人工培育拟穴青蟹大眼幼体及仔蟹相残机制研究

Cannibalism exists in the megalopae and juvenile of Scylla paramamosain, a economical important crab in China's south inshore sea area, both in natural environment and in the process of cultivation. Cannibalism significantly influences the population dynamics of Scylla paramamosain in the recruitment,closely related to the high mortality of megalopae in rearing, and restricts cultivation density. This project will (1) detect the cannibalism scale among megalopae and juvenile in rearing by measuring the stable isotope ratio of trophic level;(2) study how nutrition-biological energy accumulation and its relation with survival expectations; growth phase,resources availability,environmental physical-chemical factors,sediment and artifical refuges influence the cannibalism behavior among megalopae and juvenile through measuring biological energy, micro-video taping and extraneous tagging together with experimental ecology methods; and (3) explore the mechanism of cannibalism and its significance on adaptive value, which will improve survival rate in rearing Scylla paramamosain and will help develop technical facilities preventing cannibalism. The research findings are expected to contribute significantly to the knowledge of natural recruitment process and population fluctuation mechanism of Scylla paramamosain, accumulating data on population dynamics of the species in natural environment. Methodologically,the advanced methods used in this project are expected to result in more innovative methods in studying cannibalism behaviors of cruscateans.

拟穴青蟹（Scylla paramamosain）是我国南方近岸海区的重要经济蟹类，其大眼幼体和仔蟹在自然环境和人工培育条件下均可见相残行为。相残与育苗时大眼幼体高死亡率密切相关且制约养殖密度；对青蟹补充阶段的种群动力学影响显著。本项目拟以大眼幼体阶段为重点，采用稳定性同位素比营养级测定手段查明人工培育条件下青蟹大眼幼体和仔蟹相残的规模；以生物能值测定、显微摄像、体外标记结合实验生态等方法研究营养-生物能量积累及其相关存活期望值、发育阶段、资源可获得性、环境理化因子、底质及人工隐蔽物等对青蟹大眼幼体和仔蟹相残行为的影响，在此基础上探讨其相残的发生机制和适应性意义，为提高青蟹人工育苗成活率提供帮助指导，开发防止青蟹苗种相残的技术设施。研究结果对了解青蟹自然种群的补充过程与数量变动具有重要价值，可为青蟹自然种群动力学研究积累资料；在甲壳动物相残研究方法上有所拓展创新。

我国蟹类养殖产业规模大且发展前景良好。拟穴青蟹（Scylla paramamosain，以下简称青蟹）广布于我国南方近岸海区，对我国蟹类渔业和养殖业具有重要的价值。无论是在自然环境还是人工培育条件下，相残行为在青蟹中均常见。相残不仅被认为与青蟹幼体至后期幼体阶段的高死亡率有关，与自然条件下补充群体的种群衔接（Population connectivity）关系密切，也在现实中制约着蟹类养殖的集约化。本项目（人工培育拟穴青蟹大眼幼体及仔蟹相残机制研究）以青蟹大眼幼体和仔蟹在人工养殖条件下的相残为核心的研究目标，以稳定同位素法（Stable isotope analysis，以下简称SIA）为主要研究手段，辅以特定氨基酸分析（Compound specific isotopic analysis，以下简称CSIA）和红外摄影分析等研究手段，测定了青蟹大眼幼体和仔蟹在稳定同位素方面的基础数据；研究了近养殖条件下青蟹仔蟹与摄食有关的稳定同位素变化，并据此推断了同类在青蟹仔蟹摄食中的占比；研究了食物对蟹大眼幼体的张潮流输送（Flood tide transport，以下简称FTT）洄游的影响并探讨了其与种群动力学的关系。本研究的成果填补了我国蟹类FTT，SIA和CSIA研究方面的空白；为涉及蟹类的生理和生态研究积累了SIA及CSIA基础数据；探索了采用SIA方法研究蟹类相残行为的手段；探讨了开发防相残设施以缓解养殖条件下蟹类相残行为的研究思路。