Seasonal variations in biochemical composition of mytilus edulis with reference to energy metabolism and gametogenesis

Abstract

1. 1. Seasonal changes in biochemical composition in relation to energy metabolism and to gametogenesis were studied in Mytilus edulis for nearly one and a half year.

2. 2. During the whole experimental period animals were selected from samples of the same musselbed in the Dutch Wadden Sea at intervals of about three weeks.

3. 3. The biochemical composition of total tissues and different organs was analyzed. In growing mussels a gradual increase of protein, glycogen and lipid contents was observed from spring to autumn. From November to next April the protein and glycogen content declined, whereas the lipid content remained rather constant until spawning. The observed changes are discussed in relation to environmental parameters as temperature, salinity and nutrient levels, as well as to energy production and gametogenesis.

4. 4. Hardly no seasonal variations were found in the total free amino acid concentrations from both the total tissues and different organs. However, the individual amino acids showed clear seasonal changes in all tissues investigated. The greatest fluctuations were found for taurine and glycine. These amino acids showed an inverse relation to each other.

5. 5. Seasonal changes in the accumulation of end products of anaerobic metabolism and in the composition of the free amino acid pool were found in groups of mussels exposed to air for 48 h. The observed variations in propionate and alanine accumulation as well as other compiunds involved in anaerobic metabolism are discussed in relation to temperature and salinity.