Featured Research

from universities, journals, and other organizations

Satisfied in submerged cages: Salmon happy in deeper water

Date:
February 14, 2011
Source:
The Research Council of Norway
Summary:
It was thought to be impossible to farm salmon in submerged sea cages. But new research demonstrates otherwise. These findings may also prove valuable in combating sea lice and algae.

Conventional sea cages.
Credit: Image courtesy of The Research Council of Norway

The salmon swim bladder requires an air supply in order to regulate the fish's buoyancy. Until now, however, no one realised just how seldom salmon need to surface for air. This need is being quantified by researchers at CREATE, one of 14 Norwegian Centres for Research-based Innovation established four years ago with funding from the Research Council of Norway.

Related Articles


"We kept salmon in completely submerged cages for 17 days," reports Arne Fredheim, Research Manager at CREATE. "The individuals swam somewhat faster than usual but they did not exhibit stress. We also tested the pain threshold for how long salmon can continuously stay below the surface. It took four months for them to become excessively stressed."

The centre's researchers believe that submerged cages can be used for extended periods -- as long as the cages are lifted to the surface at regular intervals to give the fish access to air.

"But more research is needed to adequately determine their threshold limits," asserts Dr Fredheim.

Using submerged cages is advantageous for avoiding storm damage and resisting invasion by algae and sea lice. There is also growing evidence that submersion may increase the effectiveness of sea lice medicines.

CREATE carries out research and develops technology for the sea-cage phase of "fattening up" production fish for the market.

"Our research is part technology and part biology, and interactions are crucial. For instance, we are examining the effects of aquatic temperature, salinity and oxygen content on fish behaviour and welfare. This is fundamental knowledge on which we will base our technology development," explains Dr Fredheim.

In the project "Cage Environment," researchers at CREATE studied hypoxia (oxygen depletion in the aquatic environment) to ascertain critical threshold limits for fish welfare. At the same time, they gained a better understanding of how seawater flows through cage netting. Even though aquaculture sites are placed in sea areas with strong natural currents, there can be too little oxygen in the water at times -- which impedes fish digestion.

"We have developed models for calculating how strong the current must be in relation to cage size and fish density," says Senior Scientist Pål Lader, who works at CREATE. "We have also studied how fish group behaviour affects the current. They often swim in circles en masse, creating a rising spiral current."


Story Source:

The above story is based on materials provided by The Research Council of Norway. Note: Materials may be edited for content and length.


Cite This Page:

The Research Council of Norway. "Satisfied in submerged cages: Salmon happy in deeper water." ScienceDaily. ScienceDaily, 14 February 2011. <www.sciencedaily.com/releases/2011/02/110211074743.htm>.
The Research Council of Norway. (2011, February 14). Satisfied in submerged cages: Salmon happy in deeper water. ScienceDaily. Retrieved November 22, 2014 from www.sciencedaily.com/releases/2011/02/110211074743.htm
The Research Council of Norway. "Satisfied in submerged cages: Salmon happy in deeper water." ScienceDaily. www.sciencedaily.com/releases/2011/02/110211074743.htm (accessed November 22, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, November 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Raw: Baby Okapi Born at Houston Zoo

Raw: Baby Okapi Born at Houston Zoo

AP (Nov. 20, 2014) — The Houston Zoo released video of a male baby okapi. Okapis, also known as the "forest giraffe", are native to the Democratic Republic of the Congo in Central Africa. Video is mute from source. (Nov. 20) Video provided by AP
Powered by NewsLook.com
Your Complicated Job Might Keep Your Brain Young

Your Complicated Job Might Keep Your Brain Young

Newsy (Nov. 20, 2014) — Researchers at the University of Edinburgh found the more complex your job is, the sharper your cognitive skills will likely be as you age. Video provided by Newsy
Powered by NewsLook.com
Mysterious Glow Worms Found in the Amazon

Mysterious Glow Worms Found in the Amazon

Buzz60 (Nov. 20, 2014) — Wildlife photographer Jeff Cremer teamed up with entomologist Aaron Pomerantz and others to investigate a predatory glow worm found in the Amazon. Patrick Jones (@Patrick_E_Jones) explains. 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