The use of side-scan sonar to combat fish poaching is considered. Illegal extraction of aquatic biological resources poses a serious threat to the economic and environmental security of Russia. The main fishing tool for poachers is a fishing net, which is located in the water column. Therefore, it is very difficult to detect it visually from a helicopter or boat. At the same time, the fishing net can be easily found using sonar systems. In 2017, the employees of the Southern Federal Uni-versity and LLC «NOLACS» carried out experimental studies in the water area of the Taganrog Bay, confirming this as-sumption. A typical scheme of active sonar is presented and described. The principles of the active sonar operation are explained. The principle of operation of side-scan sonar is described. The diagram is given and the principle of obtaining an acoustic image by side-scan sonar is described. The scheme is given and the methods and conditions of research are described. The main characteristics of the used side-scan sonar are given. Several acoustic images of fishing nets are pre-sented as results. Equipping fish protection vessels and boats of border guards with side-scan sonars will allow the em-ployees of these departments to timely detect and eliminate fishing nets. The cost of purchasing, installing and maintain-ing sonars is significantly less than the damage caused by poachers.

Authors: A. P. Voloshchenko

Direction: Physics

Keywords: Active sonar, side-scan, acoustic wave, beam width, sonogram, acoustic shadow, echo pulse

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