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

1.海水中的沉降深度和增长在日本北部Mutsu海湾的5、10、20、30和40米之间的10米处最频繁。在15个月里，10米和20米深的藤壶比5米深的藤壶长得更大。新定居的(1993)和一年生(1992)的藤壶被移植到日本东北部的Okirai Bay，并保存了两年多。术后2年，前者基径增长32 mm，后者增长42 mm。这意味着在奥基莱湾需要3到4年的时间才能长出42毫米的大小。水温对藤壶生长的影响在10、15、20和25ﾟ℃的温度范围内，温度越低，新附着的藤壶越大，存活200天的时间越长。一年生藤壶对温度的反应与零年生藤壶相同。在20个ﾟC组中，藤壶的存活率逐渐下降。结果表明，低于15ﾟC的温度是该物种维持种群的理想条件。2月中旬已出现幼虫分布，3月份仅发现少量无节幼虫。塞浦路斯人往往更多地出现在Mutsu Bay的东半部，而不是西半部。在10~(-12)ﾟC、1~2尾/ml的光照条件下，日本星状硅藻和诺氏海链藻的幼体生长良好。需要搅拌才能通过充气或推进驱散幼虫。幼虫对日本对虾的摄食率从300个/无节幼体/h(阶段II)增加到1700个/h(阶段VI)。在7种不同的人工基质中，将藤壶固定在聚氯乙烯(PVC)和橡胶板上。一个用过的轮胎将是一个很好的衬底，不仅可以解决问题，而且还可以去除其中的藤壶。

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.