Featured Research

from universities, journals, and other organizations

Aging In Salmon Depends On Choosy Bears

Date:
December 13, 2007
Source:
Public Library of Science
Summary:
According to George Bernard Shaw: "We don't stop playing because we grow old; we grow old because we stop playing." But how fast does that aging occur once started? In the case of populations of salmon in Alaska studied by Stephanie Carlson and colleagues at the University of Washington and McGill University and reported on in this week's PLoS ONE, it all depends on how choosy are the bears which feed on them.

According to George Bernard Shaw: "We don't stop playing because we grow old; we grow old because we stop playing." But how fast does that aging occur once started? In the case of populations of salmon in Alaska studied by Stephanie Carlson and colleagues at the University of Washington and McGill University and reported on in this week's PLoS ONE, it all depends on how choosy are the bears which feed on them.

Pacific salmon are noted for not feeding during their breeding period, relying instead on stored energy reserves and for their rapid senescence -- the physiological deterioration associated with aging -- once breeding is over. It is, thus, more beneficial for bears to consume fish with fewer signs of senescence because these fish have more energy reserves. However, these "fresh" fish are also more vigorous and harder to catch and so are more effectively caught in smaller, shallower streams.

Carlson and colleagues studied populations of salmon and brown bears in six creeks in southwest Alaska to determine whether the rate of senescence in salmon was driven primarily by the rate of predation by bears or by the tendency of the bears to prey on salmon with less evidence of senescence. They measured the reproductive lifespan of each fish as the number of days between stream entry and death and recorded the mode of death for each fish. They found that the selectivity of the bears for salmon of various senescent conditions was the prime factor determining the rate of senescence in the salmon.

In populations where bears killed old, decrepit salmon, the salmon senesced more slowly relative to populations where bears killed young, "fresh" salmon. This result contrasts with the established expectation that senescence evolves because of the number of individuals killed by predators, rather than their physical characteristics.

"The work offers new insight into the relationship between an individual's senescent condition and it's susceptibility to predation and the long-term consequences of this relationship" says Carlson, corresponding author on the publication.

Citation: Carlson SM, Hilborn R, Hendry AP, Quinn TP (2007) Predation by Bears Drives Senescence in Natural Populations of Salmon. PLoS ONE 2(12): e1286. doi:10.1371/journal.pone.0001286 (http://www.plosone.org/doi/pone.0001286)


Story Source:

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


Cite This Page:

Public Library of Science. "Aging In Salmon Depends On Choosy Bears." ScienceDaily. ScienceDaily, 13 December 2007. <www.sciencedaily.com/releases/2007/12/071211234007.htm>.
Public Library of Science. (2007, December 13). Aging In Salmon Depends On Choosy Bears. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2007/12/071211234007.htm
Public Library of Science. "Aging In Salmon Depends On Choosy Bears." ScienceDaily. www.sciencedaily.com/releases/2007/12/071211234007.htm (accessed July 25, 2014).

Share This




More Plants & Animals News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Boy Attacked by Shark in Florida

Boy Attacked by Shark in Florida

Reuters - US Online Video (July 24, 2014) An 8-year-old boy is bitten in the leg by a shark while vacationing at a Florida beach. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Dogs Appear To Become Jealous Of Owners' Attention

Dogs Appear To Become Jealous Of Owners' Attention

Newsy (July 23, 2014) A U.C. San Diego researcher says jealousy isn't just a human trait, and dogs aren't the best at sharing the attention of humans with other dogs. Video provided by Newsy
Powered by NewsLook.com
Professor Creates Site Revealing Where People's Cats Live

Professor Creates Site Revealing Where People's Cats Live

Newsy (July 23, 2014) ​It's called I Know Where Your Cat Lives, and you can keep hitting the "Random Cat" button to find more real cats all over the world. Video provided by Newsy
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:
from the past week

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