All over the world hypersaline lake/lagoons are threatened by climate change. The marine Bakalskoye Lake (Ukraine) was studied in 2000-2012. The paper considers changing crustaceans within the context of the lagoon changes. A sharp drop of salinity occurred in 2004 due to a changed wind rose because the strong winds of Western direction began to dominate, and as a result, washing away of the spit began to be more intensive; and marine water inflow into the lake increased. The structure of primary productivity has changed completely; the total primary production decreased. A list of crustacean species found in the lake includes 19 species. In 2004 there was a change of the composition of crustaceans due to three factors - a change of salinity, an increase of erosion, and massive transport of marine organisms into the lake. Integral characteristics of zooplankton also significantly changed. Impact of climate change on crustaceans is not only direct, but through an extensive network of intermediate effects which are discussed. The study results are of more than local relevance; it has a general ecological importance because can help to better understand that the realizations of general climate change impacts on local level are diverse.