The mechanics of mass occurrence and recruitment strategy of milkfish Chanos chanos (Forsskal) fry in the Philippines
Abstract
The daily and hourly catch of milkfish Chanos chanos (Forsskal) fry in the coast of Hamtic, Panay Island in the Philippines was recorded over a period of 16 weeks, and correlated with time, location, types of gear, and lunar and tidal variations. About 4000 fry were marked and released, scanning electronmicroscopy was employed to examine the feeding habit of the fish. The results obtained suggest an active process governing the occurrence and movement of fry in coastal waters. The appearance of the fry is related to the developmental stage of the fry and is subject to lunar modulation. Interaction with predators in coastal waters has produced diverse and selective antipredator adaptations, such as body transparency, the use of timing (seasonality, tidal conditions), and distribution patterns. The maximization of resource utilization and minimization of resource sharing also occurs in a seasonal basis. High mortality rate in shallow coastal waters is counteracted by high recruitment rate and specific behavioural and physiological adaptations to ensure successful and fast colonization of backwaters. It is suggested that higher food availability in the nursery ground exerts a stronger selective pressure over predation, and act as the major force in the migration from offshore to shore waters.
Description
Contribution No. 107 of the Aquaculture Department, SEAFDEC.
Citation
Buri, P., & Kawamura, G. (1983). The mechanics of mass occurrence and recruitment strategy of milkfish Chanos chanos (Forsskal) fry in the Philippines.Publisher
Kagoshima University Research Center for the South PacificSubject
Type
ArticleISSN
0389-5351Collections
- Journal Articles [1044]
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Milkfish nutrition: a review
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Article
Lactate dehydrogenase isozyme patterns during the development of milkfish, (Chanos chanos (Forskal))
-Kalikasan, The Philippine Journal of Biology , 1981 - University of the Philippines at Los BañosPolyacrylamide disc gel electrophoresis was done to determine the lactate dehydrogenase (LDH) isozyme patterns for fry (5-3 mg), fingerling (6-12 g), pond-size (150-250 g) and adult (6-9 kg) milkfish. The patterns were tissue specific; the different tissues examined, viz., eye, liver, heart, and skeletal muscle had different expressions of LDH isozymes. The resolved patterns appeared to be products of LDH gene loci A, B, and C. Subunits A and B were present in all tissues. A4 and B4 were predominant in skeletal and heart muscle, respectively; the two associated non-randomly in vivo and formed only the heteropolymers A3B and AB3. A liver band, L4, was most conspicuous in the fingerling, pond-size, and adult; it was assumed to be coded by locus C. A negatively charged band, X4, was detected in fully developed ovary and in fry homogenized as whole individuals, but it could not be resolved in tissues of fingerling. Six-mo old stunts and 3-mo old fingerlings had similar LDH patterns for all tissues examined. The patterns for 11-mo old stunts and fingerlings also were similar but the one for the eye of the former was the same pattern resolved for the eye of adults. There was no change in the LDH isozyme patterns of milk fish stunted for 6 mo under different salinity levels (0-5, 15-20, 32-35 ppt). -
Book
Development and management of milkfish broodstock
- 2015 - Aquaculture Department, Southeast Asian Fisheries Development Center
Series: Aquaculture extension manual; No. 62The manual provides developed and refined techniques for collection and transport of spawned eggs and larvae, as well as larval rearing. It also describes the necessary facilities for maintaining milkfish broodstock. Guidelines on transporting broodstock, performing biopsy to determine sex of spawners, collecting and cleaning eggs, packing and transporting eggs to hatchery, incubating and hatching eggs, and packing and transporting of larvae are also provided in the manual. The importance of nutritional quality of the diet in relation to the performance of the milkfish broodstock and quality of resulting eggs and larvae is also explained in the manual. Broodstock feeds are enriched with vitamin C, beta-carotene, and other nutrients for better reproductive performance of broodstock and better egg and larval quality. It also offers formula to initially estimate the number of spawned eggs and determine the hatching rate. The manual guides stakeholders and operators who are interested in setting up breeding facilities for milkfish.
