Potential of commercial echosounders utilization for fish stock assessment
Relatively low-cost commercial echosounders became wide-spread at present. This article is a review of some methodical aspects of commercial echosounders utilization in fisheries researches applying the method of echo-counting. Most of modern commercial echosounders have the fish-ID function, which ease echo-counting process for an inexperienced operator <i>prima facie</i>. Unavoidable mistakes of fish-ID function may lead to both overestimation and underestimation of fish density on survey area. However, some of these mistakes may be corrected if operator possesses certain experience. Hydroacoustic surveys on Rybinsk reservoir performed using scientific and commercial echosounders showed inessential differences between values of fish density obtained, if some specific requirements were followed.