniformes and Salmoniformes have this jumping behavior. The ray-finned fish includes needlefish,Lauritzen, D. V., F. Hertel, and M. S. Gordon. 2005. "A Kinematic Examination of Wild Sockeye Salmon Jumping up Natural Waterfalls." Journal of Fish Biology 67 (4): 1010–20. doi:10.1111/j.0022-1112.2005.00799.x flyingfish,Davenport, John. 1994. "How and Why Do Flying Fish Fly?" Reviews in Fish Biology and Fisheries 4 (2): 184–214. doi:10.1007/BF00044128 halfbeak, and sauries. Salmon and trout jump when in fresh water to prey on low-flying insects or to overcome weirs, rapids and small waterfalls during anadromous migrations upstreams for spawning.

C-start

C-start is escape reflex employed by most of the fish that jump out of water. The fish curves its slender body into a shape of letter "C" before the vigorously straightening the tail like a spring, which propels the fish with enough force to breach the water surface.Weihs, D. 1972. "A Hydrodynamical Analysis of Fish Turning Manoeuvres" Proceedings of the Royal Society of London. Series B, Biological Sciences 182 (1066): 59-72 Freshwater butterflyfish jumps out of water by curving its body.Saidel, William M., Gabriel F. Strain, and Shannon K. Fornari. 2004. "Characterization of the Aerial Escape Response of the African Butterfly Fish, Pantodon Buchholzi Peters." Environmental Biology of Fishes 71 (1): 63–72. doi:10.1023/B:EBFI.0000043153.38418.cd The fish is known for its enlarged pectoral fins but it falls back to water instead of gliding. Freshwater hatchetfish exhibits a ballistic aerial path.

Jet propulsion Jet propulsion generates thrust and momentum by shooting out water jets. Flying squid is known for their behavior of leaping out of the water. Ommastrephinae and Todarodinae are two subfamilies of squids under the family of Ommastrephidae. They utilize jet propulsion to jump out of water as they do underwater, including Japanese flying squid..,Muramatsu, K., J. Yamamoto, T. Abe, K. Sekiguchi, N. Hoshi, and Y. Sakurai. 2013. "Oceanic Squid Do Fly." Marine Biology 160 (5): 1171–75. doi:10.1007/s00227-013-2169-9 Humboldt squid,O’Dor, Ron, Julia Stewart, William Gilly, John Payne, Teresa Cerveira Borges, and Tierney Thys. 2013. "Squid Rocket Science: How Squid Launch into Air." Deep-Sea Research Part II: Topical Studies in Oceanography 95: 113–18. doi:10.1016/j.dsr2.2012.07.002 Neon flying squid, sevenstar flying squid, and Wellington flying squid. Squid flight may be thought to reduce the cost of migration. The acceleration of Sthenoteuthis pteropus in air is 265 body lengths/s2 (24.5 m/s2), which is found to exceed that in water (79 body lengths/s2).

Other

The mechanisms and jumping patterns of some aquatic animals are not clear. Mobula penetrates sea surface by many photo evidences.Albert, Paul. 2007. "The flying mobulas of the Sea of Cortez" Underwater Naturalist Great white shark attacks seals near water surface at Seal Island in South AfricaMartin, R. Aidan, Neil Hammerschlag, Ralph S. Collier, and Chris Fallows. 2005. "Predatory Behaviour of White Sharks (Carcharodon Carcharias) at Seal Island, South Africa." Journal of the Marine Biological Association of the United Kingdom 85 (05): 1121–35. doi:10.1017/S002531540501218X

See also Tradeoffs for locomotion in air and water Flying and gliding animals

References

External links The Flying Mobulas of the Sea of Cortez