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 April 17, 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 April 17, 2014).

Share This



More Plants & Animals News

Thursday, April 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Great British Farmland Boom

The Great British Farmland Boom

Reuters - Business Video Online (Apr. 17, 2014) Britain's troubled Co-operative Group is preparing to cash in on nearly 18,000 acres of farmland in one of the biggest UK land sales in decades. As Ivor Bennett reports, the market timing couldn't be better, with farmland prices soaring over 270 percent in the last 10 years. Video provided by Reuters
Powered by NewsLook.com
Flamingo Frenzy Ahead of Zoo Construction

Flamingo Frenzy Ahead of Zoo Construction

AP (Apr. 17, 2014) With plenty of honking, flapping, and fluttering, more than three dozen Caribbean flamingos at Zoo Miami were rounded up today as the iconic exhibit was closed for renovations. (April 17) Video provided by AP
Powered by NewsLook.com
Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
Powered by NewsLook.com
Could Even Casual Marijuana Use Alter Your Brain?

Could Even Casual Marijuana Use Alter Your Brain?

Newsy (Apr. 16, 2014) A new study conducted by researchers at Northwestern and Harvard suggests even casual marijuana use can alter your brain. 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