Cardiac activity and oxygen consumption of blue mussels (Mytilus edulis) from the White Sea in relation to body mass, ambient temperature and food availability

Abstract

It is generally suggested that cardiac activity in mytilids is positively correlated with their basic metabolism level, but studies of that connection are lacking. Moreover, there is a gap in our knowledge of the influence of food on heart rate (HR, min⁻¹) in blue mussels (Mytilus edulis L.). Consequently, the correlation between HR and standard respiration, body wet weight, and phytoplankton concentration in a suspended culture of blue mussels from the White Sea was examined. The measurements were carried out both under laboratory conditions and in situ during the harsh winter period when the mussel culture lines are suspended under thick ice cover. The relationship between HR and oxygen consumption (mg O₂ g wet weight⁻¹ h⁻¹) was reliably described by the power function. Under both laboratory and in situ conditions, both cardiac activity and oxygen consumption were correlated to wet weight. In March, all relationships were significantly different from those in late April. These differences are discussed with respect to the drastic increase in phytoplankton concentration. The relatively high HR activity (3–8 beats min⁻¹) at very low ambient temperatures (−1.8 to −0.6 °C) should be noted.