Relationships between growth of Porphyra tenera and its cultural conditions in the natural sea-I

Investigation of the microclimate in the culture net of Porphyra tenera

Abstract

From October 7 to November 28 in 1966, we have examined the cultural conditions for the growth of Porphyra tenera in the Ariake-Sea (Fukuoka Pref.). Then, we have investigated the relationships among growth, injury of fronds and the microclimate of the culture net. The harvest of fronds have been very poor this year, because the injury “Shirogusare” has happend.
Our measurements items are as follows:
1) area of fronds, 2) growth rate of fronds, 3) injury percentage of fronds by colored cells, 4) temperatures of atmosphere, sea water, and culture net, 5) density, pH, desolved oxygen and nutrients (NH₄-N, NO₃-N, PO₄-P) of the sea water, 6) speed of sea water by the tide, 7) the weather, 8) speed and course of the wind, 9) light intensity in the sea water by sun shining.
These data have been obtained continuously, or at least one time per day. We have also obtained some original data about culture conditions, growth, and injury of Porphyra tenera. Some discussions about these relationships are made.