Acta Zoologica Bulgarica, vol.72, no.4, pp.517-524, 2020 (Journal Indexed in SCI Expanded)
Oithona davisae is one of the top 10 invaders in the ESENIAS area, widely distributed in the Black Sea.
According to published data, O. davisae has replaced the other cyclopoid copepod O. nana in the Black
Sea. The aim of the present study was to determine the population structure and abundance of O. davisae
in the coastal and offshore zones of the Southeast Black Sea Anatolian Continental Shelf Area in the
period from May 2015 to February 2016. Our results showed that the abundance of O. davisae was higher
in the coastal area compared to the offshore area. The mean abundance of O. davisae population changed
with season and it was the highest in November 2015 (7,344 ind. m-3). In contrast, the mean lowest
population abundance was estimated for coastal stations (170 ind. m-3) and for offshore stations (17 ind.
m-3) in February 2016 and May 2015, respectively. Therefore, it can be concluded that autumn is the most
productive period for O. davisae.