Effect of food composition and temperature on in situ feeding rates of ctenophore invader Mnemiopsis leidyi A. Agassiz

Abstract

The feeding rates of ctenophore Mnemiopsis leidyi were estimated using the data of the abundance and food composition in the inshore waters of the northwestern Black Sea in 2009–2010. The clearance rate varied in regard to the different foods. The maximum rates were observed when M. leidyi consumed Bivalvia veligers (400 L ind.−1 day−1); the minimum rates were observed when it fed on Copepoda (35 L ind.−1 day−1). The feeding rate increased in accordance with the water temperature in the range from 13°C to 27°C, but dropped when the temperature was higher than 27–28°C. These data were used to calculate the predatory impact of the M. leidyi population on the different groups of its prey and on the zooplankton community in total. The predatory pressure on each prey group and on the zooplankton community was significantly lower for the period of 2009–2010 compared to the previous years. This indicated the decrease in the predatory pressure of the M. leidyi population on the zooplankton community.