Spatial and Seasonal Variation of the New Invader Oithona davisae (Ferrari F. D. Orsi, 1984) (Cyclopoida: Oithonidae) in the Southeast Black Sea

摘要

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.