Reproduction and Recruitment of the Intertidal Clam Darina solenoides (Bivalvia: Mactridae) in Patagonian Sandy Shores, Argentina
Reproduction and Recruitment of the Intertidal Clam Darina solenoides (Bivalvia: Mactridae) in Patagonian Sandy Shores, Argentina
复制标题
阿根廷巴塔哥尼亚沙滩潮间带蛤蜊（双壳纲：Mactridae）的繁殖和招募
作者：
M. López;Damián G. Gil;M. Kroeck;E. Morsan
摘要珊瑚(Darina solenodes，P.P.King，1832)是南美洲南部沙质海岸的一种资源丰富的文蛤。它作为包括迁徙海鸟在内的海洋捕食者的主要食物来源，具有重要的生态作用，是寄生生活史中的中间宿主。在阿根廷巴塔哥尼亚中部，我们描述了与环境因素有关的金龟子的繁殖周期和招募。连续两年(2016-2017；n=1,315)对采自圣豪格湾(SJG)两个沙岸的文蛤进行了性腺发育阶段的组织学分析和定量指标如条件指数(CI)、卵母细胞密度和相对卵母细胞面积(ROA)的检查。招聘模式是在单一地点进行的。壳长25.2~42.8 mm，性别比1：1差异不显著。被吸虫完全或部分去势的文蛤比例较低(5%)。发现了明显的年度繁殖周期，并具有性别、年份和地点高度同步的特点。戈尼亚的增殖持续到较冷的月份，卵黄发生主要发生在春季海水温度升高和主要浮游植物水华之后不久。卵母细胞的最大发育期(平均直径32.1±12.9微米)出现在夏季，雌雄均可产卵。夏季的沉降量也是最高的(平均值=162.8±47.1ind.m-2)，并与第二次浮游植物水华相吻合，这可能有利于幼体的发育和随后的早期补充。这是第一次对西南大西洋的猕猴双壳类进行繁殖研究，为巴塔哥尼亚沙岸这一关键物种的种群动态提供了有用的信息。
ABSTRACT Darina solenoides (P. P. King, 1832) is an abundant clam of sandy shores of southern South America. It has an essential ecologic role as a main food source for marine predators, including migratory seabirds, and is an intermediate host in parasitic life cycles. We describe the reproductive cycle and recruitment of D. solenoides in relation to environmental factors in central Patagonia, Argentina. Histological analysis of gonadal stages and quantitative indicators such as the condition index (CI), oocyte density and relative oocyte area (ROA) were examined monthly for two years (2016–2017; n = 1,315) from clams collected from two sandy shores of the San Jorge Gulf (SJG). Recruitment pattern was followed at a single site. The shell lengths ranged between 25.2 and 42.8 mm and the sex ratio did not differ significantly from 1:1. The proportion of clams showing total or partial castration by digenean trematodes was low (< 5%). A clear annual reproductive cycle was found and was characterized by high synchrony between sexes, years and sites. Proliferation of gonia extended throughout the colder months and vitellogenesis occurred mainly during the spring increase of seawater temperature and shortly after the major phytoplankton bloom. Maximum development of oocytes (mean diameter, 32.1 ± 12.9 µm) and presumed spawning by both males and females occurred during the austral summer. Settlement was also highest (mean = 162.8 ± 47.1 ind.m-2) during summer and was coincident with a second phytoplankton bloom that might favour larval development and subsequent early recruitment. This is the first reproductive study of a mactrid bivalve from the southwest Atlantic Ocean and provides useful information on the population dynamics of this key species from Patagonian sandy shores.