Modulation of digestive physiology and biochemistry in Mytilus californianus in response to feeding level acclimation and microhabitat

The intertidal mussel Mytilus californianus is a critical foundation species that is exposed to fluctuations in the environment along tidal and wave-exposure gradients. We investigated feeding and digestion in mussels under laboratory conditions and across environmental gradients in the field. We assessed whether mussels adopt a rate-maximization (higher ingestion and lower assimilation efficiency) or a yield-maximization acquisition strategy (lower ingestion and higher assimilation) under laboratory conditions by measuring feeding physiology and digestive enzyme activities. We used digestive enzyme activity to define resource acquisition strategies in laboratory studies, then measured digestive enzyme activities in three microhabitats at the extreme ends of the tidal and wave exposure gradients within a stretch of shore (