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Capturing grey seals alive with trapnets

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Hunting grey seals (Halicoerus grypus) is one of the most difficult forms of hunting in Finland. Regulating grey seal population only with hunting is not likely to lead to the desired results. Only half of the hunting licences are used annually. In 2007, in close cooperation with professional fishermen and trap-net manufacturers, FGFRI developed a special design that can be connected to a so-called push-up trap. The aim was to come up with a trap-net design that enables fishing while also allowing seals to be caught alive.
Benefits of capturing seals alive with trap-nets:

1.Those grey seals that have learned how to use trap-nets for finding food become caught.
2.All ringed seals (Pusa hispida) are released alive.
3.Those grey seals exceeding the hunting quota can released alive.
4.It is possible to slaughter a grey seal caught in a trap-net in an ethical way, and its valuable resources can be used (meat, train oil, skin, bones).


Experiments are being carried out between June and October 2007 in the sea area of Pori and Merikarvia in cooperation with local professional fishermen. Two groups of fishermen using identical trap-nets are participating in the research project. The push-up traps needed for the project are rented from the fishermen. The fishermen taking part in the study are responsible for examining and maintaining the traps during the whole experimental period.

Most of the grey seals caught in the trap-nets are released, and only a few are shot in order to collect samples and verify the correct functioning of the method. The GSM equipment installed at the back of the trap-net sends a signal when a seal is caught. Shooting is carried out by fishermen with valid firearms certificates and a proper weapon for hunting. Shooting a grey seal when it comes up to breathe in the roof part of the trap-net allows the killing it in a rapid and ethically acceptable manner. The dead seal falls to the bottom of the trap-net, from where it is transferred into the boat. Fast and appropriate handling of the dead seal is then essential in order to ensure the high quality of seal products. This handling is carried out by the Game Districts of Satakunta and Swedish Ostrobothnia, in cooperation with professional fishermen familiar with seal handling.

Underwater videotape monitoring of the behaviour of fish and seals

Designing and testing of the trap equipment involve recording of the behaviour of seals and fish on videotape. This information is essential in order to develop the critical structures of the traps. Recording is carried out by means of two concurrent underwater camera systems, one with equipment in which the image is transmitted wirelessly (WLAN/GSM net) to a computer at the harbour in real time, the other with a system in which the image material from three different video cameras is stored on a hard disk attached to the seal trap. On the latter, the image material cannot be viewed in real time. Instead, the data is extracted and analysed at the harbour after the traps have been examined.

Researcher in charge

Lehtonen Esa, Finnish Game and Fisheries Research Institute

Other persons

Ojala Veli-Pekka, Suuronen Petri, Mäkelä Tapio


Live-capture of grey seals in a modified salmon trap
Lehtonen, Esa, Suuronen, Petri
Fisheries Research 102 (2010) 214-216

Project phase: Completed


Source: FGFRI Projectnet


© 2010 Finnish Game and Fisheries Research Institute.