Abstract
AbstractMonthly samples of Abra ovata were collected during February 1983‐January 1984 in the Evros Delta (N. Aegean Sea). Population density (mean annual value = 2407.5 ind · m−2) was characterized by seasonal variation. An analysis of the length frequency distributions shows that one annual recruitment of juveniles (> 2 mm) occurred in October‐January; and also that, throughout the year, two age groups existed in the population. One growth ring was formed on the shells of the oldest age group during July‐August.Mean growth in shell length can be described by Bertalanffy function. A positive correlation existed between shell length and decalcified dry weight.Secondary production in A. ovata, calculated by the instantaneous growth method, showed a mean biomass of 29.221 g dry weight m−2yr−1, a productivity of 17.086 g dry weight m−2yr−1 and an annual turnover ratio of 0.59.
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