Monthly Archives: August 2011

freshwater-prawn-training

Freshwater prawn training, enroll now!

On 22 August, the 5-day course on Freshwater prawn hatchery and grow-out will start. Venue is AQD’s Binangonan Freshwater Station in Rizal, Philippines; training fee, Php 6000 or USD 500 per person. Email mreguia@seafdec.org.ph

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2011 releases

AEM 52 Breeding and seed production of the giant freshwater prawn (Macrobrachium rosenbergii)  Maria Lourdes Cuvin-Aralar, Manuel Laron, Emiliano Aralar, Ursan de la Paz (2011) 33 pp An extension manual describing biology, broodstock management, hatchery & nursery operations, feeding management, packing & transport, and health management of the giant freshwater prawn. Each copy costs US$6 Flip through the table of contents Health Management in Aquaculture  Gilda Lio-Po and Yasuo Inui eds. (2011) 316 pp A textbook on the major diseases of cultured fish & crustaceans, as well as prevention & control methods and diagnostic techniques for these diseases. New chapters on histology, probiotics, and epidemiology were added in this edition. Each copy costs US$65 Flip through the table of contents Sustainable aquaculture development for food security …

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Brackishwater pond culture of mud crab

Technology Description Mudcrab has ceased to be an incidental crop in milkfish or shrimp ponds, and is no longer considered a nuisance species which burrows and destroys fishpond dikes. With a new technology, especially on pond design, mudcrab can be successfully grown on its own in brackishwater ponds.     Mudcrab from the wild or from the hatchery may be stocked in brackishwater ponds at a stocking density of 5,000 to 10,000 per hectare. These ponds have to be carefully prepared, including the digging up of trench canals parallel to the dikes when polycultured with milkfish so that crabs do not have to be exposed to high temperatures. In monoculture, trenches are not needed but ponds should be provided with …

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Crab fattening in cages/pen culture of crabs in mangroves

Technology description To produce food through aquaculture without sacrificing the environment is an apt description for the culture or fattening of mudcrab in mangrove areas. The use of net enclosures in mangroves or tidal zones offers a better alternative to pond culture. It also promotes a better image for brackishwater aquaculture that had been linked to the historical clear-cutting of mangroves to make way to ponds. For fattening, the technology involves the construct of small cages with individual cells which are then stocked with lean crabs, weighing at least 100 g (if female native crabs) or 300 g (if female giant crab). Males weighing 200 g (if native) or 350 g (giant crab) may also be stocked individually in the …

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Hatchery & nursery of mud crab

Technology description Although the technology applies to all three species of mud crab (Scylla serrata, S. tranquebarica, S. olivacea), S. serrata or giant/king crab has been the focus of culture due to its economic viability. Healthy mature crabs with complete limbs are chosen as breeders. The crabs are maintained in the tank until they spawn (release of eggs). After hatching of eggs, care is taken to raise the zoea to the megalopa stage in the hatchery. Feed used are Brachionus and Artemia. Water replacement may be from 30 to 80% every 5 days. Megalopae are then transferred to nursery tanks or net cages before they can be stocked in ponds or pens, and are fed mollusks or fish. Hatchery and …

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Virus expected to cost Australian abalone industry

Virus expected to cost Australian abalone industry A herpes-like virus in wild and farmed abalone stocks are wreaking havoc, which could cost the abalone industry in south-west Victoria in Australia up to $5 million in losses this season. The virus responsible for ganglioneuritis, as reported here, is believed to have come from an aquaculture facility in Portland, moving east. Ganglioneuritis causes inflammation of abalone nervous tissue, resulting in curling of the foot and swelling of the mouth. Stakeholders are not very optimistic in their outlook about the situation; divers, such as Peter Riddle, are angry at the State Government’s handling. He thought that it is “too late” to do anything now, “the disease is in the ocean and I don’t …

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Abalone: don’t cramp my style

Abalone: don’t cramp my style Cramped spaces leave abalones with little room for attachment and feeding Abalone farming is a growing aquaculture industry. New frontiers are being explored to expand the production of this valuable commodity, which has various researchers testing the waters in terms of culturing the tropical abalone Haliotis asinina in sea cages. Since studies have shown that stocking density has an inverse relationship with the growth of abalone, the trick is to find a middle ground wherein a given area could still be able to support the growth of abalone.   This begs the question: Does the shelter surface area (SSA) of mesh cages have an effect on the feeding, growth and survival of the tropical abalone? …

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In abalone culture, omnivores rule

In abalone culture, omnivores rule Diets with both plant and animal sources strike the perfect balance between nutritive content and cost A prized aquaculture commodity, the tropical abalone Haliotis asinina has a high market demand in both local and export markets. Because of this, researchers are trying to come up with diet formulations that could support greater growth while minimizing feed cost. Abalones are herbivores in their natural habitats, feeding mostly on macroalgae like seaweeds. In the culture environment, however, experiments from Taiwan have noted that abalone juveniles fed formulated diets had 65% greater growth than those fed solely with macroalgae. In addition, they were found to contain relatively higher protein content than the seaweed-fed abalone. Formulated feed must contain …

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Abalone: feed, mark, let go

Abalone: feed, mark, let go A safer and easier way of tagging abalone for stock enhancement is feeding them a formulated diet In the wild, abalone population has been declining. One way of replenishing this is through stock enhancement in marine reserves, sanctuaries or other protected areas. One way of determining the activity’s success is by monitoring tagged abalones after they are released in the wild. And therein lies the problem: the lack of effective tagging or marking methods. Ideally, tags used in stock enhancement should be able to mark small individuals, detectable in other life stages, is unique to the local population, and suitable for identification of individuals from particular releases. Tags should also be inexpensive to apply and …

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Papaya, malunggay, ipil-ipil and Azolla: must-haves for abalone?

Papaya, malunggay, ipil-ipil and Azolla: must-haves for abalone? Abalone need green leafy “vegetables,” too Abalone, being herbivores, are known to feed on seaweeds in the wild. However, seaweeds like Graciliariopsis bailinae are economically important in themselves, being sources of valuable agar. Seaweeds just can not be used as feed. Hence, locally available plants may just be the right supplement or replacement for expensive components in formulated feeds for abalone. In the Philippines, the terrestrial plants Carica papaya, Leucaena leucocephala, Moringa oliefera, locally known by their less-daunting names papaya, ipil-ipil, and malunggay, respectively, may be the ideal candidates for this purpose. A freshwater fern, Azolla pinnata, is another potential alternative, being incorporated in the diets of tilapia and carp to promote …

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Navicula + abalone mucus = high metamorphosis

Navicula + abalone mucus = high metamorphosis One of the major problems that have perplexed abalone hatchery operators is the poor settlement or the attachment and metamorphosis of abalone larvae. To increase the production of seeds needed for stock enhancement, suitable inducers for the settlement of abalone larvae have to be provided. Since tests using different abalone species showed that responses to settlement cues vary depending on the species, Wenresti Gallardo and Shelah Mae Buen-Ursua of SEAFDEC/AQD decided to test the effect of larval settlement inducers on the tropical abalone Haliotis asinina. Inducers tested included abalone mucus, Navicula sp., Navicula + mucus, mixed diatoms, and mixed diatoms + mucus. Variables requiring mucus were produced by allowing a juvenile abalone to …

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Substrate matters

Substrate matters Even bottom feeders like abalone know the importance of good substrates Marine invertebrates use a range of physical, biological and chemical signals to influence their metamorphosis and larval settlement. In the abalone hatchery environment, these could include food sources and appropriate substrates. To determine what combination of substrate and food source is best for abalone larvae, Rolando Gapasin and Bernice Polohan of SEAFDEC/AQD subjected Haliotis asinina postlarvae to different “substrate-diatom” complexes, together with gamma-aminobutyric acid or GABA. Substrates made of plexiglass, rubberized canvas, fibrocement board and corrugated plastic were placed on the floor bottom of four plexiglass aquaria. Each of these were then inoculated with the following diatom species: Amphora sp., Nitzchia cf. frustulum, a 1:1 combination of …

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Abalone: we need our space

Abalone: we need our space! For abalone to grow well, low stocking rate is good, high stocking bad, and reduced oxygen downright ugly As one of the major countries harvesting abalone, the Philippines is mostly dependent on wild catch since commercial grow-out system for Haliotis asinina is still a pioneering effort. Due to the low profit margin in land-based culture systems, alternative means such as sea cages are being pursued.  A study conducted by Emmanuel Capinpin Jr and his colleagues determined the effects of different stocking densities on the growth, feed conversion ratio (FCR) and survival of abalone using the cage system. Employing three trials using different stocking densities, the researchers raised abalone, with sizes ranging from 16-20 mm and …

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Abalone grow-out culture

  Technical Assumptions Initial size 2.0 cm, 1.5 g (P5/pc)     Final size 5.5 cm, 50 g (P300/kg, 20 pcs/kg) Culture period (months) 9 Seaweed price (P/kg) 4 Number of crops/year 3-4 Survival rate (%) 90% Feed Conversion Ratio 20-25 Project Duration (years) 4   Investment Capital outlay  30,000 Mesh cages 19,600 Long line 7,400 Anchors 2,000 Other materials 1,000 Investment cost (x 3 crops (VC)) 98,640 Abalone juveniles  21,000 Salary, extra labor 1,860 Seaweeds 10,020 Total capital investment required 128,640   Costs-and-Returns Item 1 module Revenue/crop (189 kg/module x P300/kg) 56,700 Variable cost (P) 32,880 Fixed cost (P) 10,112 Total production cost (P) 42,992 Net income/crop (P) 13,707 Net income/year (P) 41,122 Return on Investment (%) 137 Payback …

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Abalone hatchery & nursery

      Technical Assumptions Project duration 5 years Number of breeders, female + male (70-80g) 800+200 pcs Group spawning frequency per month   2x Number of spawning breeders/month 256 Ave. spawning fecundity per breeder 250,000 eggs Total egg production/spawning cycle 32 million Total veliger larvae production (40%) 12.8 million % Settlement rate 2.50% % Survival of early juvenile at 90-day period 4% Total early juvenile production per run (10-15mm) 12,800 % Survival after a 60-day nursery  85% Total advance juveniles production per run  (20-25mm) 10,880 Number of production cycles per year 20 Total juvenile production per year 217,600   Investment Capital Investment 1,061,000 Annual Depreciation 93,942 Depreciation per crop 4,697 Salvage Value after 5 Years 602,125   Costs-and-Returns Items …

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