Seasonal cycle of zooplankton abundance and biomass in Hamsilos Bay, Sinop, Southern Black Sea, Turkey

ABSTRACT

In this investigation, zooplankton was studied between July 2015 and June 2016 in Hamsilos Bay to examine spatial and temporal variations in abundance, biomass and taxonomic composition. The recorded mean zooplankton abundance and biomass were 3770.35 ind. m⁻³ and 25.06 mg m⁻³ in the inner station, 3928.11 ind. m⁻³ and 28.19 mg m⁻³ in the middle station and 3948.22 ind. m⁻³ and 28.74 mg m⁻³ in the outer station, respectively. The high abundance and biomass values observed in September 2015 were attributed to Oithona davisae (4575 ind. m⁻³ at the inner station) and Penilia avirostris (33.4 mg m⁻³ at the outer station), respectively. Copepoda was the most abundant during the entire period of the survey. In terms of abundance and biomass, Copepoda was followed by meroplankton and Cladocera. Most species within the zooplankton community exhibited evident seasonality throughout the year in Hamsilos Bay. This was particularly apparent for O. davisae, Centropages ponticus, Cladocera and meroplankton, which were abundant in summer–autumn, and for Pseudocalanus elongatus, which was more abundant during winter and spring. It has been determined that O. davisae, which is a non-indigenous cyclopoid copepod species of the Black Sea, has successfully inhabited southern Black Sea and has established a permanent population in this area.

KEYWORDS:

• Zooplankton
• abundance
• biomass
• Turkey
• Black Sea

Acknowledgements

This work was supported by Sinop University for Scientific Research Project (SÜF-1901-14-04). I would like to thank Dr Izzet Noyan Yılmaz and Dr Pınar Gürbüzer for assistance with statistical analysis and valuable comments, Mrs Zeynep Bozdoğan (Hasançavuşoğlu) for chlorophyll-a data analyses, Dr Yakup Erdem for drawing the station map and special thanks the staff of the Zıpkın for their assistance in the field study. I would also like to thank referees and editor Bronwyn W. Williams for valuable comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This work was supported by the Sinop University for Scientific Research Project: [Grant Number SÜF-1901-14-04].