Cohort life tables for a population of the soft-shell clam, Mya arenaria L., in the White Sea

Autor: Nikolay V. Maximovich, Alexandra V. Gerasimova, Nadezhda A. Filippova
Rok vydání: 2014
Předmět:
Zdroj: Helgoland Marine Research. 69:147-158
ISSN: 1438-3888
1438-387X
Popis: The Mya arenaria generation in the White Sea was observed for almost the whole life cycle (around 25 years). Using the data on this generation dynamics, the cohort life table was built. The main purpose of the research is analysis of age-specific mortality in this soft-shell clam population. The mortality rate was found to change more than tenfold throughout the study period. No regular changes in its value were observed. Periods of low mortality alternated with periods of much higher mortality. Several reasons for the increase in M. arenaria mortality rate during its life cycle are proposed: (a) living in the surface sediment layer at early stages of life cycle (unstable environment, high mortality of non-viable clams, predator impact); (b) intense intraspecific relationships in dense aggregations of young clams; (c) increased intraspecific competition during periods of the rapid individual growth; (d) ageing (clam mortality increases with older age—achievement of an average and a maximum lifespan).
Databáze: OpenAIRE
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