Several thousand whales lose their lives in Norwegian fishing every year. It is usually porpoises that get stuck in the nets. These are relatively small, at 1.5 metres. But in recent years, an increasing number of fishermen have also had much larger species unsolicited in their nets and other fishing gear. – It has become a bigger and bigger problem that large whales get stuck in nets, says research manager Martin Biuw at the Institute of Marine Research. This mainly applies to killer whales and humpback whales. – But there have also been more fin whales and sperm whales, says Biuw. Large whales becoming entangled in fishing nets is a growing problem. Now scientists are working to scare them away with sounds that make the whales splash away. Video: Photo: Havforskningsinstituttet / Audun Rikardsen Together with researchers from UiT, Norway’s Arctic University, he is now working on developing a tool to keep the whales away from the nets. The need to find a way to scare them away has been there for a long time. Last year, a fisherman in Finnmark spent 20 minutes freeing a humpback whale and this summer a fisherman in Nordland found a drowned pilot whale in the net. Now the researchers have found that sound can be the solution. – The idea is to test different alarm sounds to scare the whale away, says Biuw. He says that the desired effect can be compared to the one you feel when you watch a horror film and suddenly have to jump up on the sofa. – It must be a sound that is so strong that it is frightening here and there, but not harmful, he says. Research leader Martin Biuw (right) together with marine biologist Audun Rikardsen at UiT. Photo: Audun Rikardsen / UiT Not dangerous for the whale On the killer whales, the alarm sound has already started to work, says Biuw. The large mammals swim away when it is played. – Often what happens when we play the sound for the killer whales is that they quickly disappear, and lie down about 100 meters away. – It’s ideal, because we don’t need to scare them so far away. We are close to a solution there, he says. The researchers haven’t quite figured out how to scare the humpback whales yet. Photo: Espen Bergersen However, the humpback whale is a little more difficult to scare, and is not as sensitive to sound, according to Biuw. – It is less sensitive. We have made it react, but there is still more work needed to find a solution. To understand how the whales react to the sounds, they have attached cameras, hydrophones and sensors to them. – Then the hydrophone can pick up the sound and see how they respond. With video you can see how they move. – The sound is a broad-spectrum noise at several different frequencies. It should come suddenly, not stealthily. It is to make it appear as frightening as possible. With a carbon rod several meters long, the camera and sensors are attached to the whale with suction cups. Biuw says they have to “sneak in” to get the equipment attached. Photo: Thomas Goetz – But is it okay to scare the whales then? Can’t they be scared? – The point is that it is an unconscious scare reaction. A bit like a “jump scare”. – It is better than them getting stuck in the net and possibly dying, says Biuw. Many whales have died. Biuw explains that the intake of more and more whales in winter in northern Norway has made the problem worse. The whales often seek out the nets because it is an easy source of food. – Ten killer whales and eight humpback whales have died on average in the last ten years. Many more get stuck or are injured. It is perhaps only 5 percent who die. With that calculation, there are just over 350 whales that get stuck, injure themselves or die in fishing nets every year. In addition to being harmful to the animals themselves, it is expensive and tedious for the fishermen. – The humpback whale in particular can cause great damage to the equipment, and creates a lot of work for the fishermen. They often have to take action quickly when the whales come to the rescue. Then they also lose the entire catch out of the net, says Biuw. Together with actors in the fishing industry, they eventually hope to be able to use sounds to scare all kinds of whales far away from the fishing boats.
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Researchers want to scare whales away from fishing boats so they don’t end up in nets – news Troms and Finnmark
