In situ mussel feeding behavior in relation to multiple environmental factors: Regulation through food concentration and tidal conditions

Feeding behavior of mussels (Mytilus edulis) was measured in situ using a video camera and expressed as the mean percentage of valve gape aperture (VA), concomitant with environmental and biological parameters over two tidal cycles. Mussel feeding behavior and the physical parameters responded to three primary tidal components, of which semidiurnal was dominant (12.42 h).

VA was synchronized with chlorophyll a (Chl a) concentration (proxy for food) with a strong positive correlation (r = 0.72, p < 0.001). Chl a and suspended particulate matter (SPM) were dependent on tidal advection. The combination of the reconstructed tidal constituents derived from harmonic analysis were used to successfully model mussel feeding behavior (r = 0.90, p < 0.001).

In this concentration range ($0.6 to 2.5 \mu g L^{-1}$), Chl a, measured at 1 m above the mussel bed, regulates mussel feeding behavior irrespective of the presence of predators, changes in SPM, or flow velocity.