【作者】 韩耀龙；

【导师】 李远友；

【作者基本信息】 汕头大学 ， 海洋生物学， 2011， 硕士

【摘要】 拟穴青蟹(Scylla paramamosain,简称青蟹)是我国东南沿海地区重要的海洋经济养殖蟹类,之前我国有关锯缘青蟹的研究报道实际上都应归为拟穴青蟹。拟穴青蟹属于广温、广盐、肉食性名贵海产品,营养丰富,肉质好,深受人们喜爱。青蟹是汕头市传统特色优势海水养殖品种,但是,自2004年起,汕头市青蟹养殖遇到了严重的病害问题,每年9~11月,牛田洋围垦区养殖的青蟹病害严重,给当地经济造成了很大损失。近几年来,本课题组对牛田洋养殖青蟹的病害问题进行了较系统深入的研究,已弄清病害的主要类型、病原和病因,查明养殖水体理化因子的恶化和条件致病菌的大量增生是牛田洋青蟹病害爆发的重要原因之一;研究利用中草药进行防治病害的方法,取得一定成效。在上述研究工作的基础上,本论文从生态角度出发,期望通过建立青蟹健康养殖模式,达到防控和降低病害发生的目的。养殖试验在3个半咸水养殖池塘中进行(1号和2号池塘面积各1亩,3号池塘15亩),各池塘放养种类和密度相同(拟穴青蟹与斑节对虾、鲻鱼混养)但养殖模式不同。1号和2号池塘采用半封闭式养殖模式,而3号池塘采用开放式养殖模式,养殖周期共46周;其中,在养殖试验进行35周后,在1号池塘按21Kg/亩放入细基江篱,共养殖约10周。通过比较不同池塘水体理化因子及微生物的变化及差异,探讨半封闭式养殖模式与传统开放式养殖模式的不同点,以及细基江篱对水体环境的修复作用。主要结果如下:与传统开放式养殖模式相比,半封闭式养殖模式养殖水体盐度相对稳定;溶解氧含量较高,有害物质氨氮含量低且稳定在0.01mg/L~0.11mg/L范围内, 7月、10~12月显著低于开放式养殖模式(P<0.05);6~11月水体的无机磷水平,5~7月和9~11月水体的异养菌含量,以及5月、8月、10~12月水体的弧菌含量都显著低于开放式养殖模式(P<0.05)。半封闭模式在未放养细基江蓠情况下,其拟穴青蟹的存活率及池塘亩净收益分别比传统养殖模式提高66.22%和38.46%。放养细基江篱的半封闭式池塘与未放养细基江蓠的半封闭对照池塘相比,水体中溶解氧含量在放养细基江篱10天开始显著高于对照池塘(P<0.05);盐度在放养细基江篱20天开始显著低于对照池塘(P<0.05),并且趋于稳定;放养细基江篱后,水体中氨氮含量从江篱投放20天时的0.29mg/L显著下降到40天时的0.04mg/L(P<0.05)。总体来说,水体中大多数重要理化指标都朝着有利于养殖品种健康生长的方向变化,收获时拟穴青蟹的存活率及池塘亩净收益分别比对照池塘提高22.43%和、60.47%,比传统养殖模式提高103.51%和、122.20%。本研究结果表明,半封闭式养殖模式与传统开放式养殖模式相比,受外界水源质量影响较小,水体中各理化指标及微生物含量没有开放式养殖模式变化剧烈,给各养殖品种提供了一个稳定的生存环境,因此在各品种产量、存活率及收益等方面均高于传统开放式养殖模式;而在半封闭式养殖模式中,加入细基江篱对其水质理化指标产生了明显的改善作用,更加有利于各养殖品种的健康生长,提高了产量、存活率及收益。因此,将拟穴青蟹与斑节对虾、鲻鱼混养,并在养殖后期加入细基江篱的半封闭式养殖模式可以作为一种拟穴青蟹的健康养殖模式加以推广。更多还原

【Abstract】 The mud crab Scylla paramamosain is the dominant species of Scylla cultured along the coast of southern China and also a traditionally cultured species in Shantou. The previous researches on S. serrata (Forskal) in China actually belong to those of S. paramamosain. It is a predacious, eurythermal and euryhaline crustacean with rich nutrition and high quality of meat. However, since 2004, the culture of crab in the Niutianyang culture zone of Shantou has being faced with serious diseases from September to November, and this resulted in high mortality and great economic loss. In recent years, we have done systematic studies on the diseases including the clarities of majoy types, pathogenies and cause of diseases. It was demonstrated that the deterioration of environmental factors and the proliferation of conditional pathogens are the important reasons for the outbreak of crab diseases, and the Chinese medicinal herb showed a positive effect on the controlling and cure of crab diseases.On the basis of above studies, this thesis conducted studies from the ecological aspects, with a purpose to establish a healthy culture pattern for mud crab so as to reduce risks of diseases outbresk. Three brakish water ponds (number 1 and 2 was 667 m~2, and number 3 was 15×667 m~2) were chosen to do the experiments, each pond had a same stocking density of mud crab, sugpo prawn Penaeus monodon and mullet Mugil cephalus (Linnaeus). However, the culture mode was different. The number 1 and 2 ponds were semi-enclosed breeding mode, and number 3 pond was the traditional open breeding mode. Total period of culture was 46 weeks. After 35 weeks, the Gracilaria tenuistipitata was put into pond 1 until the end of experiment. By comparing the variation and diversity of water physical and chemical parameters, and microorgamism as well, differences between the semi-enclosed breeding and open breeding modes, and the repairation of Gracilaria tenuistipitata on culture water were investigated. The results as follows:Compared with the traditional open breeding mode, a more stable water salinity, higher content of dissolved oxygen and lower ammonia nitrogen were observed in the semi-enclosed breeding mode, in which the content of ammonia nitrogen was low and stable in 0.01mg/L~0.11mg/L, which was significantly lower than that in the open breeding mode in July and from October to December (P<0.05). Besides, the levels of inorganic phosphorus from June to November, heterotrophic bacteria from May to July and September to November, and vibrio bacteria in May, August and from October to December in the water of semi-enclosed breeding were significantly lower than those on open breeding mode (P<0.05). Compared with the traditional open breeding mode, the mud crab’s enhance rate of survival rate and net earning per 667 m~2 were respectively 66.22% and 38.46% higher in the semi-enclosed breeding mode’s without G. tenuistipitata.Comparied with the semi-enclosed breeding mode without G. tenuistipitata, the addition of G. tenuistipitata into pond of semi-enclosed breeding mode increased the level of dissolved oxygen which was significantly higher (P<0.05) after 10 days, the salinity was significantly lower (P<0.05) after 20 days and became stable. Water level of ammonia nitrogen was from the initial 0.29mg/L down to 0.04mg/L after 20 days. In general, most of the water parameters became beneficial to animal growth. And the mud crab’s enhance rate of survival rate and net earning per 667 m~2 in the semi-enclosed breeding mode with G. tenuistipitata was respectively 22.43% and 60.47% higher than those in the same mode without G. tenuistipitata, and 22.43% and 60.47% higher than traditional open breeding mode respectively.The present study showed that, compared with the raditional open breeding mode, the water environment of pond with semi-enclosed breeding mode was less influenced by the outside water source, and the physical and chemical characters did not changed so fiercely. Therefore such a mode can give the cultured animals a stable living environment, and thus the yield, survival rate and profit are higher than those in the open breeding mode. The addition of G. tenuistipitata into pond of semi-enclosed breeding mode can obviously improve the water characters, which is good for the healthy growth of cultured animals, and increases the yield, survival rate and profit. So, the semi-enclosed breeding mode mainly cultured crab with P. monodon and M. cephalus, and added with G. tenuistipitata in later stage can be used as a healthy culture mode for crab and worth of generalization.更多还原