Peculiarities of population structure and biocenotic relationships of Rapana venosa (Gastropoda, Muricidae) in Donuslav bay of the Black Sea

Abstract

The Western Pacific gastropod Rapana venosa is classified as one of the 100 most dangerous invasive species of the Black and Mediterranean Seas. The species is recognized as a dangerous invader in a number of coastal waters on both sides of the Atlantic Ocean. This circumstance determines the relevance of the study of population characteristics and biocenotic relations of Rapa-whelk in the areas of invasion. A study of a previously unexplored population in the Donuzlav Bay (NW Crimea) of the Black Sea in 2020 showed that in the presence of an abundant and varied food base, R. venosa does not form mass clusters andconsequently does not significantly affect benthic biocenoses.This is also confirmed by the ratio of the biomass of the predatory mollusk and its prey.The average biomass of the Rapa whelk in the surveyed area was 3.8 g / m², and the average biomass of its food objects - Bivalvia - 620.8 g / m². The features of the population structure and biocenotic relationships of the Rapa whelk in the Donuzlav Bay are considered and discussedfor the first time. Direct underwater observations and indirect evidence indicate that the distribution of the invasive species R. venosa is controlled by aboriginal predators – crabs.The main species limiting the number of the Rapa whelk in the study area is the crabCarcinus aestuarii.

Keywords: biocenoses, algae, invasive species, crabs, molluscs. Predator - prey