Spanish trawler María dels Angels 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.
The 27m trawler targets deep water red prawns in depths up to 700m and lets out up to 2,200m of trawl wire. The bottom is very hilly with narrow canyons - 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 and also to enter small canyons, as this greatly increases catch.
The María dels Angels has a complete Notus Trawlmaster system onboard. Doorspread (distance between the doors), trawl wire lengths (distance from the vessel to EACH door), door angle (the inward/outward heel of the door while depths give the distance from the surface to the sensors), depth, headline height (the vertical opening of the net while trawl alignment is the distance from EACH door to the center of the headline), and trawl alignment are all monitored.
In the past, the María dels Angels would have taken the 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 0.5m.
Turing while the trawl is at 700m of depth can be difficult, but by using spread and trawl wire lengths, a turn can be completed in just 15 minutes (this would have previously taken 35-40 minutes). Often in a turn, the doors can be out of align by 100 meters. Notus claims that its system is the only one to use omnidirectional technology in its sensors so doorspread is still monitored with one door 100m behind the other.
In this deep water shrimp fishery 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, which has resulted in a doubling of catch rates at certain times.
