Physiological-Responses Of Mytilus-Edulis L To Parasitic Infestation By Mytilicola-Intestinalis

Various levels of infestation by Mytilicola had no effect on the rates of oxygen consumption by Mytilus edulis in laboratory experiments. However, high levels of infestation (> 10 parasites per mussel) caused a depression in the feeding rate of the host at high temperatures (22° or 23° C) and low ration (maintenance or sub-maintenance). This depression of feeding resulted in a decline in the scope for growth, which would result in time in a decline in the “condition” of the host. It is concluded that similar effects may occur in the field when large numbers of small parasites are present at a time of high metabolic demand and low food availability.

Physiological Ecology Of 2 Populations Of Mytilus-Edulis-L

Seasonal cycles in the rates of oxygen consumption, feeding, absorption efficiency and ammonia-nitrogen excretion in two populations of Mytilus edulis were measured in the field under ambient conditions and related to body size, the gametogenic cycle, the concentration of suspended particulate matter in the water and temperature. Relationships between the various physiological variables are also considered and protein and energy budgets estimated. Both the “scope for growth” and the “relative maintenance cost” were seasonally variable, demonstrating a minimum capacity for growth in the winter and a maximum capacity in the summer. In one population subjected to abnormally high temperatures in the winter the scope for growth was negative for four or five months between January and May. These population differences are discussed and the potential for using physiological integrations in intra-specific comparisons of fitness is identified.