Ecology of Margaritifera margaritifera (Bivalvia, Margaritiferidae) in the River Kamennaya, White Sea Basin, Russia

Abstract

The conditions for cohabitation of juvenile Salmo salar and Margaritifera margaritifera in the River Kamennaya (River Kem catchment, White Sea drainage basin, Russia) were studied. The M. margaritifera population in the River Kamennaya contains about 1000 specimens. The only intermediate host capable of sustaining the existence of this rare North European mussel is the juvenile S. salar. In this study, we investigated a set of parameters and processes to get a more comprehensive insight into the ecology of the M. margaritifera. One of such parameters is the individual linear growth, which was investigated in freshwater mussels from the River Kamennaya. Growth deceleration coefficients varied widely and differed significantly among specimens. The population-averaged coefficient of growth deceleration was 0.076. The growth of mussels in the River Kamennaya involves three regular biorhythms with the following periods: 11.5, 6.4 and 4.0 years. The biorhythm periods were roughly constant both through an individual's ontogeny and among different individuals. A comparison of our results with data on other M. margaritifera populations in the Republic of Karelia and the Murmansk Region reveals a reliable (p < 0.01) negative correlation between growth deceleration coefficients and mean annual temperature in the M. margaritifera habitat. The abundance, spatial distribution and age structure of juvenile S. salar and M. margaritifera are presented. The rates of glochidial infection in S. salar juveniles at different ages were estimated. The developmental stages and the status of glochidia encysted on juvenile S. salar gills were observed and described using histological methods. The results of this study will be used to suggest activities and measures aimed to preserve populations of M. margaritifera and S. salar in the River Kamennaya, primarily to promote juvenile S. salar numbers and M. margaritifera settlement in rapids with a high density of young individuals.

Keywords

• atlantic salmon
• endangered species conservation
• freshwater pearl mussel
• glochidia
• growth
• infection
• salmo salar