Feeding rates of continually submerged Hydrobia ulvae vary during the daylight hours

Abstract

Feeding, as estimated by egestion rate, in coastal epibenthic mud snails Hydrobia ulvae living continually submerged in lagoon-like conditions varies significantly with time of day. Both in the field and in the laboratory, egestion rate is maximal around mid-day and minimal at twilight. This variation, here ranging in magnitude from mean lows of some nine faecal pellets h⁻¹ to highs of 34 h⁻¹, is consonant with likely rhythms of availability and productivity of their microphytobenthic food.