Friday , 11 July 2025

Rossea H. Ledesma

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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Tilapia

Why tilapia hatchery/culture? Tilapia, also known as “aquatic chicken,” grows fast and easily breeds in captivity Technology for its propagation and culture requires little input Hatcheries can readily supply the seedstock the industry needs Tilapia has become an effective biocontrol agent for luminous bacteria Generally occupies a smaller area than other culture species

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Milkfish

Why milkfish hatchery? Hatchery technology for large-scale seed production is already established With seasonal shortage of milkfish fry from the wild, the hatchery option is a good one Early fear of getting deformed market-sized milkfish is no longer an issue Increased acceptance from grow-out culturists once its performance had been demonstrated satisfactorily

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Freshwater prawn

Why freshwater prawn culture? High export potential Can be a good alternative to tilapia and tiger shrimp Can be used in polyculture with other species Has an established market niche

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Bighead carp

Why carp culture? Has low protein requirement during culture Can be used as raw material in value-added fish products Can be used in polyculture with other aquaculture species Grows fast, reaching 2-4 kilograms in 4-6 months

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Seaweeds

Why seaweed culture? High return on investment Demand for seaweeds is high in the local and international markets Culture period could be as short as 45 days under optimal conditions Environment-friendly Could be a source of supplemental income for small fisherfolk associations and people’s cooperatives

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Tiger shrimp

Why shrimp culture? New technology on shrimp farming in brackishwater ponds incorporates pollution management Could be integrated with commodities such as tilapia, bivalve, seaweed Environment-friendly techniques, like crop rotation and improvement of feed formulation can be employed Greenwater technology makes it possible to inhibit disease-causing organisms

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Catfish

Why catfish culture/hatchery? Resistant to diseases Can be stocked at high densities Has low requirements for water quality Requires less area required for culture   Technical Indicators Catfish Seed Production Breeders mature in 6-8 months, and can be obtained from lakes, rivers, tributaries and other freshwater bodies. Sexes can be distinguished externally by the presence of the urogenital papillae in males and a round opening in the females at the lower, ventral side of the body. Catfish Grow-out Stocking density ranges from 10-20 pcs/sq. m depending on water quality and supply. Staggered stocking of ponds is done every 15 – 30 days. Sample 30-50 pcs catfish monthly to monitor ABW and adjust daily feed ration. Downloads Catfish Hatchery and Grow-out …

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Mud crab

Why mudcrab culture? A mangrove-friendly or sustainable aquaculture Mudcrab is well-liked for its taste, texture and nutritive value High demand in the local and export markets Could be polycultured with other species, such as milkfish Could be an investment for people’s cooperatives and fisherfolk organizations who manage a mangrove area under a stewardship contract

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