Madsen Nina A H, Aarsæther Karl G, Herrmann Bent
SINTEF Fisheries and Aquaculture, Hirtshals, Denmark.
SINTEF Fisheries and Aquaculture, Trondheim, Norway.
PLoS One. 2017 Aug 3;12(8):e0182609. doi: 10.1371/journal.pone.0182609. eCollection 2017.
Demersal Seining is an active fishing method applying two long seine ropes and a seine net. Demersal seining relies on fish responding to the seine rope as it moves during the fishing process. The seine ropes and net are deployed in a specific pattern encircling an area on the seabed. In some variants of demersal seining the haul-in procedure includes a towing phase where the fishing vessel moves forward before starting to winch in the seine ropes. The initial seine rope encircled area, the gradual change in it during the haul-in process and the fish's reaction to the moving seine ropes play an important role in the catch performance of demersal seine fishing. The current study investigates this subject by applying computer simulation models for demersal seine fishing. The demersal seine fishing is dynamic in nature and therefore a dynamic model, SeineSolver is applied for simulating the physical behaviour of the seine ropes during the fishing process. Information about the seine rope behaviour is used as input to another simulation tool, SeineFish that predicts the catch performance of the demersal seine fishing process. SeineFish implements a simple model for how fish at the seabed reacts to an approaching seine rope. Here, the SeineSolver and SeineFish tools are applied to investigate catching performance for a Norwegian demersal seine fishery targeting cod (Gadus morhua) in the coastal zone. The effect of seine rope layout pattern and the duration of the towing phase are investigated. Among the four different layout patterns investigated, the square layout pattern was predicted to perform best; catching 69%-86% more fish than would be obtained with the rectangular layout pattern. Inclusion of a towing phase in the fishing process was found to increase the catch performance for all layout patterns. For the square layout pattern, inclusion of a towing phase of 15 or 35 minutes increased the catch performance by respectively 37% and 48% compared to fishing without a towing phase. These results highlights the importance of the selected seine rope layout pattern and the duration of the towing phase when fishermen try to maximize the catch performance of their fishery. To our knowledge this is the first time the combination of models for the physical behaviour of seine ropes and for fish behaviour in response to seine rope movements have been applied to predict catch performance for demersal seining.
底拖网捕捞是一种使用两根长拖网绳和一张拖网的主动捕鱼方法。底拖网捕捞依赖于鱼类在捕鱼过程中对拖网绳移动的反应。拖网绳和网以特定模式部署，环绕海床上的一个区域。在底拖网捕捞的一些变体中，收网过程包括一个拖曳阶段，即渔船在开始绞收拖网绳之前向前移动。最初拖网绳环绕的区域、收网过程中该区域的逐渐变化以及鱼类对移动拖网绳的反应，对底拖网捕鱼的渔获性能起着重要作用。当前的研究通过应用底拖网捕鱼的计算机模拟模型来调查这个问题。底拖网捕鱼本质上是动态的，因此应用了一个动态模型SeineSolver来模拟捕鱼过程中拖网绳的物理行为。关于拖网绳行为的信息被用作另一个模拟工具SeineFish的输入，该工具预测底拖网捕鱼过程的渔获性能。SeineFish实现了一个关于海底鱼类如何对接近的拖网绳做出反应的简单模型。在此，应用SeineSolver和SeineFish工具来调查针对挪威沿海地区鳕鱼（大西洋鳕）的底拖网渔业的捕捞性能。研究了拖网绳布局模式和拖曳阶段持续时间的影响。在所研究的四种不同布局模式中，方形布局模式预计表现最佳；比矩形布局模式多捕获69% - 86%的鱼。发现在捕鱼过程中加入拖曳阶段会提高所有布局模式的渔获性能。对于方形布局模式，与没有拖曳阶段的捕鱼相比，加入15分钟或35分钟的拖曳阶段分别使渔获性能提高了37%和48%。这些结果突出了在渔民试图使渔业的渔获性能最大化时，所选拖网绳布局模式和拖曳阶段持续时间的重要性。据我们所知，这是首次将拖网绳物理行为模型和鱼类对拖网绳移动反应的行为模型结合起来用于预测底拖网捕捞的渔获性能。
