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 At last, butterflies get a bigger, better evolutionary tree
16.02.2018 | Florida Museum of Natural History

nachricht New treatment strategies for chronic kidney disease from the animal kingdom
16.02.2018 | Veterinärmedizinische Universität Wien

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>