Tuning in to the sounds of the sea

However, the recent introduction of commercially-available scientific broadband echo sounders has been a game-changer for the researchers – and the fishing industry. Compared with traditional sonar, the broadband system produces at least 100 times as much data, making it an invaluable tool for gathering large amounts of high-quality information.

CRIMAC’s research will use this technology to create next-generation acoustic tools which not only reveal the size of a school of fish, but also information about the species and the length of the individual animals. Each species has its own ‘acoustic dialect’ – the precise echo pattern it produces – and by identifying these signatures, researchers can compile a library of data which can then be drawn on by fishing boat skippers and scientists.

FROM PLANKTON TO PREDATORS

The implications of this increased understanding of what is in our oceans are hugely significant. Improved identification of fish can lead to more efficient and responsible fishing by preventing unwanted bycatch. The information from the echo sounders will provide vital data to fish farms about fish behaviour, helping to improve animal welfare and optimise production. The precise monitoring will also enable the measurement of the changing underwater ecosystems and provide data on the abundance and distribution of key undersea species, from plankton to top predators.

“We have worked with this wideband technology for 11 years now so we’ve already made the errors we might have made if this was the first year of the project,” says Egil. “We have everything available and now we want to start learning about what kind of improvements this technique can give.

“We want to start studying what kind of spectrum we get from different organisms in the ocean to teach ourselves how jellyfish, for example, will reflect in the frequency domain. We are going to learn and put this in the collective memory.

“If the scientists have a better tool to have better knowledge on the ecosystem and its components then we can give better advice to the fishery. Each fishing vessel has a quota and a permit for what they can fish, so bycatch is a big problem in some places. This system can help the fisherman do a better job with his quota.”

The data used in the project will be gathered using a combination of long-range observations from vessels and short-range inspections from probes and drones fitted with miniaturised broadband echosounders. CRIMAC will study how the surface and underwater drones can improve scientific surveys and also be used in active fisheries.

To accurately verify the acoustic recordings, the researchers will use the Scantrol DeepVision – a fish ‘photobooth’ inside the trawl – which is equipped with active selection and open/close systems. This will enable the team to take specific samples and improve their observations.

The research vessel G.O. Sars put to sea in mid-November to begin collecting information. Gathering high-quality data will be vital to the project’s success and the ship as well an unmanned surface drone were equipped with state-of-the-art wideband echosounders. Technology for efficient communication between the deployed drone and the vessel was tested and well received during the research cruise.

“We’re going to two specific areas where we know that there’s around four million tonnes of herring,” says Egil. “We’re going to train this system and collect data for the library of experience.”

TRACKING A CHANGING WORLD

The investment in CRIMAC as a long-term project provides the time and resources to complete in-depth analyses which are expected to lead to the publication of pioneering research and the development of new products.

You can look into small details and go into extra subjects which even weren’t in the original application. It may also be a platform for new exciting projects!

“This will give us the opportunity to investigate the ecosystem in much more detail. Ecosystems change – it happened around 20 years ago in the North Sea. Maybe in another 20 years it will cool down and the North Sea will come back into better production. Those rapid changes and signals, we have to capture them with our new system.

“With the continuous monitoring we have in many places, we can monitor timescales much more accurately than before. It’s like meteorology. You have a model, you supply it with good data and then you can understand if a big storm is coming and you can prepare.”

Simrad was at the forefront of the evolution of the industry and introduced the first commercial ASDIC fish-finding sonar in 1953. In 1969, it provided the echo sounders for the newly built G.O. Sars, the same ship which will gather data for CRIMAC. The research vessel was also fitted with the very first computer made in Norway thanks to a funding allowance provided by the country’s King Olav V.

Over the following decades, Simrad continued to push the boundaries and deliver new innovations, including improvements in the broadband sonar which will be used by CRIMAC. Simrad was acquired by Kongsberg in 1996 and during the 2000s, the focus of the work with IMR has expanded from measuring a few commercially available fish stocks to studying the full marine ecosystem.

Today Simrad by Kongsberg is a brand fully owned by Kongsberg Maritime. The advanced technology in the Simrad sonars has transformed how we assess marine ecosystems and the world of fishing itself. With the constant development of sonars, echo sounders and catch monitoring instruments, they continue to forge an unprecedented path.

Watch how a Simrad sonar works on this link.