The copepods
selected the negative feeding mechanism at a low concentration
of food, whereas the positive feeding mechanism was adopted as
the density of food exceeded a critical value (Kleppel et al.,
1996). Grazing activities of zooplankton are also impacted by other
factors, such as temperature (Huntley and Lopez, 1992) and illumination.
Wang and Conover (1986) reported that the feeding intensity
of copepods at night was higher than that in day-time