To study on the spawning condition of the northward migrating saury in adjacent waters to Oki Islands, 25 times horizontal surface hauls with 1.3m, larval net were carried out during the period of main spawning season of the fish from May to June in 1962. And about 5kg. masses of floating seaweeds consisting of those caught with the larval net and those entangled in drift nets from 18 stations, were examined to calculate the number of saury eggs deposited on the weeds.
1) Total number of eggs and larvae collected in the periods of the investigation amounted to 1, 520, 000 and 14, 800 individuals respectively. The number of eggs per lgr. floating seaweeds, to which the eggs attached, varied from 10 to 1, 140, and the average being 388. The number of larvae per haul of larval net was 291.
2) As to the relation between the oceanographical structure and the distributions of eggs and larvae of saury, the following results were obtained.
The eggs of the saury were distributed abundantly along the boundary zone between the 2nd branch of the Warm Tsushima Current and the ‘Offshore Low Temperature Region’, (SHIMOMURA and MIYATA, 1952), but the larvae were distributed abundantly in the coastal water region (the 1st branch of the Current).