Abstract Lutraria rhynchaena Jonas, 1844 is of great commercial interest, but its reserves have dramatically declined over recent decades. Therefore, there is an urgent need of scientific basis to propose effective fishery management measures and improve artificial aquaculture of the clam. In this study, we investigated the distribution and density of L. rhynchaena, sediment characteristics, and established the clam’s reproductive cycle through monthly observations from August 2017 to July 2018. The study results showed that distribution and density of clams are related to sediment types, and the sediment type of medium sand is likely the best benthic substrate for the clams. The spawning of clams occurred throughout the year with three spawning peaks in January, April and September. For the sustainable management of the clam resource in Cat Ba-Ha Long Bay, the fishery authorities can issue a ban on harvest of the clam in spawning peak months in January, April and September.

中文翻译：

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Lutraria rhynchaena Jonas, 1844 的分布和密度与沉积物有关，而在越南 Cat Ba-Ha Long 湾，繁殖显示每年出现多个峰值

摘要 Lutraria rhynchaena Jonas, 1844 具有巨大的商业价值，但近几十年来其储量急剧下降。因此，迫切需要科学依据来提出有效的渔业管理措施，改善蛤蜊的人工养殖。本研究通过2017年8月至2018年7月的月观测，调查了L. rhynchaena的分布和密度、沉积物特征，建立了蛤的繁殖周期。研究结果表明，蛤的分布和密度与沉积物类型有关，中砂的沉积物类型可能是蛤蜊的最佳底栖基质。蛤蜊全年产卵，1、4、9月有3个产卵高峰。