Browsing by Author "Castillo, Nelson M."
ArticleS Kumagai & NM Castillo -
Fisheries Research Journal of the Philippines, 1980 - Fisheries Research Society of the PhilippinesShore-caught milkfish fry (late postlarvae) and artificially-bred, laboratory-reared larvae (0-to 20-day old) were preserved in 5% and 10% freshwater-and/or seawater-formalin solutions after measuring their initial weights and/or lengths. The changes in length and weight were observed at regular intervals. Shrinkage in freshwater-formalin (FWF) was less than in seawater-formalin (SWF). The difference in 5% and 10% concentrations of the same solution was not significant. Wild fry showed a final shrinkage of 5.13% of the initial length in 5% SWF and 5.0 7% in 10% SWF. Shrinkage in laboratory-reared larvae varied from 5.09-8.35% according to the age and/or developmental stage, for the same preservation period of 14 days. In estimating the natural length of milkfish larvae preserved in 5-10% SWF, a 5% shrinkage must be considered. The specimens must be kept in the preservative for at least a week before measurement since it takes at least a week for shrinkage to stabilize. Nothing definite could be said, as yet, for the weight changes in milkfish larvae.
ArticleS Kumagai, VC Bañada, NM Castillo & AS Unggui -
SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development CenterThe results are presented of a study of milkfish fry occurrence in the Philippines, namely at Magaba and at Tubog. There were 2 peaks of fry occurrence in the latter, one in May and another in October, whereas only one peak occurred in the former in May. The possible influence on light intensity on the fry seasons is examined.
ArticleT Senta, S Kumagai & NM Castillo -
Bulletin of the Faculty of Fisheries, Nagasaki University, 1980 - The Faculty of Fisheries, Nagasaki UniversityA total of 551 milkfish eggs was collected by horizontal tows with a fish larval net in the waters around Panay island during the period from April 1976 to June 1979. The maximum number obtained by a single tow was 33 eggs. Most of the eggs were collected from Cuyo East Pass, with some from the waters around the Cagayan Islands and a single egg from the Sibuyan Sea. Almost all the eggs were collected during the period frim March to June, with a peak in April, one month ahead of the peak of fry occurrence. Very often milkfish eggs occurred in shallow waters around islands or close to the coasts, while they were sometimes found at locations remote from land and as deep as 900 m. Water temperatures and salinities at locations shere milkfish eggs were found ranged from 26.7 to 30.8°C and from 32.9 to 34.5 ppt. The eggs were rather evenly distributed from the surface to at least 20 m down. The eggs found in the early morning collections were in the early stages of development; those found later in the day were more advanced. It seems that spawning of mikfish takes place at midnight, and that the incubation period of eggs in the wild is about 20 hours.