Maximova N.V., Sitnikova T.Ya., Mizandrontsev I.B. 2007. [The growth of endemic Baikalian snail Maackia herderiana (Lindholm, 1909) (Caenogastropoda: Baicaliidae)] // Invertebrate Zoology. Vol.4. No.1: 45–63 [in Russian, with English summary].
Limnological Institute SB RAS, Ulan-Batorskaya 3, Irkutsk 664033, Russia. E-mail: email@example.com
KEY WORDS: growth, snails.
ABSTRACT: The characteristics of growth as estimated with shell size and body mass changes in endemic Baikalian snail Maackia herderiana (Caenogastropoda: Baicaliidae) have been studied. It was shown that the snails grow during all their life. The growth rate of shell is not constant and depends on season and age. Body mass of the snail changes according to an equation: dM/dt = б(t)·M, where coefficient α depends on time t. Compared to other freshwater mollusks, the initial stage of mass growth in M. herderiana is much longer and takes up to half of the life span. The specific growth rate is the highest during the initial stages of development, with absolute growth rate higher during the maturation period. During the period of fast shell growth, increase in body mass is slow, but becomes rapid following the cessation of fast shell growth. The relative weight of soft body parts increases significantly with age: from 4% of the total weight in newly-hatched spat to about 30% in mature snails, which is approximately twice as low as in other palaearctic mollusks. During the first three years of life, shell length increases faster then width. Coefficients of allometric equation are not constant and with variable rates of increase in shell height and body mass.