天然海域におけるノリの生育と養殖環境の関係-III

Abstract

In a previous paper the relationship between culture conditions and growth and injury of the leafy fronds of Porphyra was discussed. The present paper once again deals with culture conditions for the growth of Porphyra, but in order to make clear the differences between field locations and its influence on culture conditions, the study location was changed from the Ariake Sea to Tokyo Bay. Observations and the measurements taken are almost same as those explained in the previous paper and these are as shown in Table 1 in the present paper. Tokyo Bay is located to the north of the Ariake Sea, about 250km, and culture in Tokyo Bay is generally begun about half a month earlier than in the Ariake Sea. But by checking the sea water temperature this difference is compensated. These results are shown in Fig. 3. Changes in culture condition factors are very unique for pH and DO2, of sea water from the end of October to November. The changes of pH and DO2 of the sea water can be recognized from Porphyra fronds a vital function in the field. The changes are because of the fluidity of sea water in Tokyo Bay which is less than that in the Ariake Sea. Lightness and light intensity in Tokyo Bay is less than half of that in the Ariake Sea however, lower culture net heights make up for the deficit and thereby the growth rate of Porphyra fronds in Tokyo Bay is similar to that in the Ariake Sea.