Studies on Cultural Ground of a Laver, Porphyra tenera KJELLMAN in Matsukawa-ura Inlet-II
Potential Productivity.
1954 Volume 20 Issue 5 Pages 380-385
Details
1954 Volume 20 Issue 5 Pages 380-385
In a previous paper, the authors reported that the inlet water interchanged remarkably with water of Sendai Bay by tidal currents, and that the nutrient salts consumed in laver production during the culture season were probably supplied by nutrient rich water of Oyashio which had flowed into Sendai Bay. It secms reasonable to consider that the distribution of water mass for the period from autumn to early spring in Sendai Bay and the water volume inflowing into the inlet were important factors limitting the production of lavers in this inlet. In this paper, we dealt with the water volume flowing into the inlet by tidal currents and tried to analyse the effect of environmental factors upon the nitrogen and phosphorus contents of laver, and discussed on potential and actual productions of laver in the inlet. The result were summarized as follows;
1. Inflowing water from Sendai Bay was 500 million cubic meters in a flood tide in July. In annual means, it was 293 million cubic meters in a flood tide. This volume corresponds to about 90 per cent of mean water volume of the inlet.
2. It is worth to mention that the nitrogen contents of lavers increased in proportion to the water velocity.
3. In every month except December, the nitrogen contents of lavers were found to be proportional to the volume of inflowing water.
4. A rough estimation showed that about 10.9 per cent of inorganic nitrogen and about 2.1 per cent of the phosphorus supplied from Sendai Bay were utilized by lavers.
5. It was considered that the water volume washing the laver would be an important factor which controls the growth of laver because the nutrient salts were very poor in the inlet water.
