Do Sharks Really Have to Keep Swimming to Breath?

Do sharks really have to keep swimming to breath?

Check out this answer from Consensus:

The necessity for sharks to keep swimming to breathe is more complex than previously thought. While ram ventilation is a common strategy among many species, sharks exhibit a range of behaviors and physiological adaptations that allow them to regulate their respiratory needs. These adaptations include changes in swimming speed, gape size, and metabolic rates, which are influenced by factors such as body size, temperature, and environmental conditions. The research suggests that while continuous swimming is important for some species, others have evolved different strategies to meet their respiratory demands.

Sharks have long been thought to need constant movement to ensure water flows over their gills for respiration. This belief stems from the observation that many species exhibit a behavior known as ram ventilation. However, recent studies have provided a more nuanced understanding of shark respiratory physiology and behavior.

Ram Ventilation and Swimming Speed of Sharks

Ram ventilation is a process where sharks swim with their mouths open, allowing water to pass over their gills, facilitating oxygen uptake. Research on the bonnethead shark, Sphyrna tiburo, has shown that these sharks adjust their swimming speed and mouth gape in response to changes in dissolved oxygen levels, suggesting that swimming speed and gape are important for respiratory regulation in ram ventilating sharks1.

Physiological Responses to Swimming in Sharks

In the leopard shark, Triakis semifasciata, swimming has been observed to cause significant changes in vascular pressures and blood respiratory properties. These changes enable the shark to sustain aerobic swimming by increasing cardiac output and utilizing its venous oxygen reserve2. Additionally, metabolic rate, heart rate, and tailbeat frequency have been recorded in leopard sharks to evaluate the relationship between these factors during steady swimming. A significant linear relationship was found between tailbeat frequency and swimming speed, indicating that these physiological parameters are closely linked to swimming behavior3.

Metabolic Rates and Swim Speeds on Sharks

Studies on juvenile lemon sharks, Negaprion brevirostris, using acceleration biologgers, have provided insights into the relationship between swimming speeds and metabolic rates. These studies have shown that acceleration-derived tailbeat frequency is a strong predictor of metabolic rate, and that sharks exhibit different swimming velocities influenced by environmental factors such as tide state and diel period4. Similarly, juvenile white sharks, Carcharodon carcharias, have been found to modulate their activity rates in response to environmental temperature profiles, likely as a strategy to optimize bioenergetic efficiency5.

The Influence of Body Size and Temperature in Sharks

The scaling of swim speed in sharks has been linked to metabolism, with a geometric model predicting a positive scaling relationship between swim speeds and body size, taking into account the scaling of gill dimensions6. Furthermore, the nurse shark, Ginglymostoma cirratum, has been shown to have the lowest metabolic rates reported for any shark species, with metabolic rates and swimming dynamics influenced by temperature7.

Do sharks really have to keep swimming to breath?

Madi Green has answered Likely

An expert from University of Tasmania in Marine Biology, Genetics

Sharks require water to travel over their gills in order for them to ‘collect’ oxygen and breath. Some species of sharks need to keep swimming to ensure this happens while others can lay on the bottom and fan or siphon water over their gills without moving.

Do sharks really have to keep swimming to breath?

Chantelle Penney has answered Likely

An expert from Trent University in Biology, Ecophysiology, Marine Biology

Most fish have an operculum which is a flap covering the fish’s gills. The purpose of this flap is to help direct/push water over the gills so that the fish can pick up oxygen from the water (when you watch a fish you can see the operculum moving in and out as it ventilates). Sharks lack an operculum and only have gill slits, so it uses a method called ‘ram ventilation’; the shark will swim with its mouth open so that water enters the mouth, flows over the gills, and exits the gill slits. However, sharks don’t necessarily always have to swim for this to occur. Sometimes they will hang out in currents, facing into the direction of the water flow to achieve ventilation via the same principle.

Do sharks really have to keep swimming to breath?

Douglas Fenner has answered Uncertain

An expert from National Oceanic and Atmospheric Administration in Marine Biology

Pelagic sharks have to swim continuously to keep from sinking into very deep water, sharks do not have a gas-filled swim bladder. But reef sharks and other shallow-water sharks can rest on the bottom and breathe fine, they frequently do that. And at times they swim continuously I’ve seen both myself many times.