128,417 research outputs found
Collection, storage, transport, and acclimation of milkfish fry and fingerlings
No full textThe present methods of collecting fry and fingerlings involve filtration by mobile or stationary devices. The bottom topography of the fry ground, wind direction, and tidal fluctuations are the most important considerations in the design and construction of fry and fingerling catching gear. The behavior of young milkfish (Chanos chanos ) in the different environments where they are exploited determines the catching methods to be employed. Collection, handling, storage, and transport activities expose the fish to undue stress, which contributes to poor survival. The simple method of lowering the salinity of the water medium considerably reduces mortality. Prior acclimation history has significant effects on subsequent survival and adaptation. Although it appears that milkfish fry are more hardy than the fingerlings, both have the same capability for resisting subsequent environmental stress provided sufficient time is given for the fish to recover from previous stress
The ecological aspects of milkfish fry occurrence, particularly in the Philippines
No full textAspects of the time, place, and mechanism of occurrence of milkfish (Chanos chanos ) fry, defined as the postlarvae 10-17 mm in total length and 3 weeks of age are considered. Fry occurrence shows seasonal patterns that differ by latitude. In the Philippines (15-21 degree N), fry appear earlier in the south (December-January) and later in the north (March-April); they disappear earlier in the north (July-August) than in the south (December-January). Greater numbers of fry occur in shore waters during the full moon and new moon periods, largely as a consequence of the greater spawning activity during the quarter moon periods. Fry catch by various active and passive filtering gear is greater at floods and high tide than at low and ebb tide. Milkfish fry occur in and are collected mostly from sandy beaches, particularly the surf zone and in and around river mouths. They appear to be distributed mostly near the surface, with greater numbers nearer shore. It appears that larvae smaller than 9-10 mm are distributed in midwaters, but once they reach this size they come up and are carried inshore by tidal and wind-driven currents
The sense organs and behaviors of milkfish fry in relation to collection techniques
No full textThis paper describes the sense organs and some of the behavioral characteristics of milkfish (Chanos chanos ) fry, based on studies conducted at the Aquaculture Department, SEAFDEC, Philippines and at Kagoshima University, Japan in 1982. Based on the experimental results obtained and the observations made in the Philippines, Indonesia, and Taiwan, existing fry collection techniques such as the employment of fish lamps and scare lines are considered effective and rational. Several recommendations are made for improvements of the collection gear and for research on fry behavior
Milkfish research in the Philippines
No full textDevelopment and directions in milkfish (Chanos chanos ) research in the Philippines from 1976 to the present are reviewed and analyzed. The problems of milkfish culture are dichotomous: low productivity vis-a-vis seasons of glut and price fluctuations. To intensify fish production extensive research has been conducted on fertilizer management, reclamation of acid sulfate soils, and pond construction and engineering. Research efforts have also been heavily directed toward increasing fry production through artificial propagation, improvement of fry collecting gear, and increasing fry survival through nutrition, control of parasites, and proper handling. Research on improved icing, packaging, and processing techniques along with market analysis are necessary for maximizing economic returns
Aquatic fungi growing on eel fry montée Anguilla anguilla L
No full textIn the spring 1987, the author investigated of the mycoflora on the eel fry montée (Anguilla anguilla L.) and their environment in Mikołajskie Lake
Milkfish nutrition
No full textThis paper reviews major contributions in the field of milkfish (Chanos chanos ) nutrition since the First International Milkfish Aquaculture Conference in 1976. Substantial progress has been made toward understanding the digestion, foods, and feeding behavior of milkfish, which in its natural habitat apparently feeds on planktonic microorganisms and is most frequently designated as a microphagons planktivore. Vision seems to be the most important sensory mechanism for feeding in fry as well as in juvenilles and larger milkfish. There is very scant information on nutrient requirements and other important aspects of milkfish nutrition. A preliminary study on protein requirement showed that a dietary level of 40% protein was required by fry. Other studies showed that fry responded positively and were easily trained to accept artificial diets. The "deep water method" of growing milkfish practised in Taiwan demonstrated that, with the use of formulated diets, productivity in milkfish aquaculture could be increased three-fold over traditional culture methods, which rely on natural food bases
Milkfish aquaculture in Sri Lanka
No full textMilkfish (Chanos chanos ) fry and fingerlings are abundant in coastal and brackishwater areas in Sri Lanka, yet the industry remains in a stage of underdevelopment. The main seed collection centers are Mannar and Kalpitiya in the northwest and the season is from March to June. The annual fry production potential of the Mannar tidal flats is estimated to be about 4 million. The brackishwater aquaculture potential of Sri Lanka is estimated to be about 120,000 ha. In the past, returns from fry collected from tidal pools and stocked into perennial tanks have been very poor. The recently initiated seed resources survey and investigations into scientific collection, transport, and culture including pen culture should help develop farming of milkfish in Sri Lanka. Polyculture of the species with other fish and shrimp and its culture in salterns are being attempted
Broodstock management and seed production of milkfish
No full textMilkfish (Chanos chanos Forsskal) remains one of the cheapest sources of protein for developing countries in Southeast Asia, particularly in the Philippines. The unpredictable supply of wild fry, the only source of seed for the milkfish farmer, contributed largely to the slow growth of the milkfish industry. Research on the artificial propagation of this fish was, therefore, given emphasis.
Major research achievements in milkfish breeding of the SEAFDEC Aquaculture Department in the last decade include: (1) successful induced spawning of wild and captive breeders using gonadotropin preparations and gonadotropin-releasing hormone analogues (GnRHa); (2) spontaneous maturation and spawning of captive breeders; (3) completion of the life cycle of milkfish in captivity; (4) development of a simple egg-collecting method; and (5) development of techniques for mass production of milkfish fry.
Information on fry ecology and behavior, larval morphology and physiology were also gathered. These published data constitute the bulk of current knowledge on milkfish biology and natural history.
Milkfish breeding technology is currently being pilot-tested in several breeding sites of the Bureau of Fisheries and Aquatic Resources (BFAR). Spontaneous maturation and spawning of milkfish have been verified in four sites which differ in environmental characteristics. The economic feasibility of producing milkfish fry and the socio-economic impact of artificial propagation of milkfish are now being assessed
Milkfish culture techniques generated and developed by the Brackishwater Aquaculture Center
No full textThis paper reviews the work on milkfish (Chanos chanos ) culture techniques conducted from 1973 to 1983 by the Brackishwater Aquaculture Center, the aquaculture research arm of the College of Fisheries, University of the Philippines in the Visayas at Leganes, Iloilo, Philippines. Significant findings and innovative techniques dealing with milkfish fry collection and fingerling production such as those obtained from survival studies of fry during collection, sorting, handling acclimation storage, transport, and rearing in nursery ponds or land-based nurseries are reviewed. Fingerling production utilizing improved methods and techniques is discussed. Results of work on pond culture techniques are presented and discussed
Infection dynamics of two renal myxozoans in hatchery reared fry and juvenile Atlantic cod Gadus morhua L.
No full textIn order to study the infection dynamics of 2 renal myxozoans, Zschokkella hildae Auerbach, 1910 and Gadimyxa atlantica Køie, Karlsbakk and Nylund, 2007 in cultured Atlantic cod, Gadus morhua L. aged 3–19 months, a specific single-round PCR assay and a double-label in situ hybridization protocol were developed. The results demonstrated that the 2 myxozoans show spatial separation of their development with regard to spore formation inside the renal tubules versus the collecting ducts and ureters, as well as temporal separation with Z. hildae proliferating and developing spores only once the G. atlantica infection decreases, despite the presence of both myxozoans in the smallest fry studied. These results strongly suggest within-host competition of the 2 myxozoans with potential suppression of Z. hildae by G. atlantica until G. morhua acquires immunity against G. atlantica. The quantification of the G. atlantica infection inside the renal tubules before and after a 29-day experimental growth performance study using fry from hatcheries with differing filtration systems showed that the intensity of infection with G. atlantica seems to be controlled if prolonged exposure to the myxozoan transmission stages takes place from hatching onwards. Surprisingly, growth rates in the trial were inversely affected suggesting that G. atlantica does not negatively influence cod fry growth performance
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