Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Growing seal population threatens small-scale fishing

10.05.2011
Seals and the fishing industry compete for fish of all types – no matter whether it is salmon, whitefish, herring or cod. Seal-safe fishing gear is the most sustainable solution, and we need knowledge about the behaviour of fish and seals in order to develop such gear. This is the conclusion reached by scientists at the University of Gothenburg, Sweden.

Coastal and small-scale fishing in Sweden has fallen in recent decades as a result of several factors; mainly an increase in the seal population, threats to fish species, and logistical problems. As the number of seals increases, the damage they cause to fish and to fishing gear becomes more serious. The use of seal-safe fishing gear has, therefore, major economic significance.

“Some alternative seal-safe fishing gear is commercially available, developed in collaboration between scientists and the fishing industry. But if we are to develop this further, we need to learn more about how seals behave and how they treat the equipment. We have filmed seal-safe traps and seen how certain seals become specialists in attacking them”, says Sara Königson, of the Department of Marine Ecology at the University of Gothenburg. She has studied seals and the fishing industry at the Institute of Coastal Research of the Swedish Board of Fisheries.

Seal hooligans hunt at seal-safe fishing gear
Some seals have learned to hunt at the push-up trap that has been developed for the small-scale fishing of salmon and whitefish in the Baltic. The trap has a seal-safe chamber in which the caught fish are collected, supposedly safe from the seals. Despite this, damage caused by seals has not been fully eliminated. Some seals, quite simply, have managed to figure out the equipment, and overcome it. By filming seals who hunt close to the trap, the scientists could identify ten individuals who had become specialists in hunting in the trap. These seals returned to the site over a long period.

“Since we now know that it is only certain seals who are responsible for the damage, we have the chance of limiting the damage in a certain region, simply by removing these individuals.”

Successful use of cod pots
Small-scale fishing with pots is another example of a sensitive fishing technique that can be protected from attack by seals. One of the intermediate goals of the project has been to study whether pot fishing can be an alternative to net fishing: whether it is possible to fish for cod on a commercial basis using cod pots. The pots that have been developed attract the fish using bait, just as hook-and-line fishing.

“Catches in the pots are just as large as those taken using nets, in a region that suffers from seal damage, and the mesh size of the pots means that they are selective. Furthermore, their impact on the environment is small. The fish are caught alive, and this means that the quality is good and the price is high. The yields of baited fishing gear, however, are influenced by many factors. Currents, temperature, bottom topography, etc., all probably play important roles, as do the availability of food and the maturity of the fish. We still don’t know which factors affect the yield most strongly”, says Sara Königson.

The research has been conducted from Hudiksvall in the north to Simrishamn in the south.

The thesis, Seals and fisheries: a study of the conflict and some possible solutions, was successfully defended at a public defence on 29 April.

Journal: Fisheries Research 107, 1-3: 239-244
Title: Effects of escape windows on the capture of cod in floating pots
Authors: Ovegård, M., Königson, S., Persson, A., and Lunneryd, S-G. 2010.
Sara Königson, Department of Marine Ecology, University of Gothenburg and
the Institute of Coastal Research of the Swedish Board of Fisheries.
+46 (0)70 2215 915 +46 (0)70 2215 915
+46 (0)5 2318 709 +46 (0)5 2318 709
sara.konigson@fiskeriverket.se

Helena Aaberg | idw
Further information:
http://hdl.handle.net/2077/25022
http://www.youtube.com/user/naturvetenskap09

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>