The researchers have found a sound that makes killer whales stay away from fish nuts – NRK Nordland

It has long been a big problem that quail got stuck in fishing nets.

Namely, it can become dangerous for both quail and fishermen when a quail visits a fishing boat for a free fish meal.

– There is an increasing problem with stingrays parasitizing fisheries, says stingray researcher Audun Rikardsen at the Norwegian Institute of Marine Research (HI).

– It is dangerous for the quail, which can become entangled in fishing nets and drown.

For the fishermen, it means ruined bills with big costs and a lot of extra work.

For several years, researchers have tried to find a solution.

Now they are on the trail of something.

Sounds like a solution

Researchers from several institutes; The Institute of Marine Research, the University of Tromsø and the University of St. Andrews in Scotland have worked together to find a solution to the problem.

Until now, they have worked with humpback whales and killer whales, which are two of the whales that purse seiners struggle with the most.

– We have found a sound that seems to keep killer whales away from herring nuts.

That’s what Maria Tenningen says, who has been the project manager for the project.

– On killer whales it seems to work, but for humpback whales we are not quite there yet.

How did they find it out?

1. The researchers first conducted a controlled experiment by tagging humpback whales and killer whales with tags that register movement and direction, and exposed the whales to different types of sound recordings to see what they reacted to.
2. Then they did the same in the vicinity of fishing boats that fish. In advance, they had selected some sounds that they played when there was distress at the fishing boats.
3. Then they simply counted how many quails were there before, during and after they played the sound.

It is the Scottish researchers who have developed the sound system that keeps the anguish away.

– The killer whales disappeared in whole or in part during filming, says Tenningen.

A “fishing alarm”

But how does such an alarm actually sound?

They are called acoustic alarms, and simply work as an alarm, explains Audun Rikardsen at UiT.

– There is not a single sound that is harmful to the ants. It’s not a loud sound, it’s just an irritating sound that causes a reflex, says Rikardsen:

– Almost as if you were rubbing styrofoam against the window.

Sound is not just sound. If a sound is frightening at first, but lasts a long time, it can have the opposite effect:

Then it can act as a food bull, when the ants realize that it is not dangerous.

– The sound we are testing, however, is a sound that they should not get used tosays Rikardsen.

When they played the sound for killer whales, they saw that 85 percent of the pain went away. But when they stopped playing the sound they came back after about 10 minutes.

– We don’t want to scare the whales far away, but that the whales should stay away from the fishery when they fish.

– Must escape from an area with herring

The researchers say that the fishermen they have spoken to are very interested in the new solution.

But then something has to happen with how you use the alarm, says Fiskar Arnfinn Arnøy.

He is a herring fisherman and fishes both in Nordland and Troms.

The researchers have so far used a loudspeaker in a thick cable which they have sunk down. It will be too difficult for the fishermen.

– Then we would get the cable in the propeller, says Arnøy.

He wants something that is connected to the hull, or something that can be delivered as bottom equipment such as sonar.

– We almost have to run away from areas with a lot of herring, if there is a lot of quail. Then the chance is too great that we will get the anguish in the bill, he says.

He therefore warmly welcomes the researchers’ solution.

– It would have been perfect to keep them away until we have managed to get the bill together.

Strict rules for sound

Although the researchers have had success with killer whales so far, they have struggled more with knee pain.

– Why doesn’t it work on them?

– Knølkval is less sensitive to sound and listens at slightly different frequencies, says Rikardsen.

Tanningen adds that they know more about the hearing of killer whales than humpback whales, and that this is part of the reason why it is difficult to find the right sound for humpback whales.

She also says that there are strict requirements for the volume used, so that it is not harmful to the animals.

– Kvalen uses sound to communicate with each other and find food. You have to be very careful so that you don’t disturb that activity.

Eventually, the researchers hope to find solutions that can be linked directly to the fishing equipment the fishermen already have, such as the sonar on the boats.