The meristic (countable) characters, in particular, to the number of rays in the fins are main signs among the morphological criteria of the species in fish. This is one of the most stable and not subject to resizing signs of fish morphotype. Moreover, it is a clear taxonomic criterion. The aim of the work is to study the variability of the number of rays in the dorsal fin and specification of the dorsal fin formula of black scorpionfish from the coast of the North Caucasus and Crimean shore of Black Sea. In this article were studied 232 individuals of a black scorpionfish from six areas of the Black Sea located off the coast of the North Caucasus (Big Utrish, Magri, Loo, Adler) and Crimea (Sevastopol, Feodosiya). The number of rays in the dorsal fin of each fish was calculated, dividing them into hard (non-branching) and soft (branching). It was established that the total number of rays in the dorsal fin of black scorpionfish from the shores of North Caucasus and Crimea were 22.1±0.02, the number of hard (unbranched) rays were 12.0±0.01, soft (branched) were 10.1±0.03. All three indicators are characterized by a low degree of variation (coefficient of variation less than 10%). There are some statistically significantly differences in number of soft rays in the dorsal fin of fish from the shores of the North Caucasus and Crimea (10.1±0.03 and 10.0±0.04, respectively). There are some statistically significantly differences in total number of rays in the dorsal fin of fish the shores of the North Caucasus and Crimea (22.1±0.03 and 22.0±0.04, respectively). An analysis of our own materials revealed the existence of six possible variants of the formula for the dorsal fin of a black sorpionfish from shores of the North Caucasus and Crimea. There are D XI 10, D XI 11, D XII 9, D XII 10, D XII 11, D XIII 10. The variant of the dorsal fin formula D XII 10 was the most common both in the sample and in each of the considered water areas (on average 83,2%). The updated formula for the dorsal fin of the black scorpionfish from shores of the North Caucasus and Crimea has the following form: D (XI) XII (XIII) (9) 10 (11). The results are compared with other researchers. The reasons for the differences are analyzed.