Fish launching themselves from the water’s surface is a common and often purposeful behavior. This action is driven by various reasons, ranging from survival instincts to environmental responses.
Defining the Behavior
When fish propel themselves out of the water, this action is commonly described as “breaching,” “leaping,” or “jumping.” While no single, universally exclusive scientific term exists, these terms accurately describe the moment a fish clears the water. This behavior often appears as a sudden, powerful burst, with the fish’s body momentarily airborne before re-entering.
Reasons for Leaping
Fish jump for a range of reasons, many tied to their survival and daily activities. One common motivation is evading predators, where a sudden leap can disorient an attacker, providing a moment for the fish to escape. This quick, evasive maneuver helps them avoid both aquatic and aerial threats.
Another reason for leaping relates to feeding. Some fish species jump to capture prey, such as insects or other small creatures, that are on the water’s surface or hovering just above it. For instance, marbled hatchetfish are known to jump to dislodge insects from overhanging branches, securing an easy meal when the insect falls into the water.
Fish also jump to remove external parasites or irritants from their bodies. The force of re-entry into the water can dislodge these unwanted attachments, providing relief from discomfort. Salmon, for example, may jump to dislodge sea lice they acquire in saltwater.
Migration and spawning behaviors frequently involve leaping. Species like salmon are well-known for their impressive jumps to overcome obstacles such as waterfalls and rapids during their upstream journeys to reach spawning grounds. This demonstrates strength and determination against strong currents.
Environmental stress, particularly low oxygen levels in the water, can prompt fish to jump or surface frequently. While not always a full leap, fish may break the surface in an attempt to access more oxygen. In some cases, fish, such as silver carp, have been observed leaping in large numbers due to low oxygen conditions caused by factors like heavy rainfall and increased water inflow.
Less commonly, jumping may serve as a form of social display or play. Some scientists suggest that, similar to dolphins, fish might jump for enjoyment. This behavior can also be a display of physical prowess, potentially for attracting mates.
Diverse Jumpers and Their Techniques
Many fish species are known for their jumping abilities, each employing specific techniques. Salmon and trout are iconic jumpers, frequently seen clearing waterfalls during their upstream migrations. Their powerful tail thrust and streamlined bodies allow them to launch themselves considerable heights, sometimes over three meters for salmon. These jumps are often precise, with fish aiming for specific currents to aid their ascent.
Various sport fish, including marlin and tarpon, are renowned for their leaps, especially when hooked by anglers. These powerful fish use their speed and strength to propel themselves clear of the water, often shaking their heads violently in an attempt to dislodge a hook. Bass, particularly largemouth bass, are another example of sport fish that become airborne, especially when pursuing baitfish.
Flying Fish
Flying fish, belonging to the family Exocoetidae, represent a unique category of jumpers. They do not truly “fly” by flapping wings like birds, but rather glide through the air using their enlarged pectoral fins. To initiate a glide, they build up speed underwater, then launch themselves from the surface, spreading their “wings” to catch air.
Their specialized tail fin, with a longer lower lobe, can beat rapidly against the water’s surface even after breaking clear, providing additional thrust and extending their glide distance. These glides can cover impressive distances, sometimes over 1,300 feet, reaching speeds of approximately 43 miles per hour. This aerial maneuver is primarily a defense mechanism to escape aquatic predators like tuna and marlin.