Sturgeon, ancient fish known for their bony plates and elongated bodies, are known for leaping entirely out of the water. This striking behavior is a well-documented part of their natural history, often surprising observers in freshwater and estuarine habitats. A large sturgeon clearing the water surface is a powerful spectacle, highlighting the unique adaptations of this prehistoric fish.
Reasons Behind the Leap
A primary explanation for sturgeon leaps relates to swim bladder regulation. Sturgeon are physostomous fish; their swim bladder connects to their gut, allowing them to gulp air from the surface to adjust buoyancy. This air gulping helps them maintain neutral buoyancy, useful as they move between depths or when their swim bladder loses gas. This mechanism helps conserve energy while hovering or resting.
Another theory suggests sturgeon jumping serves as communication within groups. When a sturgeon leaps and crashes back into the water, it creates a loud splash and distinct underwater sounds, like “snaps” or “clicks.” These acoustic signals help maintain group cohesion, especially in “holding areas” where many sturgeon gather. This behavior allows individual fish to signal their presence and location.
An older, less supported hypothesis proposed sturgeon jump to dislodge parasites. Researchers now consider this unlikely due to parasite attachment. Other less common reasons include escaping predators, courtship displays, or aiding egg shedding during spawning. This jumping activity does not appear related to feeding.
The Mechanics and Frequency of Sturgeon Jumps
Sturgeon jumps display power, with fish propelling themselves several feet into the air. Gulf sturgeon can leap over 7 feet, and white sturgeon up to 10 feet. The ascent is often nearly vertical, driven by strong tail beats, and fish may twist their bodies before re-entering the water.
The re-entry is accompanied by a distinctive and loud sound, often referred to as a “sturgeon thunder” or a “loud smack.” This percussive sound can be heard from a considerable distance, sometimes up to half a mile away on the surface and even further underwater. The frequency of these jumps varies, but they are a common occurrence, particularly in designated “holding areas” where sturgeon gather. During peak times, especially in mid-summer, jumps can occur with notable frequency, sometimes several times per minute in concentrated areas. This activity is often observed more intensely during dawn and dusk.
Safety and Human Interaction
The impressive size and leaping behavior of sturgeon present a potential, albeit rare, risk to human recreational activities on the water. Adult sturgeon can measure up to 8 feet in length and weigh over 200 pounds. An unexpected collision with a fish of this size can cause serious injury or damage to vessels, including boats and kayaks.
Numerous incidents have been reported where jumping sturgeon have struck boaters, leading to injuries and, in tragic cases, fatalities. While sturgeon are not aggressive and these encounters are accidental, the sheer force of impact can be substantial, especially at higher boating speeds. To minimize risks, individuals recreating in sturgeon habitats should maintain heightened awareness of their surroundings. Boaters are advised to operate their vessels at slower speeds, wear life jackets, and avoid standing or sitting on the bow of the boat. Reducing speed provides more time to react to a sudden jump and lessens the potential impact force if a collision occurs.