Norwegian shrimp fisherman Arild Karlsen has brought together the functions of the Notus Echo System and an SNTech CatchCam camera to improve the efficiency of his fishing operations and fish more precisely.
The Notus Echo uses sound to detect when fish and shellfish enter a trawl. As shrimp pass down the tunnel, they hit a grid and this generates an audible signal that is then transmitted to the wheelhouse.
More pings indicates more shrimp heading for the codend, and tells the skipper exactly when his gear is where it needs to be.
This also makes it possible to identify hotspots – and this is also where the CatchCam plays a part. Arild Karlsen found that it was a challenge to interpret signals in his mixed shrimp and whitefish fishery. The problem was knowing if fish or shrimp were hitting the sounding grid, especially if finfish were hitting it repeatedly.
By adding a CatchCam, mounted inside the extension of the trawl, he has been able to review footage of each tow and compare signals against underwater activity.
The CatchCam footage showed him that shrimp were banking up at the side of the grid and not hitting it properly, while finfish were generating false signals as they swam ahead of the grid, repeatedly falling back against it.
Comparing the Notus data against the visual evidence from the CatchCam has enabled him to adjust the Notus system to reduce contact with whitefish and to prevent the shrimp from banking up.
‘CatchCam was really helpful in making sense of the Echo system. It also helped with understanding the behaviour of the catch in the net and this information can be used to avoid unwanted bycatch. Without combining the two technologies I think we would still be guessing what is going on down there,’ Arild Karlsen said.
