Featured Research

from universities, journals, and other organizations

Cod resurgence in Canadian waters

Date:
July 28, 2011
Source:
Queen's University
Summary:
Cod and other groundfish populations off the east coast of Canada are showing signs of recovery more than 20 years after the fisheries collapsed in the early 1990s, according to new research.

Haddock and redfish collected during a Department of Fisheries and Oceans survey of the Canadian Scotian Shelf.
Credit: Image courtesy of Queen's University

Cod and other groundfish populations off the east coast of Canada are showing signs of recovery more than 20 years after the fisheries collapsed in the early 1990s, according to research published July 27 in Nature.

"This early-stage recovery represents a long ecological transition for an ecosystem that was pushed out of balance and that is gradually moving back into balance," says William Leggett, a professor in the Department of Biology, former principal at Queen's, and an expert in the dynamics of large marine ecosystems.

This study is the first to show evidence of a recovery at the multi-species level and delve into the underlying ecological mechanisms facilitating the recovery.

The researchers hypothesize that the 20-year delay in recovery was caused by a reversal of fish predator and prey roles. When large-bodied fish like cod were dominant, they fed on smaller forage fish species. However, the overfishing of cod and other groundfish populations meant that these smaller forage fish had the opportunity to prey on large-bodied fish species in their earliest life-stages, preventing these populations from recovering their numbers.

This absence of large-bodied fish predators resulted in the forage fish population ballooning by 900 per cent and ultimately outstripping its food sources. The subsequent decline in forage fish numbers has been vital for the recovery of the cod and haddock populations.

While this recovery is positive and bodes well for other collapsed fisheries, Dr. Leggett and research colleague Jonathan Fisher are quick to note that the process is not straightforward. Cod populations are now at around 34 per cent of the level that was typical when commercial fishing was flourishing in the 1970s and 1980s. Haddock, on the other hand, now exceeds its historical levels and is playing a more dominant role.

"It's difficult to say if this switch may have any long-term implications," explains Dr. Fisher, a postdoctoral fellow in the Department of Biology. "This system may return to its historical character, but there's also the possibility that it won't and that another species will dominate. Only time will tell."

This research was conducted in collaboration with Kenneth Frank and Brian Petrie from the Bedford Institute of Oceanography and was funded by the Natural Sciences and Engineering Research Council of Canada.


Story Source:

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


Journal Reference:

  1. Kenneth T. Frank, Brian Petrie, Jonathan A. D. Fisher, William C. Leggett. Transient dynamics of an altered large marine ecosystem. Nature, 2011; DOI: 10.1038/nature10285

Cite This Page:

Queen's University. "Cod resurgence in Canadian waters." ScienceDaily. ScienceDaily, 28 July 2011. <www.sciencedaily.com/releases/2011/07/110727151438.htm>.
Queen's University. (2011, July 28). Cod resurgence in Canadian waters. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2011/07/110727151438.htm
Queen's University. "Cod resurgence in Canadian waters." ScienceDaily. www.sciencedaily.com/releases/2011/07/110727151438.htm (accessed July 30, 2014).

Share This




More Plants & Animals News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Raw: Otters Enjoy Water Slides at Japan Zoo

Raw: Otters Enjoy Water Slides at Japan Zoo

AP (July 30, 2014) River otters were hitting the water slides to beat the summer heatwave on Wednesday at Ichikawa City's Zoological and Botanical Garden. (July 30) 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