Navigation Links
Gray seals consume as much fish as the fishing industry catches
Date:4/2/2012

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 Lundstrm.

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 Lundstrm.

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 Lundstrm.

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


'/>"/>

Contact: Karl Lundstrm
karl.lundstrom@slu.se
46-104-784-138
University of Gothenburg
Source:Eurekalert  

Related biology news :

1. Mercury pollution causes immune damage to harbor seals
2. NTU seals global partnerships on environmental sciences R&D
3. Fossil evidence of missing link in the origin of seals, sea lions, walruses found in Canadian Arctic
4. Seals quickly respond to gain and loss of habitat under climate change
5. Harbor seals whiskers as good at detecting fish as echolocating dolphins
6. High-tech software, umanned planes allow scientists to keep tabs on Arctic seals
7. NOAA scientists find killer whales in Antarctic waters prefer weddell seals over other prey
8. Seals sense shapes using their whiskers to feel wakes
9. Seals show different levels of parenting skills
10. New study illustrates the physics behind great white shark attacks on seals
11. Harp seals on thin ice after 32 years of warming
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Gray seals consume as much fish as the fishing industry catches
(Date:5/16/2017)... , May 16, 2017  Veratad Technologies, LLC ... of online age and identity verification solutions, announced today ... Identity Conference 2017, May 15 thru May 17, 2017, ... Building and International Trade Center. Identity ... globe and in today,s quickly evolving digital world, defining ...
(Date:4/18/2017)... Calif. , April 18, 2017  Socionext Inc., a global ... of a media edge server, the M820, which features the company,s ... recognition software provided by Tera Probe, Inc., will be showcased during ... at the NAB show at the Las Vegas ... ...
(Date:4/11/2017)... 11, 2017 Research and Markets has announced ... report to their offering. ... global eye tracking market to grow at a CAGR of 30.37% ... Tracking Market 2017-2021, has been prepared based on an in-depth market ... landscape and its growth prospects over the coming years. The report ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... Proscia Inc ., a ... Webinar titled, “Pathology is going digital. Is your lab ready?” with Dr. Nicolas ... practices and how Proscia improves lab economics and realizes an increase in diagnostic ...
(Date:10/11/2017)... ... October 11, 2017 , ... Disappearing forests and increased ... of over 5.5 million people each year. Especially those living in larger cities are ... - based in one of the most pollution-affected countries globally - decided to take ...
(Date:10/10/2017)... ... ... San Diego-based team building and cooking events company, Lajollacooks4u, has unveiled a ... new look is part of a transformation to increase awareness, appeal to new markets ... It will also expand its service offering from its signature gourmet cooking classes and ...
(Date:10/10/2017)... , ... October 10, 2017 , ... Dr. Bob Harman, ... his local San Diego Rotary Club. The event entitled “Stem Cells ... and had 300+ attendees. Dr. Harman, DVM, MPVM was joined by two human ...
Breaking Biology Technology: