JUL 23, 2017 1:22 PM PDT

Biological Hydraulic Systems Help Bluefin Tuna Control Their Fins

WRITTEN BY: Anthony Bouchard

The most important tools a fish has for underwater movement are its fins. With these, a fish maintains stability and control despite swimming quickly and fighting currents.

As simple as a fin may seem, Stanford University researchers recently discovered that some fish cheat the system by using more than just bones and muscles to maintain fin rigidity as it moves to combat lateral forces.

Bluefin tuna take advantage of internal biological hydraulic systems to ensure optimal control and stability while swimming at various speeds.

Image Credit: Skeeze/Pixabay

Their study, published in the journal Science, reveals how bluefin tuna utilize a biological hydraulic system. With it, the sickle-shaped median fins on the fish’s body stay rigid even when the creatures are swimming at high rates of speed and fighting ocean currents.

“Animals are exciting sources of elegant engineering solutions in aero- and hydrodynamics. What we have discovered in these tunas is unlike other animal hydraulic systems. It’s a musculo-vascular complex that is integrating the lymphatic system, the skeletal muscles and fin bones,” study lead author Vadim Pavlov said in a statement.

“We’ve shown that in tunas and their fast-swimming relatives this complex functions to generate hydraulic pressure that provides fine adjustment of the shape of their fins. By expanding or retracting their dorsal and anal fins, they alter the physical forces generated by fins, allowing for maneuverability.”

Related: Fish solve problems by 'pooling' experience collectively

For the most part, giant tuna maintain slower rates of speed to conserve energy, but they can easily push 45 miles per hour with the right motivation, such as the presence of food.

When turning on a dime, the additional control and stability produced by these fins are critical. Their muscular systems alone aren’t powerful enough to precisely control the fins when strong lateral forces are acting upon them, so this is where the hydraulic power comes into play.

Given their massive surface area, not only do these hydraulic systems increase their turning accuracy, but they also conserve vital energy while and enable the fish to hunt for prey for longer periods of time.

Researchers made these observations while studying captive giant bluefin tuna at the Monterey Bay Aquarium. There, they watched and took note of the subtle movements as they swam around, something that's harder to achieve in the murky waters of the creature's natural habitat.

Subsequent anatomical examinations revealed fluid-filled cavities just below dorsal and anal median fins. These cavities led to further elaborate channel systems where the fluid could go to control the fins.

The team later generated computer models showing how the fluid moved from one part of the tuna to the other, facilitating fin movement and helping the fish move agilely despite its size.

Perhaps the next step is to figure out how we can learn from these biological hydraulic systems to improve modern robotics used both above and under the ocean’s surface.

“The natural mechanism of hydraulic control of fins could be very attractive in designing of new ‘smart’ control surfaces with changeable shape and stiffness,” Pavlov continued. “This could, for example, enhance the maneuverability of the air and underwater unmanned vehicles.”

Researchers will undoubtedly continue to study the mechanisms that make these tuna fin hydraulic systems possible while simultaneously trying searching to see if any other fish species exhibit similar or varying systems.

It should be interesting to see what we can learn not only from these mechanisms but also to see what other secrets are still lurking below the ocean's surface.

Source: Stanford University

About the Author
  • Fascinated by scientific discoveries and media, Anthony found his way here at LabRoots, where he would be able to dabble in the two. Anthony is a technology junkie that has vast experience in computer systems and automobile mechanics, as opposite as those sound.
You May Also Like
MAR 04, 2020
Genetics & Genomics
MAR 04, 2020
DNA Fragments and Cartilage Recovered From 75-Million-Year-Old Dinosaur Bones
An international team of researchers has analyzed cartilage from a baby duckbilled dinosaur, and they have identified bi ...
MAR 08, 2020
Plants & Animals
MAR 08, 2020
Pumas Struggle to Take Down Guanacos
Pumas, like other large cats, are predacious animals that seek large prey capable of sustaining themselves and their cub ...
APR 21, 2020
Plants & Animals
APR 21, 2020
Male Silverback Gorilla Gets Rejected After Attempt to Impress Female
Silverback gorillas are somewhat renowned for their powerful arms and legs. In many cases, males use their brute strengt ...
MAY 04, 2020
Plants & Animals
MAY 04, 2020
A Capuchin Monkey's Curiosity Can Sometimes Cloud its Judgement
Capuchin monkeys are highly intelligent animals, but they’re also rather curious. They’ve adapted to communi ...
MAY 19, 2020
Earth & The Environment
MAY 19, 2020
Three-fourths of migratory birds in the Pacific threatened by overhunting
Overhunting of migratory shorebirds in the Asia-Pacific region has reached an all-time high - and conservationists are c ...
MAY 24, 2020
Plants & Animals
MAY 24, 2020
The Pistol Shrimp's Secret Weapon...
Pistol shrimp have a unique reputation as one of the ocean’s most intriguing crustaceans. Most are only about the ...
Loading Comments...