Growth Biorhythms of the Freshwater Pearl Mussel Margaritifera margaritifera (Bivalvia,Margaritiferidae), Nemina River Population (Karelia)

Biology Bulletin - Individual linear growth was studied in 23 specimens of the freshwater pearl mussel Margaritifera margaritifera by measuring successive annual growth rings on the shell surface....     

Historical geography of pearl harvesting and current status of populations of freshwater pearl mussel Margaritifera margaritifera (L.) in the western part of Northern European Russia

This paper summarises data on the occurrence of freshwater pearl mussel Margaritifera margaritifera in the western part of Northern European Russia adjacent to White Sea, Barents Sea, Onega Lake and Ladoga Lake basins. Also, this article provides an overview of the literature-based data and archive materials on the history of pearl harvesting. We include a list of rivers of Northwestern Russia, where pearls were harvested during the period of the sixteenth to twentieth centuries. The pearl mussel populations at the present time exist in at least 24 water streams in Northwestern Russia. Many of these populations are in high abundance and are able to reproduce normally. Data on the status of populations are given in this paper. Data indicate that the pearl mussel population in Russia contains >143.5 million individuals, but this estimation is certainly undervalued. Timber floating (timber floating is the transport of timber on waterways), hydro-engineering construction, pollution of rivers by industrial wastes and introduction of alien species, as well as a reduction in host fish species numbers can all be cited as the main factors that transformed the ecosystems inhabited by pearl mussel of Northern Russia. In addition, methods used in the Russian Federation for decreasing the anthropogenic load on pearl mussel populations were considered.     

The rate of oxygen consumption during embryogenesis of Lymnaea stagnalis (Gastropoda)

We studied the rate of oxygen consumption by the Lymnaea stagnalis embryos. The rate of oxygen consumption increased consistently during embryogenesis. The volume specific rate of oxygen consumption increased initially from the early cleavage stages until the gastrula stage and then decreased gradually to the eclosion of snails. There are three periods in embryogenesis of L. stagnalis, which differ in the coefficients of allometric dependence between the rate of oxygen consumption and volume of embryos: (1) early embryogenesis, when the increase in the rate of oxygen consumption is not accompanied by the growth of volume of the embryos; (2) larval period (trochophore and veliger stages; exponential coefficient k = 0.514), and (3) postlarval period (exponential coefficient k = 0.206).     

Equations describing changes in weight and mass-specific rate of oxygen consumption in animals during postembryonic development

Equations describing growth and respiration rate of animals during postembryonic development have been derived on the basis of thermodynamics of linear irreversible processes. The conditions for equation application are specified as well as the conditions when growth equation can be reduced to the von Bertalanffy equation and when the relationship between the mass-specific rate of oxygen consumption and body weight becomes an allometric relationship.     

Respiration and heat production in the embryonic development of chickens

A marked increase in the rate of oxagen consumption and heat production, measured by the direct method, is observed in the chick embryogenesis. The intensity of respiration and heat production of the embryos decreases as the development proceeds. During development the data obtained by direct and indirect calorimetry diverge. This divergence, referred to as psi u-function, gradually decreases by the moment of hatching. Differences in the value of heat production and psi u-function were found in crosses of meat and egg directions, related to differences in the growth rate and productivity of adult fowl.     

Comparative analysis of the growth of <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> (Bivalvia) from different populations of Karelia and Kola Peninsula

Comparative analysis of individual linear growth of Margaritifera margaritifera populations from the Syuskyuyanioki, Nemina, Vuokinioki, Keret (Karelia), and Varzuga (Kola Peninsula) rivers has been performed. Data on the lengths of consecutive annual growth rings on the external shell surface have been obtained. The comparative analysis has been made of two coefficients of the united growth equation, one of which determines the initial growth rate; the other determines growth inhibition. Growth parameters are assumed to vary greatly within each population and differ significantly between different specimens. The values of the coefficients decrease with increasing geographical latitude of the habitat. It is shown that the population in the Syuskyuyanioki River is comparable with respect to the growth constant with the southernmost populations of rivers in Northern Spain.     

The growth and energy metabolism of <Emphasis Type="Italic">Lymnaea stagnalis</Emphasis> (Lymnaeidae,Gastropoda): I. Early postlarval period

The growth and the oxygen consumption rate of Lymnaea stagnalis were studied during the first ten weeks after hatching. It is shown that these processes are atypical during early ontogenesis in comparison with adult mollusks. The obtained data on linear (height of shell) and weight growth can be equally well approximated with the von Bertalanffy equation or exponential and power equations. Both linear and weight growth are characterized by an approximately constant specific rate associated with synchronous oscillations of a week period. The oscillations were observed also for the oxygen consumption rate, but of another period (about 2.6 weeks). On average the metabolic rate after the initial triple increase during the first three days remains stable. The power coefficient of the allometric dependence of the total weight on the shell height is significantly less than that of the adult.     

Biorhythms of <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> (Bivalvia,Margaritiferidae) Freshwater Pearl Mussel Growth: Population of Syuskyuyanioki River (Karelia)

It was demonstrated that individual linear growth of the Margaritifera margaritifera freshwater bivalve mollusk in Syuskyuyanioki River is accompanied by natural biorhythms. The periods of biorhythms, as well as growth retardation coefficients, vary widely and differ in different individuals. The periods of biorhythms in individual ontogenesis are approximately constant. Mean values of the growth retardation coefficients and periods do not depend on the biotope and are 0.114 ± 0.003 year^–1 and 3.88 ± 0.06 years, respectively. The possibility of thermodynamic nature of biorhythms is discussed.     

Irregularity of the linear growth of the <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> (Bivalvia: Margaritiferidae) population of the Nemina River,Karelia

The dependence of shell growth in length and height during ontogeny has been studied in the pearl mussel Margaritifera margaritifera inhabiting the Nemina River (basin of Lake Onega, Karelia). It has been shown that the population is heterogenous based on the height-to-length ratio. It has been found that during ontogeny M. margaritifera from the studied population undergoes a constant change in the relative growth of the shell leading to either lengthening or rounding of the shell.