Browsing by Author "Kumagai, S."
ArticleA female milkfish, captured at sea, was injected with two hormonal injections of acetone-dried salmon pituitary powder and human chorionic gonadotropin, plus Vitamin B complex. It was stripped, and produced 128,000 ripe eggs with an average diameter of 1.15 mm. Fertilization rate was 38% following artificial fertilization with milt from an uninjected male. A total of 36,000 larvae hatched (74% of fertile eggs) after 26–32 h at 34 ‰ salinity and 27–32°C. The newly hatched larvae measured 3.4 mm in mean total length and possessed a large yolk sac. The mouth of the larvae opened about 54 h after hatching. The larvae were fed with fertilized oyster eggs, rotifers, copepods, brine shrimp, flour and prepared feed, together with Chlorella. A critical period was between the 4th and 6th days with mortality over 80%. The larvae started increasing in length by Day 8, and had the appearance of the wild fry by Day 11. On Day 13 a pigmentation pattern developed and the biggest larva measured 10.0 mm. By Day 18 the larvae measured 12.5 mm, and 14.5 mm by Day 21. A total of 2,859 fry was obtained; the highest larval survival rate obtained from different experimental groups was 46.8%.
ArticleS Kumagai, NM Castillo & VC Bañada -
SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development CenterDaily samplings were conducted in the waters of Batbatan Island from April 17 to June 11, 1977 in order to collect milkfish (Chanos chanos ) eggs. The numbers of eggs collected is tabulated by lunar period. Milkfish fry are more abundant during the new and full moon periods, and periodicity does exist, during the first and last quarter periods.
Technical ReportS Kumagai, T Bagarinao & AS Unggui - 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
Series: Technical report / SEAFDEC Aquaculture Department; no. 6This study was conducted to obtain information for evaluating the present fry fishing practices and for understanding the behaviour of the fry. A description of the milkfish, Chanos chanos, fry fishing gears is presented. Each gear is illustrated and its operation explained.