Ecological studies on the polyculture of fauna and flora

鱼类与海藻混养是一种有益的水产养殖系统。尽管从生态学的角度来看，它具有重要的意义，但在多元文化系统中却很少受到重视。这可能是由于鱼类和海藻的生长季节不同；鱼在夏季和秋季生长，而海藻在冬季和春季繁殖。在此之前，我们已经发现了与鱼类生长季节相同的夏、秋两季的育无菌性紫尾藻的培养技术。在本研究中，我们研究了鱼类和海藻的混养，无菌的紫菜。第一次试验于1993年8月至1994年2月在Azumacho鱼苗中心的网箱养鱼场进行。采用2个7x7x7m的笼，一个作混养实验，另一个作常规对照实验。每个笼中养殖3岁红鲷，每条约1750尾。在实验网箱中，采用浮网系统培养经过消毒的绿藻。用ABL-330辐射计测定溶解氧和二氧化碳含量。考虑控制笼中pO2为100%，则实验笼中pO2为109.1%。另一方面，控制笼的平均pCO2为100%，实验笼的平均pCO2为96.1%。从以上结果可以看出，与对照相比，实验笼中的pCO2降低到4%，pO2增加到9%。为了了解光照强度和水温对无菌紫藻生长的影响，进行了第二次实验，作为通过藻回收物质的“鱼与环境协调养殖”的基础研究。冬至和夏至前后分别呈现弱光和强光的趋势。冬至前后最高为19.7 mol/m2/day，夏至前后最高为47.3 mol/m2/day。经多元回归分析，多元回归系数为0.74。少

Polyculture of fish and seaweeds is a benefical system in aquaculture. In spite of its importance from the ecological point of view, little attention has been given in polyculture system. This may be due to the fact that fish and seaweeds have different growth seasons ; fish grow in summer nd autum while seaweeds propagate in winter and spring. Previously, we found the culture techniques of sterile Ulva pertusa which grow in summer and autum as same seasons as fish growth. In the presesnt study, we have examined the polyculture of fish and seaweed, sterile Ulva pertusa.The first experiment was conducted in the fish cage culture farm from August 1993 to February 1994 at the Azumacho Fish Seedling Center. Two cages, 7x7x7m, were employed, one for polyculture experiment and the other one for control experiment by the routine method. Three years old red sea bream Pagrus major, about 1750 individuals each, were cultured in each cage. The Chlorophyta, steriled Ulva pertusa was cultured by th … More e floating net system in the experimental cage. Dissolved oxygen and carbon dioxide were measured by Radiometer ABL-330.Considering the value of pO2 in the control cage as 100%, pO2 in the experiment cge stands 109.1%. On the other hand, average pCO2 in the control cage as 100%, pCO2 in the experiment cage stands 96.1%. From the results mentioned above, it may concluded that the pCO2 in the experimental cage decreased to 4% while pO2 augmented up to 9% compared to those in the control cage.The second experiment was also conducted in order to know the efficiences of light intensity and water temperture on growth of sterile Ulva pertusa as a foundamental study of "harmonized fish culture with environment" where substances were recycled through the alga. Tendency of low light and high light intensities were observed around the winter solstice and summer solstice, respectively. The highest value was 19.7 mol/m2/day around the winter silstice and 47.3 mol/m2/day around the summer solstice. In multiple regression analysis, multiple regression coefficient of 0.74 was obtained. Less