Turkish Journal of Fisheries and Aquatic Sciences
2016, Vol 16, Num, 1 (Pages: 077-090)
Adaptive Strategy of Thermophilic Oithona davisae in the Cold Black Sea Environment
2 Dokuz Eylul University, Institute of Marine Sciences and Technology, Izmir, Turkey DOI : 10.4194/1303-2712-v16_1_09 Viewed : 8169 - Downloaded : 4545 Annual dynamics of abundance and gender composition, seasonal variations in reproduction, respiration rate and locomotor activity of the new invasive cyclopoid species Oithona davisae were investigated in Sevastopol Bay (Black Sea) from January 2013 till July 2014. The abundance of O. davisae in Sevastopol Bay was highest in September – November at 15 – 23 ºC and decreased dramatically in winter – spring period at a temperature equal or less than 8ºC. From the end of February (8 ºC) till the middle of May (17.5 ºC) the population of O. davisae was represented only by adult females. Copepodites were observed first only when the water temperature increased to 17.5 ºC, and males appeared only in late May at 22 ºC. The revealed seasonal trends in copepod abundance and reproduction from field and experimental data suggest that winter population of O. davisae survives the cold season in the Black Sea at the stage of fertilized females which give the birth to the next generation in favorable spring conditions. To save energy resources, overwintering females have significantly lower temperature-related weight-specific respiration rate and moving activity than females from summer population. Such unique adaptation strategy facilitated the invasion and successful development of this thermophilic species in the cold Black Sea environment. Keywords : Oithona davisae; adaptive strategy; population dynamics; respiration; locomotion, Black Sea