The cessation of stocking of the Vistula Lagoon with eels by Poland in the period from 1995 to 2004, and the ongoing depression of the eel population, led to a decrease in eel catches in both parts of the bay to 4–5 tons / year by the end of the first, most of the second decade of the 21st century. The tendency of eel population decrease was even more pronounced in the Curonian Lagoon, which has never been stocked with eel in historical retrospective. Eel catches in the Russian part of the bay fell from 150 tons in 1970 to 3-4 tons by the 1990s. and less than 1 ton in the present century. Stocking pasture reservoirs with young eels is a way not only to preserve eel stocks, but also to reasonably increase catches. In solving this problem, the question of the value of the commercial return coefficient becomes.