Models of operation processes of bottom trawl under complex impact of abiotic, biotic and anthropogenic factors

Abstract

In commercial fishing the bottom trawls are recognized as one of the most intensive tools for active use. Bottom trawls seriously impact the benthos in the fishing area. As a result of this impact, the suspended benthos forms extensive tail areas of sediments and dissolved nutrients. In addition, the movement of trawl doors on the ground, as well as the ground rope and cables increase the total resistance and wear of the bottom trawls. Consequently, these factors may cause the negative environmental effects, and lower the efficiency and safety of the bottom trawl system and its fishing operations, which can contribute to greater emissions of nitrogen oxides, sulfur oxides and greenhouse gases. At the initial stage of development of bottom trawl systems, the primary task is to draw up a list of operational requirements that the bottom trawl will satisfy. Generally, the list of these requirements includes functional requirements, i.e. a list of quantitative indicators of the fishing object to which the bottom trawl is directed, indicators of special fishing conditions and restrictions under which fishing is performed, indicators of environmental friendliness of fishing, energy costs, etc. Understanding these processes allows the development of performance requirements that bottom trawls can fully meet. Models of the operation processes of the bottom trawl complex have been developed, taking into account the complex influence of abiotic, biotic and anthropogenic factors, and the impact of the human factor on the control systems of the trawl complex. Within the framework of our research, a quantitative and a qualitative assessment of the physical impact of the above factors on the elements of bottom trawl systems used in the fishery.