The state of benthic and planktonic invasive species in adjacent to St. Petersburg waters of the Gulf of Finland in 2018 as against the data for 2014

In 2018, a total of 45–57 zooplankton and 23–81 benthos taxa, as well as 0–6 alien zooplankton and 3–7 invasive zoobenthos species were found in different parts of the water area of the Gulf of Finland adjacent to St. Petersburg. From 2014 to 2018, aboriginal zooplankton and zoobenthos communities in the studied area remained relatively unchanged, while the populations of invasive species changed significantly. The range of some alien planktonic species extended to the east, i.e. to the Neva Bay, which could be due to their transfer from the adjacent areas of the Gulf of Finland. As compared to 2014, in 2018, a smaller number of invasive species in zoobenthos (only 10 species versus 14), as well as a significant reduction in the range or abundance of some invasive benthic species were recorded.