Pseudodiaptomus marinus Sato, 1913 in the Black Sea: morphology, genetic analysis, and variability in seasonal and interannual abundance

Abstract

Calanoid copepod Peudodiaptomus marinus Sato, 1913 was first recorded in Sevastopol Bay in the northern Black Sea in September 2016. We performed regular observations of this new invasive species between October 2016 and December 2018. We conducted bi-weekly plankton sampling at three stations located within or adjacent to Sevastopol Bay. This is the first paper to combine (i) a detailed morphological study, (ii) molecular genetic analysis, and (iii) an investigation of P. marinus seasonal dynamics and interannual abundance variability in the coastal Black Sea. Our morphological research showed similarities between Pseudodiaptomus specimens and existing P. marinus illustrations and descriptions. Our morphological analysis results were confirmed using molecular genetic studies. Based on the genetic variability of ITS2 and cytb, we found that all investigated specimens from Sevastopol Bay belonged to P. marinus. Investigations of P. marinus seasonal and interannual abundance variability showed the same seasonal patterns throughout the studied period, with a higher seasonal abundance from October to November and one pronounced density peak in autumn. The highest abundances (2,000 ind m–3 at the mouth of the bay and more than 5,000 ind m–3at its centre) were recorded in November 2018. In the samples, we found adults of both sexes, including ovigerous females, copepodites I–V, and nauplii, suggesting that the species reproduce in Sevastopol Bay. Our research indicated that P. marinus is a new non-indigenous species (NIS) in the Black Sea, and we will discuss a possible vector of its introduction into this basin.

Response of the Black Sea Zooplankton to the Marine Heat Wave 2010: Case of the Sevastopol Bay

“…The number of alien species and their abundance has increased in the Black Sea in recent decades. In addition to the described above A. tonsa and O. davisae, a new non-indigenous copepod P. marinus was reported in Sevastopol Bay in September 2016 [16,50]. All these new species are members of the warm-water mesozooplankton assemblage.…”

“…This redundancy should compensate for the loss of ecosystem functions of the Mediterranean zooplankton communities caused by climate change [14]. In the Black Sea, there are currently 12 species of marine planktonic copepods, three of which are invasive, namely Acartia tonsa, Oithona davisae, and Pseudadiaptomus marinus [15,16]. In this regard, changes in environment caused by climate impact or anthropogenic pressure lead to noticeable effects in the zooplankton community and the ecosystem of the Black Sea as a whole.…”