Production and biological characteristics and genotoxic status of clam <i>Corbicula japonica</i> (Bivalvia, Corbiculidae) in the estuary of Avvakumovka River (Olga Bay, northwestern Japan Sea)
2016
Evgeny V. Kolpakov | Nikolay V. Kolpakov | Valentina V. Slobodskova
In the mesohaline estuary of the Avvakumovka River (43°42’ N), the clam Corbicula japonica inhabits sand and silt-sandy grounds on the depths > 0.5 m in the main channel and tributaries from the mouth to 5 km upstream. The highest density (up to 175 ind./m2, 3882 g/m2) is observed in the mouths of tributaries with low velocity of the flow. Settlements in different parts of estuary differ by abundance of C. japonica , its size-age structure, and growth rates. The maximum observed shell size was 53 mm, the maximum weight of mollusk - 43 g, the maximum age - 13 years. The growth rate variability within the estuary is comparable with its latitudinal variation. The clam has the maximal linear increment of shell length in the first year of its life and the maximal weight increment - in the age of 5-7 years. It reaches the commercial size (shell length 20 mm) in 3-4 years old. The annual secondary production of C. japonica does not exceed 17.8 gС/m2, with P/B-ratio 0.37. Its annual consumption exceeds its biomass in 2.0-2.4 times. Corbicula japonica in the Avvakumovka River is practically unaffected by genotoxic influence; the estuary is defined as a clean, low-polluted area.
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