Now showing items 1-8 of 8

    • Article

      Changes in length and weight of milkfish fry preserved in formalin 

      S Kumagai & N Castillo - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Fry shrank immediately after they were preserved in formalin, but from the second week onwards shrinkage was almost nil. Fry in freshwater formalin solutions shrunk less than those in seawater formalin solutions. It is recommended that milkfish Chanos fry be preserved in formalin solutions for 1 wk prior to length measurement and at least for 3 wks before determining body weight.
    • Article

      Changes in the length and weight of milkfish, Chanos chanos, larvae preserved in formalin 

      S Kumagai & NM Castillo - Fisheries Research Journal of the Philippines, 1980 - Fisheries Research Society of the Philippines
      Shore-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.
    • Article

      Developmental and ecological stages in the life history of milkfish Chanos chanos Forsskal 

      P Buri, S Kumagai, V Bañada, A Triño & N Castillo - SEAFDEC Aquaculture Department Quarterly Research Report, 1980 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Seven stages in the life history of the milkfish C. chanos , are recognized and suggested: A, embryonic; B, yolksac larval; C, larval; D, postlarval; E, juvenile; F, subadult; G. adult. An outline is presented of the life history. It is concluded that the milkfish, throughout the known stages of their life history are well adapted and equipped for optimal survival. High swimming performance, broad flexibility in feeding habits, high adaptability to a wide range of physicochemical conditions of the environment are but a few of the adaptations. The main driving force in all developmental stages is the evolutionary response to food distribution and availability followed by predation pressure.
    • Article

      Milkfish fry occurrence pattern in two localities along the Western Coast of Panay Island 

      S Kumagai, VC Bañada, NM Castillo & AS Unggui - SEAFDEC Aquaculture Department Quarterly Research Report, 1978 - Aquaculture Department, Southeast Asian Fisheries Development Center
      The 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.
    • Conference paper

      Occurrence of milkfish eggs in the adjacent waters of Panay Island, Philippines 

      T Senta, S Kumagai & L Ver - In Proceedings of the International Milkfish Workshop Conference, May 19-22, 1976, Tigbauan, Iloilo, Philippines, 1976 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Location of spawning grounds of milkfish is one of the most important steps towards gaining knowledge on the spawning habits of the fish as well as the early life history and nature of its eggs and larvae. The present study is an attempt towards this objective. Surveys were made in selected areas in the sea around the Panay Island and milkfish eggs were collected on several occasions from surface to 20 m depth water by towing with larval nets. The eggs floated in the water in a glass jar. The eggs and newly hatched larvae had the same characteristics as described by Delsman (1929). A comparative study has been made to distinguish milkfish eggs from other more or less similar size pelagic eggs of fishes occurring in the same waters at the same time.
    • Article

      Occurrence of milkfish, Chanos chanos (Forsskal) eggs around Panay Island, Philippines 

      T Senta, S Kumagai & N Castillo - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
    • Article

      Results of drift card experiments and considerations on the movement of milkfish eggs and larvae in the northern Sulu Sea 

      S Kumagai & T Bagarinao - SEAFDEC Aquaculture Department Quarterly Research Report, 1979 - Aquaculture Department, Southeast Asian Fisheries Development Center
      For a period of one year beginning December 1977, drift card experiments were conducted off the western and southern coasts of Panay Island to determine the surface currents in the area. Of a total 2,384 drift cards released during the study, 382 (16.02%) were recovered, 92% of them within 30 days following dispatch. The surface currents in the study area are strongly influenced, in direction and speed, by the prevailing monsoon winds. During the NE monsoon period, the surface currents move away from the coast; during the SW monsoon, toward and/or parallel to the coast. Based on the results, the probable movement and transport of milkfish (chanos chanos) eggs and larvae from the spawning ground to the fry collection ground are also discussed.
    • Article

      Variation in the vertebral number of the milkfish Chanos chanos, collected from various localities 

      T Senta & S Kumagai - Bulletin- Faculty of Fisheries Nagasaki University, 1977 - The Faculty of Fisheries, Nagasaki University
      A total of 2497 milkfish fry were collected in 1976 from nine localities in six countries, viz. India, Thailand, Indonesia, Philippines, Taiwan and Tahiti. Vertebra counts ranged from 40 to 45. The general trend of geographical gradient in vertebral counts in the milkfish was observed to be lower in the west (or otherwise, along continents) and higher in the east (or around oceanic islands). Extremes in the means of vertebral counts by localities were seen in the samples from India with 43.08 and from Tahiti with 43.82. It was suggested that there may be at least four subpopulations among the milkfish throughout the tropical Indo-Pacific waters.