有用海藻類の地理的分布と水温との関係について

Abstract

The authors reviewed available data on the geographical distributions of five species of seaweeds that are found on the coasts of Japan and are of considerable economic importance, and it was examined what relations are found between these algal distributions and the annual averages or annual cycles of the surface water temperature at the 38 coastal stations. The results are as follows: 1. The palatable brown alga “wakame”, Undaria pinnatifida (HARV.) SUR., is distributed in the waters where annual average of surface water temperature is within the range of 10-19°C. Annual landing of this seaweed is greater in the waters having annual average surface temperatures of about 12°C and about 19°C than in those having any other temperatures. 2. Among the agar-agar seaweeds, Gelidium Amansii LAMX., G. japonicum (HARV.) OKAM. and Acanthopeltis japonica OKAM. are distributed in the waters where annual average of water temperature is not lower than 10, 16 and 17°C respectively. 3. The laver, Porphyra tenera KJELLM., is distributed in the waters where water temperature averages 11-21°C annually. 4. Examination of the annual cycle of water temperature indicates that the growth and distribution of most of these seaweeds are probably affected critically by the water temperatures in a particular period or certain periods of the year rather than by the annual average temperatures, especially near the borders of the distribution range. Since the geographical distributions of the above-named seaweeds along the Japanese coasts is thus closely correlated to the annual average and annual cycle of surface water temperature, it seems that the latter can be used as a criterion in selecting the suitable sites for the artificial propagation of these seaweeds.