Featured Research

from universities, journals, and other organizations

Measuring The Muscle: New Study By Scripps Researchers Depicts How The Tuna’s Body Is Built For Speed

Date:
April 18, 2001
Source:
Scripps Institution Of Oceanography
Summary:
The mechanics of how fish use their complex muscle systems is a tantalizing puzzle in animal physiology. These muscles are the fundamental sources that fish use to power steady swimming and bursts of speed to elude predators and to capture prey. Scientists have long predicted that tuna, with their highly streamlined body and elevated internal temperatures, are equipped with a "high performance" muscle system. Tuna, researchers suspected, power their swimming by projecting muscle force from the mid-body, where the muscle is concentrated, back to the tail, which essentially acts as a natural, thrust-producing hydrofoil.

The mechanics of how fish use their complex muscle systems is a tantalizing puzzle in animal physiology. These muscles are the fundamental sources that fish use to power steady swimming and bursts of speed to elude predators and to capture prey. Scientists have long predicted that tuna, with their highly streamlined body and elevated internal temperatures, are equipped with a "high performance" muscle system. Tuna, researchers suspected, power their swimming by projecting muscle force from the mid-body, where the muscle is concentrated, back to the tail, which essentially acts as a natural, thrust-producing hydrofoil.

Now, through a study sponsored by the National Science Foundation and conducted at Scripps Institution of Oceanography at the University of California, San Diego, and the National Marine Fisheries Laboratory in Honolulu, researchers have for the first time documented this muscle action in motion. Stephen Katz, Douglas Syme, and Robert Shadwick report their results in the April 12 edition of the journal Nature.

"The anatomy has been known for a long time, especially the idea that the connective tissue architecture in tunas allows muscles to focus their action further down the body," said Shadwick, a professor in Scripps’s Marine Biology Research Division. "We’ve taken measurements directly from swimming fish to show it working this way."

In other fishes, such as trout and mackerel, swimming muscles are distributed more uniformly along the body. When their muscles shorten and produce power, the burst is seen as a wave of contraction that causes the entire body to undulate.

Tuna, however, contain swimming muscles located primarily in the central part of the body. Tendons that angle to the backbone link the muscle with the tail.

Using ultrasound technology, Shadwick and his colleagues attached tiny transducers directly to tuna muscles to record the muscle electrical activity and contraction as tuna swam in a large water tunnel. A device called a sonomicrometer measured the muscle shortening by timing the ultrasound signal between pairs of transducers.

"When we went inside the fish with ultrasound, we saw that the muscle contraction caused bending to occur further down the body," said Shadwick. "We now know that because the muscle tunas use for cruising is close to the backbone–not adjacent to the skin as in other fish–it is allowed to do large amounts of shortening, which means more work and more power production. That’s the essence of how this fish is different from others. Hydrodynamically, that’s a more effective way to swim. If all the middle segments throughout the body were undulating, it would create much more drag. Tunas have a more streamlined body and the motion at the tail acts almost like a propeller."

Shadwick says the results of the study hold implications for research in comparative physiology and the evolutionary biology of fishes. The results also could be important for the design of robotic, self-propelled autonomous underwater vehicles that mimic biological design.

The results have prompted Shadwick to move to other species. With new support from the National Science Foundation, he and Scripps researcher Jeffrey Graham have launched a new study to search for the same results in lamnid sharks.


Story Source:

The above story is based on materials provided by Scripps Institution Of Oceanography. Note: Materials may be edited for content and length.


Cite This Page:

Scripps Institution Of Oceanography. "Measuring The Muscle: New Study By Scripps Researchers Depicts How The Tuna’s Body Is Built For Speed." ScienceDaily. ScienceDaily, 18 April 2001. <www.sciencedaily.com/releases/2001/04/010415222617.htm>.
Scripps Institution Of Oceanography. (2001, April 18). Measuring The Muscle: New Study By Scripps Researchers Depicts How The Tuna’s Body Is Built For Speed. ScienceDaily. Retrieved October 21, 2014 from www.sciencedaily.com/releases/2001/04/010415222617.htm
Scripps Institution Of Oceanography. "Measuring The Muscle: New Study By Scripps Researchers Depicts How The Tuna’s Body Is Built For Speed." ScienceDaily. www.sciencedaily.com/releases/2001/04/010415222617.htm (accessed October 21, 2014).

Share This



More Plants & Animals News

Tuesday, October 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Traditional Farming Methods Gaining Ground in Mali

Traditional Farming Methods Gaining Ground in Mali

AFP (Oct. 20, 2014) He is leading a one man agricultural revolution in Mali - Oumar Diatabe uses traditional farming methods to get the most out of his land and is teaching others across the country how to do the same. Duration: 01:44 Video provided by AFP
Powered by NewsLook.com
Goliath Spider Will Give You Nightmares

Goliath Spider Will Give You Nightmares

Buzz60 (Oct. 20, 2014) An entomologist stumbled upon a South American Goliath Birdeater. With a name like that, you know it's a terrifying creepy crawler. Sean Dowling (@SeanDowlingTV) has the details. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins