Featured Research

from universities, journals, and other organizations

Balanced harvesting of fish communities: What are the consequences?

Date:
December 6, 2013
Source:
Technical University of Denmark (DTU)
Summary:
“Balanced harvesting” is a new proposal to the management of fished populations. The concept is to balance the fishery with the production of new biomass. A balanced fishery is unselective and targets mainly small, and often immature individuals, and to a much smaller degree large fish. It is a controversial concept, as this fishing strategy allows young fish to be caught before they have a chance to reproduce.

The authors found that unselective balanced fishing, where individuals are exploited in proportion to their productivity, produces a slightly larger total maximum sustainable yield than the other exploitation patterns and, for a given yield, the least change in the relative biomass composition of the fish community.
Credit: Technical University of Denmark (DTU)

"Balanced harvesting" is a new proposal to the management of fished populations. The concept is to balance the fishery with the production of new biomass. A balanced fishery is unselective and targets mainly small, and often immature individuals, and to a much smaller degree large fish. It is a controversial concept, as this fishing strategy allows young fish to be caught before they have a chance to reproduce.

In a new study published in the Proceedings of the Royal Society B (Biological Sciences), Nis S. Jacobsen, Henrik Gislason and Ken H. Andersen use a size- and trait-based model to compare balanced harvesting with traditional selective harvesting, which protects juvenile fish from fishing.

"We use a fish community model where fish are resolved in sizes, from egg to spawning adults, to investigate the consequences of this pattern compared to more traditional fishing patterns. We find that unselective "balanced harvesting" can provide a slightly larger total protein catch and fewer disturbances to the fish community than a traditional selective fishing pattern," explains Ph.D.-student Nis S. Jacobsen, DTU Aqua.

In the article four different exploitation patterns, generated by combining selective or unselective harvesting with balanced or unbalanced fishing, are compared. The authors find that unselective balanced fishing, where individuals are exploited in proportion to their productivity, produces a slightly larger total maximum sustainable yield than the other exploitation patterns and, for a given yield, the least change in the relative biomass composition of the fish community. Because fishing reduces competition, predation and cannibalism within the community, the total maximum sustainable yield is achieved at higher exploitation rates than expected from single species models.

Very small fish

However, the yield from unselective balanced fishing is dominated by small individuals, whereas selective fishing produces a much higher proportion of large individuals in the yield. Although unselective balanced fishing is predicted to produce the highest total catch and the lowest impact on trophic structure, it is effectively a fishery predominantly targeting small forage fish.

"The catch is comprised of mostly very small fish that return low prices and are unsuitable for a Western market. So, even though balanced harvesting has some good properties it is probably an unlikely strategy for Western fisheries management as such," Nis S. Jacobsen, DTU Aqua explains


Story Source:

The above story is based on materials provided by Technical University of Denmark (DTU). Note: Materials may be edited for content and length.


Journal Reference:

  1. N. S. Jacobsen, H. Gislason, K. H. Andersen. The consequences of balanced harvesting of fish communities. Proceedings of the Royal Society B: Biological Sciences, 2013; 281 (1775): 20132701 DOI: 10.1098/rspb.2013.2701

Cite This Page:

Technical University of Denmark (DTU). "Balanced harvesting of fish communities: What are the consequences?." ScienceDaily. ScienceDaily, 6 December 2013. <www.sciencedaily.com/releases/2013/12/131206091421.htm>.
Technical University of Denmark (DTU). (2013, December 6). Balanced harvesting of fish communities: What are the consequences?. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2013/12/131206091421.htm
Technical University of Denmark (DTU). "Balanced harvesting of fish communities: What are the consequences?." ScienceDaily. www.sciencedaily.com/releases/2013/12/131206091421.htm (accessed July 23, 2014).

Share This




More Plants & Animals News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
San Diego Zoo Welcomes New, Rare Rhino Calf

San Diego Zoo Welcomes New, Rare Rhino Calf

Reuters - US Online Video (July 21, 2014) An endangered black rhino baby is the newest resident at the San Diego Zoo. Sasha Salama reports. Video provided by Reuters
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
$23.6 Billion Awarded To Widow In Smoking Lawsuit

$23.6 Billion Awarded To Widow In Smoking Lawsuit

Newsy (July 20, 2014) Cynthia Robinson claims R.J. Reynolds Tobacco Company hid the health and addiction risks of its products, leading to the death of her husband in 1996. 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