Featured Research

from universities, journals, and other organizations

Over fishing tips scales towards a fish population of slow growing, couch potatoes

Date:
September 12, 2012
Source:
Deakin University
Summary:
Fish populations around the world could soon be full of slow growing, unproductive 'couch potatoes' if the current levels of intensive fishing continue, according to new research. Scientists found that faster growing fish, regardless of their size, fall prey to fishing nets at twice the rate of slower growing fish.

Peter Biro with an adult trout.
Credit: Image courtesy of Deakin University

Fish populations around the world could soon be full of slow growing, unproductive 'couch potatoes' if the current levels of intensive fishing continue, according to Deakin University research.

Associate Professor Peter Biro, an ecologist with Deakin's School of Life and Environmental Sciences, has found that faster growing fish, regardless of their size, fall prey to fishing nets at twice the rate of slower growing fish.

According to Associate Professor Biro, this could force a human-driven evolutionary shift to populations of slow growing, unproductive, couch potatoes of the fish world which would have serious implications for fish stocks.

"Fisheries are already declining around the world. If we continue to harvest the fast growing fish, we run the risk of forcing an evolutionary shift toward slow growing fish, as fish growth rates are significantly underpinned by genetics. Slow growing fish are less fertile, so ultimately fish supplies will decline," he explained.

For the study, Associate Professor Biro simulated a wild fishery by stocking four small lakes in British Columbia, Canada, each with equal numbers of slow, medium and fast-growing wild origin rainbow trout. The lakes previously contained no fish, experienced no predation by birds, were remote and were closed to fishing. After allowing the fish to grow between spring and autumn, each lake was harvested using gillnets, a common commercial fishing method whereby nets are cast over large areas to catch the largest possible number of fish.

"Even though I sampled all areas of the lake randomly, and the gear was not selective on size, fast-growers were harvested at twice the rate of slower-growing individuals," he said.

"I believe the faster growers are harvested at a higher rate because they are more active, aggressive and bold. Essentially to maintain a fast growth trajectory individuals have got to get out and about, they can't be fast growing if they sit underneath a log cowering. The fast-growers are likely swimming around more, searching out food to a greater extent than slow-growers and are therefore more likely to encounter the fishing nets.

"What I was also interested to find was that the catch rates were not affected by the size of the fish, for example, the fast growing small fish were caught at twice the rate of the slow growing small fish."

Associate Professor Biro said that what is happening in the fishing industry is a stark contrast to the approach with agriculture.

"In agriculture selective breeding is used to increase production; more eggs, more meat, more milk for example. By contrast, the way we harvest in wild fisheries we achieve the exact opposite; we are pushing the fish populations to be slower growing and therefore less productive," he said.

Associate Professor Biro is not optimistic that commercial, or even recreational, fishers will curb their behaviour in light of his research results.

"I believe that reducing harvest rates is, unfortunately, the only way to preserve fish stocks into the future, which is not something that those making a living from fishing are likely to agree to. I am not optimistic that this information is going to be used before the problem comes to a head, and we are left with few fish that are slow growing, and have little capacity to bounce back from overexploitation."


Story Source:

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


Journal Reference:

  1. Peter A. Biro. Are most samples of animals systematically biased? Consistent individual trait differences bias samples despite random sampling. Oecologia, 2012; DOI: 10.1007/s00442-012-2426-5

Cite This Page:

Deakin University. "Over fishing tips scales towards a fish population of slow growing, couch potatoes." ScienceDaily. ScienceDaily, 12 September 2012. <www.sciencedaily.com/releases/2012/09/120912093831.htm>.
Deakin University. (2012, September 12). Over fishing tips scales towards a fish population of slow growing, couch potatoes. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2012/09/120912093831.htm
Deakin University. "Over fishing tips scales towards a fish population of slow growing, couch potatoes." ScienceDaily. www.sciencedaily.com/releases/2012/09/120912093831.htm (accessed September 22, 2014).

Share This



More Plants & Animals News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
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