Fig 1.
Demersal seine fishing procedure (collection and closing phase) from top to bottom.
1: seine net. 2: seine rope. 3: fishing vessel. 4: fish collected ahead of seine net. The grey dots represent aggregations of fish at the seabed. In this case, the fish is being uniformly distributed. Seine net, fishing vessel and fish aggregations are scaled up compared to the length of the seine ropes for illustration purposes.
Fig 2.
Fish (grey ellipses) reaction to an approaching seine rope (green curve).
The zoomed picture on the right side illustrates that when the seine rope gets closer to the fish than the distance lmin it reacts by swimming the distance lmove further away from the seine rope in a direction perpendicular to the seine rope. The seine net, the fishing vessel and fish aggregations are scaled up compared to the length of the seine ropes for illustration purposes.
Fig 3.
The four different initial layout patterns simulated.
From left: rectangular, square, triangular and diamond. The seine net (grey triangle) and the fishing vessel (blue pentagon) are scaled up compared to the extent of the seine ropes for illustration purposes (screen dumps from simulations using SeineFish).
Fig 4.
Illustration of the fishing process (from left to right) for each of the three towing phase cases investigated.
From top: no towing, 15 minutes towing and 35 minutes towing. Here illustrated for the diamond shaped initial layout pattern. The seine net (grey triangle), the fishing vessel (blue pentagon) and thefish aggregations (grey dots) are scaled up compared to the length of the seine ropes (green curves) for illustration purposes (screen dumps from simulations using SeineFish).
Fig 5.
Illustration of the physical behaviour of the fishing gear during different steps of the fishing process for each of the 12 fishing cases investigated.
From top to bottom: no towing, 15 minutes towing, 35 minutes towing. From left to right: rectangular, square, triangular, diamond initial layout pattern. The seine net (grey triangle) and the fishing vessel (blue pentagon) are scaled up compared to the length of the seine ropes (green curves) for illustration purposes (screen dumps from simulations using SeineFish).
Fig 6.
Development in the number of fish encircled by the seine ropes on the seabed (fish count) during the fishing process for deployment of the four initial layout patterns investigated and for each towing phase scenarios.
Table 1.
Number of fish encircled during the fishing process.
Numbers in parenthesis are percentage increase compared to value after initial layout.
Fig 7.
Illustration of the development in the area encircled (green area) by the seine ropes on the seabed during the fishing process (from left to right) for the four layout patterns (from top to bottom).
Here illustrated for the 15 minutes towing phase. The seine net (grey triangle), the fishing vessel (blue pentagon) and the fish aggregations (grey dots) are scaled up compared to the length of the seine ropes (green curves) for illustration purposes (screen dumps from simulations using SeineFish).
Fig 8.
Development in the area encircled by the seine ropes on the seabed during the fishing process for the four initial layout patterns investigated and for each towing phase scenarios.
Fig 9.
Development in the entry width into the area encircled by the seine ropes on the seabed during the fishing process for the four initial layout patterns investigated and for each towing phase scenarios.