Population structure, condition index and age structure of the Mediterranean carpet shell clams Donax semistriatus and Donax trunculus (Mollusca: Bivalvia) in Idku, Egypt
Population structure, condition index and age structure of the Mediterranean carpet shell clams Donax semistriatus and Donax trunculus (Mollusca: Bivalvia) in Idku, Egypt
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埃及伊德库地中海地毯蛤 Donax semistratus 和 Donax trunculus（软体动物：双壳纲）的种群结构、状况指数和年龄结构
DOI：
10.21608/ejabf.2014.2192
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发表时间：
2014
影响因子：
--
通讯作者：
Saad Z. Mohamed
中科院分区：
文献类型：
--
作者：
Rabab Alkaradawe;Z. Morsy;S. Mohammad;Saad Z. Mohamed
本研究调查了埃及最常见的双壳贝类物种的种群结构和外壳形态测量关系;半条纹唐鱼和截形唐鱼。从2008年11月到2010年5月，每月从埃及北部贝希拉省伊德库市地中海沿岸的两个地点收集蛤蜊。平静D的最主要的大小。semistriatus为12.1-16 mm的个体;躯干，大小级间距分别为18.1-22 mm和14.1-18 mm的动物分别占据了地点1和地点2。D. semistriatus每年有两次补充，而D. trunculus只记录了一个时期。壳长与各壳径、体重参数的关系总体上呈明显的负异速生长趋势。性腺重与壳长、干重与壳长的关系均为正异速生长。两种文蛤在2号地点的生长速率略高于1号地点。两种鱼的性腺指数与生殖活动基本一致。此外，本文还对消化腺和消化状态指标进行了讨论。用Bhattacharya的方法进行年龄测定表明，D. semistriatus和D. trunculus在这两个地点记录了三个年龄组。对这两种双壳类的生态学解释是明确的。
This study investigates the population structure and shell morphometric relationships for the most common bivalve species in Egypt; Donax semistriatus and Donax trunculus. The clams were monthly collected from November 2008 to May 2010 from two sites on the Mediterranean coast, Idku city, Behira governorate, North Egypt. The most dominate size of the calm D. semistriatus is the individuals with class intervals of 12.1-16 mm. For D. trunculus, animals with size class intervals of 18.1-22 mm and 14.1-18 mm dominated site 1 and site 2 respectively. The population of D. semistriatus showed two periods of recruitments each year whilest that of D. trunculus recorded one period only. The results also showed apparent general tendency toward negative allometry in most relationship between shell length and each of shell measurements and body weigh parameters. Positive allometric growth exhibited in gonad weight / shell length and dry weight/shell length relationships. The growth rate at site 2 slightly higher than that at site 1 for the two clams. Gonad indices of both species were more or less coincided with the reproductive activity. In addition, digestive gland and condition indices were also discussed in the present study. Age determination using Bhattacharya's method revealed that D. semistriatus and D. trunculus recorded three age groups at both sites. Several ecological explanations were formulated for the two bivalve species.