Distribution and population characteristics of Mytilus edulis L. in the Seldyanaya, Kruglaya and Levaya bays the Chupa inlet, White Sea

The results of researching the structure of Mytilus edulis L. settlements and the growth rate of mollusks on the littoral of the Kruglaya, Sel'dyanaya and Levaya Bays of the Chupa Inlet, the White Sea in summer 2014-2015 have been presented; the spatial distribution, abundance indices, size-weight and age structure have been analyzed. Mussels form the huge aggregations on the middle and lover intertidal zone due to the nature of the bay bed represented by the stone-boulder belt and providing the mussel with large attachment surface. The increase in the abundance of mussels is observed simultaneously in two directions: from the upper horizon of the littoral to the lower one and from the mouth of the bay to its opposite part. In 2014, the highest mussel abundance was registered in the Kruglaya Bay, in 2015 - in the Levaya Bay. Molluscs of this species form aggregations with high biomass and density on the lower horizon of the littoral, which is associated with increased water exchange due to tidal currents that provide mussels with food. Mussels characterized by the largest size-weight parameters have been found in the Sel'dyanaya Bay. Mussels of 3-6 years dominated in the Kruglaya and Sel'dyanaya Bays in 2015. The mussels of 0-2 years dominated in the Levaya Bay the same year; the intensive subsidence of juveniles in the period under study has been observed. The highest growth rate has been observed for mussels inhabiting the Levaya Bay.