Long-Term Relationship between Velocity of the Earth Rotation and the Catch Volume of Japanese Sardine (Sardinops melanostictus)

Abstract

The volume of the catch in Japanese sardine has varied over a 60–68 year cycle. In this cycle, a high catch occurs one or two decades and a low catch continues for the rest of the period. This cycle was observed irrespective of any oceanographic conditions around Japan. Parallel cycles on sardine catches have been reported in various regions in the world, and that the period of the cycles and the direction of the changes are similar in distant regions all over the world. This paper examined the relationship between the speed of the Earth’s rotation and the sardine catch volume. The results of this paper include : (i) The cyclical changes in the catch volume of sardine and the Earth’s rotation rate have similar time-scale of about 60 years; (ii) The coefficient of determination between sardine catch volume and the Earth’s rotation rate showed high values, total period for 63 years about R²=0.38 (first period), R²=0.71 (second period) and, R²=0.80 (third period), R²=0.41 (total period), and (iii) Relationship between the fluctuations of the Earth rotation rate and the changes of the primary production volume in the ocean surface was consistent. It was also suggested that original factor behind these phenomena can be explained by the movement of the Earth‘s liquid outer core.