抄録
The diameter, percentages of total hatch, and percentages of viable hatch of eggs of Japanese whiting Sillago japonica were determined for 85 days during the spawning season from early July to late September, and then these relationships were traced.
The diameter varied periodically during the season: it showed the largest size in the early and late part of the season and became smallest in size in the middle of the season. The daily maximum and daily mean percentages of total hatch were almost always above 50% and not rich in variety, but those of viable hatch showed some variations and often decreased below 50%. The diameter had statistically significant correlations with both percentages of viable hatch (p<0.01), but little with those of total hatch. Namely, the larger eggs had a tendency to produce a higher percentage of viable larvae than the smaller eggs. Besides this, the diameter and both percentages of viable hatch also had significant correlations with the water temperature (p<0.01).
