Pelagic Alpha - with double codend
The effectiveness of this trawl is caused by its net-part ability to direct the fish gathered in front of the trawl into the cod-end quickly and efficiently. This trawl has excellent results in cold waters of North Atlantic for Blue Whiting and Mackerel fishery.
The part of the trawl where fish motorial reorientation takes place is considered the trawl’s «critical zone». It is possible to set back the critical zone, but the construction of our trawl focuses on the horizontal opening of the net (belly) part by using double cod-end, rather than the prolonging/elongating of the belly part. Our idea follows principles used by twin-trawls which are known to expand the overall path/area of the trawl.
By dividing the trawl into two autonomous cod-ends, it helps to enlarge trawl’s horizontal opening while minimizing tightening force within the cod-ends. High openings of the trawl and the cod-ends, increase intake area and provide favorable conditions for fishing collection and distribution of fish into the cod-ends.
In double cod-end trawl, the speed of water inflow is the same as in single net (belly) and cod-end trawl. This leads to a far more balanced distribution of the fish into the cod-ends. Even fish distribution into the cod-ends leads to far higher fish quality-output. For example, each cod-end works approx. 5 meters apart from one another, thus, compared to a 200 tons catch into a single cod-end, the trawl separates apporx. 100 tons in each cod-end; the division of catch leads to less fish pressure and damage.
The traditional construction method is to improve the trawl’s «critical zone» by lengthening the net part of the trawl (trawl-В bellow). However, structural solutions of this kind lead to heavy material costs, production time, extra weight, repair times, increased dragging and overall trawl price.
Figure TRAWL A+C above demonstrate that both trawls have the same trawl length. However, the key advantage of the dual cod-end trawl is caused by the widening of the “guaranteed fishing area” leading to better water filtration and fish passage to cod-end.
Double cod-end trawl expands fishing-out territory by up to 20% while keeping the same trawl’s aggregate resistance. Real fishery hauling confirmed that double cod-end trawl catches are much better once compared to single cod-end trawls.
In short - Double cod-end trawl:
- Reduces gear costs
- Increases trawling speed
- Improves fish quality
