Featured Research

from universities, journals, and other organizations

Grey seals in Baltic Sea consume as much fish as the fishing industry catches, research finds

Date:
April 2, 2012
Source:
University of Gothenburg
Summary:
The grey seals in the Baltic Sea compete for fish with the fishing industry. The seals locally eat about the same quantities of cod, common whitefish, salmon, sea trout and eel as those taken by fishermen, according to new research.

The gray seals in the Baltic Sea compete for fish with the fishing industry.
Credit: Photo: University of Gothenburg

The grey seals in the Baltic Sea compete for fish with the fishing industry. The seals locally eat about the same quantities of cod, common whitefish, salmon, sea trout and eel as those taken by fishermen. This is the conclusion from research carried out at the University of Gothenburg, Sweden.

Competing with the fishing industry

The grey seals in the Baltic Sea eat largely the same species and the same sizes of fish as those taken by the fishing industry. So even if the amount of fish eaten by seals is small relative to the total amount of fish caught in the Baltic Sea, the seals' dietary habits may have a major impact on the local availability of fish in the areas where they are common.

"If you compare the estimated consumption of fish by grey seals in their main range in Sweden, which is north of the Kalmar Sound, it is of the same order of magnitude as the total catch taken by Swedish professional and leisure fishermen in the same area," says scientist Karl Lundström.

Increasing population of seals

The grey seal was common at the beginning of the 20th century, but was hard hit by hunting and by environmental toxins, and only a remnant remained in the 1970s. However, the seal population has grown continuously since the middle of the 1980s, and this has led conflicts with the fishing industry.

"The conflict has mainly centred on the way in which seals eat from and destroy fishing gear, but as the number of seals has increased the possible competition for food resources has come into focus," says Karl Lundström.

Study of dietary habits

The scientists have studied the dietary habits of the seals in order to understand the role they play on the ecosystem, and how they influence the surroundings. This has been done not only by investigating prey remains in the digestive tracts of the seals but also by analysing the composition of fatty acids in their blubber. The fatty acid composition in the seals' blubber reflects the composition of fatty acids in the fish species that they eat, and can give an idea of the dietary patterns of the seals over a long period.

It became clear that the diet of grey seals differs between the northern and the southern Baltic. Herring was the most common food eaten by all seals, followed by common whitefish in the Gulf of Bothnia and sprat in the main body of the Baltic Sea. The diet of young seals differed from that of old seals, and the feeding habits of males differed from that of females.

"We have now developed useful methods and created a good starting point for further studies into the dietary habits of seals. We can also investigate the significance they have as fish-eating predators at the top of the marine ecosystem. By combining the methods that I have used with other techniques, it will be possible to increase our knowledge further. More closely focussed investigations in particularly interesting regions will also be needed, both for grey seals and ringed seals in the Baltic Sea and for common seals in the Kattegat and Skagerrak area," says Karl Lundström.

This is the first comprehensive investigation into the diet of the grey seal in the Baltic Sea since the 1970s.

Further info: http://gupea.ub.gu.se/handle/2077/28131


Story Source:

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


Cite This Page:

University of Gothenburg. "Grey seals in Baltic Sea consume as much fish as the fishing industry catches, research finds." ScienceDaily. ScienceDaily, 2 April 2012. <www.sciencedaily.com/releases/2012/04/120402112826.htm>.
University of Gothenburg. (2012, April 2). Grey seals in Baltic Sea consume as much fish as the fishing industry catches, research finds. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2012/04/120402112826.htm
University of Gothenburg. "Grey seals in Baltic Sea consume as much fish as the fishing industry catches, research finds." ScienceDaily. www.sciencedaily.com/releases/2012/04/120402112826.htm (accessed April 16, 2014).

Share This



More Plants & Animals News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Ebola Outbreak Now Linked To 121 Deaths

Ebola Outbreak Now Linked To 121 Deaths

Newsy (Apr. 15, 2014) — The ebola virus outbreak in West Africa is now linked to 121 deaths. Health officials fear the virus will continue to spread in urban areas. Video provided by Newsy
Powered by NewsLook.com
In Washington, a Push to Sterilize Stray Cats

In Washington, a Push to Sterilize Stray Cats

AFP (Apr. 14, 2014) — To curb the growing numbers of feral cats in the US capital, the Washington Humane Society is encouraging residents to set traps and bring the animals to a sterilization clinic, after which they are released.. Duration: 02:29 Video provided by AFP
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