Abstract

Three groups of mollusks of the triploid Pacific oyster Crassostrea gigas differing in morphometric parameters—fast-growing (FG) with a shell height of over 40 mm; medium-growing (MG), 15 mm < H < 40 mm; and slow-growing (SG), H < 15 mm—have been studied from the Donuzlav estuary (Black Sea). Stable differences have been revealed in the growth rates of juveniles of the same age. Mollusks of the FG group are dominant in weight gain and linear dimensions throughout the study. The average daily increase in the shell height of the studied mollusks ranges from 0.1 to 0.35 mm/day, with maximum values in June and September. The weight increases with different rates: on average, 0.051 g/day in the SG groups, 0.168 g/day in the MG group, and 0.287 g/day in the FG group. The peaks of this parameter have been recorded in August and September, reaching 0.12, 0.26, and 0.43 g/day, respectively. The shell height of slow-growing polyploid oysters has a negative allometry (b = 2.17), while the other two groups are characterized by a clear positive allometry (b = 3.23 for MG and 3.80 for FG); i.e., the increase in weight is faster than the linear growth in juveniles of the species. It has been suggested that polyploidy (triploidy) determines the differences in the growth rates of the same-aged mollusks. The allometry index b can be used to identify growth features at the early stages of oyster development.

中文翻译：

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三倍体牡蛎幼体生长率的稳定差异

摘要

三倍体太平洋牡蛎的三组软体动物Crassostrea gigas形态参数不同——快速生长（FG），壳高为超过40毫米；中等生长（MG），15毫米< H < 40毫米；和缓慢生长（SG），H b = 2.17），而其他两组则具有明显的正异速生长特征（ b = MG 3.23，FG 3.80）；即，体重的增加快于该物种幼体的线性增长。有人提出，多倍体（三倍体）决定了同龄软体动物生长速度的差异。异速生长指数b可用于识别牡蛎发育早期的生长特征。