Over the last 20 years, a major goal of Notus has been to share knowledge between different fisheries. As such, this article focuses on the F/V María dels Angels from Barcelona, Spain.
This vessel has been using Notus’s trawl monitoring system over the last two years and has learned a lot about his gear and how to double catch rates in some areas. A video showing the Trawlmaster onboard can be found at
The María dels Angels is a 27 m trawler targeting deep water red prawns. The vessel fishes in depths up to 700 m and lets out up to 2200 meters of trawl wire. The bottom is very hilly with narrow canyons as can be seen in the aside graphic of the bottom. Trawling over such a bottom and at these depths can be difficult for any Captain. To be successful in this area, the Captain must have the ability to turn within 0.1 nm. Equally important, is the ability to enter small canyons, as this greatly increases catch.
The María dels Angels has a complete Notus Trawlmaster system onboard. The following parameters are monitored: doorspread, trawl wire lengths, door angle, depth, headline height and trawl alignment. Doorspread provides the distance between the doors. Trawl wire lengths are the distances from the vessel to EACH door. Door angles indicate the inward/outward heel of the door while depths give the distance from the surface to the sensors. Height is the vertical opening of the net while trawl alignment is the distance from EACH door to the center of the headline.
In the past, the María dels Angels would have taken their trawl wires to shore and measured EACH trawl wire every two months. Considering the long trawl wires, this would be an all-day task. This time consuming activity is eliminated with the Trawlmaster as trawl wire lengths are measured constantly throughout the tow with accuracy better than 0.5 m.
Turing while the trawl is at 700 m of depth can be difficult. Before Notus, a turn would have taken 35-40 minutes. By using spread and trawl wire lengths, a turn can be completed in just 15 minutes. Often in a turn, the doors can be out of align by 100 meters. Notus is the only system to use an omnidirectional technology in its sensors so doorspread is still monitored with one door 100 m behind the other. The above graphic shows a typical Trawlmaster screen when turning.
In this deep water shrimp fisher a large fraction of the shrimp are located in submarine canyons. With the Trawlmaster, the Captain is able to constantly adjust doorspread in order to fit the trawl into these small canyons. This has resulted in a doubling of catch rates at certain times.
A video showing the Trawlmaster onboard can be found here.
Notus Electronics Ltd. – FiskerForum.com
