Featured Research

from universities, journals, and other organizations

How Hot Tuna (and Some Sharks) Stay Warm

Date:
October 31, 2005
Source:
National Science Foundation
Summary:
Scientists now have direct evidence that the north Pacific salmon shark maintains its red muscle (RM) at 68-86 degrees Fahrenheit (F), much warmer than the 47 F water in which it lives. The elevated muscle temperature presumably helps the salmon shark survive the cold waters of the north Pacific and take advantage of the abundant food supply there. The heat also appears to factor into the fish's impressive swimming ability.

Lamnid sharks maintain an elevated temperature in the red muscle concentrated in their mid-region near the backbone. This specialized anatomy allows the predators to swim fast and continuously, which in turn, allows heat to be retained in the core of the fish leading to local warm-bloodedness. In most other fish, the red muscle is located close to the skin, yielding a fully cold-blooded body and only short bursts of rapid, powerful swimming.
Credit: Zina Deretsky, National Science Foundation

Scientists now have direct evidence that the north Pacific salmon shark maintains its red muscle (RM) at 68-86 degrees Fahrenheit (F), much warmer than the 47 F water in which it lives. The elevated muscle temperature presumably helps the salmon shark survive the cold waters of the north Pacific and take advantage of the abundant food supply there. The heat also appears to factor into the fish's impressive swimming ability.

Related Articles


During what some would say was a better-than-average day at work, Robert Shadwick of the Scripps Institution of Oceanography and his colleagues went salmon shark fishing in the Gulf of Alaska. After catching specimens over 7-feet long and weighing more than 300 pounds, the researchers measured temperatures throughout the sharks' bodies and tested the mechanical power of RM samples.

Their results, published in the Oct. 27 issue of the journal Nature, showed that at 50 F, RM produced only 25-50 percent of the power it produced at 79 F. The researchers concluded that RM temperatures below 68 F could permanently impair muscle function.

National Science Foundation (NSF) program manager, Ione Hunt von Herbing said, "Knowing specific details about the anatomy and physiology of salmon sharks provides key insight into their ability to produce such power and speed during swimming. The knowledge could translate into better designs for underwater vehicles."

The study was funded by NSF's integrative organismal biology program.

Salmon sharks are lamnids, a group of sharks that also includes the mako and great white. Numerous studies have shown that lamnid sharks and tunas share many anatomical and physiological specializations that endow them with their impressive swimming power and speed. In contrast to other fish where the RM is near the skin, the RM of these sharks and tunas is near the backbone. Even though the ancestors of bony tuna and cartilaginous sharks diverged more than 400 million years ago, selection pressure for high-performance swimming in each group seems to have occurred independently about 50 million years ago.

Throughout its life, a salmon shark never stops swimming because it will sink. The body heat generated from continuous swimming elevates the RM temperature, which in turn, warms the surrounding white muscle and allows the shark to survive the frigid waters of the north Pacific. If a shark stops swimming, it could die from cold exposure.


Story Source:

The above story is based on materials provided by National Science Foundation. Note: Materials may be edited for content and length.


Cite This Page:

National Science Foundation. "How Hot Tuna (and Some Sharks) Stay Warm." ScienceDaily. ScienceDaily, 31 October 2005. <www.sciencedaily.com/releases/2005/10/051031133653.htm>.
National Science Foundation. (2005, October 31). How Hot Tuna (and Some Sharks) Stay Warm. ScienceDaily. Retrieved October 30, 2014 from www.sciencedaily.com/releases/2005/10/051031133653.htm
National Science Foundation. "How Hot Tuna (and Some Sharks) Stay Warm." ScienceDaily. www.sciencedaily.com/releases/2005/10/051031133653.htm (accessed October 30, 2014).

Share This



More Plants & Animals News

Thursday, October 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How A Chorus Led Scientists To A New Frog Species

How A Chorus Led Scientists To A New Frog Species

Newsy (Oct. 30, 2014) A frog noticed by a conservationist on New York's Staten Island has been confirmed as a new species after extensive study and genetic testing. Video provided by Newsy
Powered by NewsLook.com
Surfer Accidentally Stands on Shark, Gets Bitten

Surfer Accidentally Stands on Shark, Gets Bitten

AP (Oct. 30, 2014) A 20-year-old competition surfer said on Thursday he accidentally stepped on a shark's head before it bit him off the Australian east coast. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Raw: Dallas Zoo Welcomes Baby Male Giraffe

Raw: Dallas Zoo Welcomes Baby Male Giraffe

AP (Oct. 30, 2014) The Dallas Zoo has a new giraffe with the birth of a healthy male calf. (Oct. 30) Video provided by AP
Powered by NewsLook.com
Endangered Carpathian Ponies Are Making a Comeback in Poland

Endangered Carpathian Ponies Are Making a Comeback in Poland

AFP (Oct. 29, 2014) At the foot of the rugged Carpathian mountains near the Polish-Ukrainian border, ranchers and scientists are trying to protect the Carpathian pony, known as the Hucul in Polish. Duration: 02:17 Video provided by AFP
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