Ecological studies on barnacle Balanus rostratus as a new species for aquaculture

1. 日本北部木津湾5、10、20、30和40m的沉降深度和沉降增长在10m处最为频繁。在15个月的时间里，10米和20米深度的藤壶比5米深度的藤壶长得更大。新定居的（1993年）和一岁的（1992年）藤壶被移植并在日本东北部的Okirai湾保存了两年多。2年后，前者的基径为32mm，后者的基径为42mm。这意味着在Okirai湾要长到42毫米需要3、4年的时间。水温对藤壶生长的影响在10、15、20、25个温度条件下，藤壶生长越大，存活时间越长。一年生藤壶对温度的反应与0年生藤壶相同。在20种治疗方案中，藤壶的存活率逐渐下降。结果表明，低于15ºC的温度是该物种维持种群的理想温度。2月中旬已出现沙蝇幼虫分布，3月仅发现少量沙蝇幼虫。塞浦路斯人往往更多地出现在穆苏湾的东半部，而不是西半部。在10-12‰/ml、1-2只/ml、光照条件下，日本Asterionella japonica和北方海硅藻（thalassisira nordenskioeldii）的幼虫生长良好。需要搅拌，以分散幼虫的曝气或推进。4 .随着幼虫数量的增加，对粳稻的取食率从300个/小时（II期）增加到1700个/小时（VI期）。在7种不同的人工基质中，将藤壶沉降在聚氯乙烯（PVC）和橡胶板上。用过的轮胎是一个很好的基质，不仅可以沉淀，而且可以去除上面的藤壶。

1. Settlement depth and growth in the seaSettlement was most frequent at the depth of 10m among 5,10,20,30, and 40m in the Mutsu Bay, northern Japan. Barnacles at 10 and 20m in depth grew bigger than the ones at 5m for 15months. Newly settled (1993) and one-year old (1992) classes of barnacles were transplanted and kept for more than two years in Okirai Bay, north-eastern Japan. They grew 32mm in basal diameter for the former and 42mm for the latter after 2 years. This means it takes 3 or 4 years to grow 42mm in size in Okirai Bay.2. Effect of water temperature on the barnacle growthThe lower the temperature, the bigger newly attached barnacles grew and the more they survived for 200 days among 10,15,20, and 25ﾟC temperature regimes. One-year class barnacles showed the same response to the temperature as those of the 0-year class. Barnacles in 20ﾟC regimes showed gradual decrease in survival. The results show that a temperature lower than 15ﾟC is desirable for this species to sustain their population.3. Distribution of larvaeCyprid larvae had already appeared in mid February, and only a fewnaupliar larvae were found in March. Cyprids tended to appear more in the Eastern half of the Mutsu Bay rather than in the Western half of it.4. Larval rearing and their grazing ratesDiatoms Asterionella japonica and Thalassiosira nordenskioeldii supported good growth of larvae under 10-12ﾟC,1-2 larvae/ml, and irrespective of light. Stirring was needed to scatter the larvae by aeration or by propulsion. Grazing rate to A.japonica was increased with growing the larva from 300 cells/nauplius/h (stage II) to 1700 (stage VI).5. Artificial substrate for settlingBarnacles were settled on poly vinylchloride (PVC) and rubber plates among seven different artificial substrata tested. A used tire would be a good substratum not only for settlement but also removing barnacles from it.