Fish stock survey
In addition to knowledge of technical research methods, VisAdvies staff have extensive experience in setting fykes and sampling with seine, Pelagic trawl and electrofishing. Surveys on larger water bodies are conducted in cooperation with a regular partner.
Electrofishing is conducted in fish stock surveys. Electrofishing is conducted from a boat or wading with a mobile device. In electrofishing, a generator is used to apply an electric current into the water. The net connected to the generator is the positive pole, while a cable or mesh acts as the negative pole. The fish that are near the net are stunned by the current and can be easily scooped up. This method is very suitable for fishing in places where there are many obstacles, such as vegetated riparian zones.
The seine is used in fish stock surveys. Using a boat, the seine is lowered into the water in a semi-circle. The seine is then slowly pulled close at the water's edge. VisAdvies uses seines of different sizes, depending on the body of water.
The pelagic trawl is used in fish stock surveys. The trawl is pulled forward with two boats at approximately 5 km/h. The trawl can be used to fish freely floating in the water as well as fishing close to the bottom.
Fykes are passive fishing gears that rely on fish behavior to enter the net and get caught. These nets can be customized in terms of size, mesh size, and placement to optimize the capture of the target species while minimizing unintended bycatch. They are typically set in strategic locations within the waterbody or in transects. Fykes are used primarily in fish migration monitoring and fish stock studies.