Comprehensive Notes on Principles of Philippine Aquaculture

History and Global Context of Aquaculture

• Early Origins in China: Aquaculture began in $2500$ B.C. in China. The culture of carp was referred to as "lee" under the authority of Emperor Lee.

• First Written Record: Fan Li wrote the first known treatise on fish culture in $500$ B.C.

• Indonesian Development: In the $15^{th}$ century, brackishwater aquaculture originated in Indonesia with the culture of milkfish in embanked coastal areas known as "tambak."

• Coastal Aquaculture in Japan: Oyster farming is considered the oldest form of coastal aquaculture, dating back $2000$ years in Japan. Seaweed culture in Japan commenced later, in $1952$.

• Asia as the Industry Leader: Asia is considered the global powerhouse of aquaculture. In $1992$, the continent produced $88.2\%$ of the global aquaculture output.

Overview of Philippine Fisheries

• Global Ranking (2003): The Philippines ranked $8^{th}$ globally in total production, with $3.62$ million metric tons of fish, crustaceans, mollusks, and aquatic plants. This contributed $2.5\%$ to the total world production of $146.27$ million metric tons.

• Aquaculture Ranking (2003): The Philippines' aquaculture production was $0.459$ million metric tons, ranking $11^{th}$ in the world and sharing $1.1\%$ of the global total of $42.3$ million metric tons (value approximately $600$ million dollars).

• Aquatic Plant Production: The Philippines is the world’s $2^{nd}$ largest producer of aquatic plants (including seaweeds). It produced $0.989$ million metric tons, representing nearly $8\%$ of the global total of $12$ million metric tons.

• Milkfish Status: Milkfish (Chanos chanos) is the national fish of the Philippines and is the second-ranking fishery export after seaweeds.

• Top Producers: Pangasinan is the top milkfish producer, yielding $45,000$ metric tons between $2003$ and $2005$ ($16.7\%$ of national production).

• Per Capita Consumption: The average per capita consumption of fish in the Philippines is $36\,kg$.

Philippine Fishery Sub-sector Production (2001–2005)

• 2001 Statistics:

  • Total Production: $3,166$ ('$000\,t$)

  • Commercial: $976$ ('$000\,t$) [$30.8\%$]

  • Municipal: $969$ ('$000\,t$) [$30.6\%$]

  • Aquaculture: $1,221$ ('$000\,t$) [$38.5\%$]

  • Growth: $10.8\%$ from previous year.

• 2002 Statistics:

  • Total Production: $3,369$ ('$000\,t$)

  • Commercial: $1,042$ ('$000\,t$) [$30.9\%$]

  • Municipal: $989$ ('$000\,t$) [$29.4\%$]

  • Aquaculture: $1,338$ ('$000\,t$) [$39.7\%$]

  • Growth: $9.6\%$

• 2003 Statistics:

  • Total Production: $3,619$ ('$000\,t$)

  • Commercial: $1,109$ ('$000\,t$) [$30.6\%$]

  • Municipal: $1,055$ ('$000\,t$) [$29.2\%$]

  • Aquaculture: $1,454$ ('$000\,t$) [$40.2\%$]

  • Growth: $8.6\%$

• 2004 Statistics:

  • Total Production: $3,924$ ('$000\,t$)

  • Commercial: $1,137$ ('$000\,t$) [$28.9\%$]

  • Municipal: $1,059$ ('$000\,t$) [$26.9\%$]

  • Aquaculture: $1,726$ ('$000\,t$) [$43.9\%$]

  • Growth: $18.7\%$

• 2005 Statistics:

  • Total Production: $4,163$ ('$000\,t$)

  • Commercial: $1,135$ ('$000\,t$) [$27.3\%$]

  • Municipal: $1,132$ ('$000\,t$) [$27.2\%$]

  • Aquaculture: $1,895$ ('$000\,t$) [$45.5\%$]

  • Growth: $10.4\%$

• 5-Year Average:

  • Total: $3,648$ ('$000\,t$)

  • Commercial: $1,079.8$ [$29.7\%$]

  • Municipal: $1,040.8$ [$28.7\%$]

  • Aquaculture: $1,526.8$ [$41.6\%$]

  • Growth: $11.6\%$

Major Species Produced in Philippine Aquaculture (2004)

• Seaweeds: $1,204,807.56$ Metric Tons ($70.2\%$ or up to $77\%$ in pie chart data).

• Milkfish: $273,593.36$ Metric Tons ($15.9\%$ or $17\%$ in chart data).

• Tilapia: $145,86.36$ Metric Tons ($8.5\%$ or $6\%$ in chart data).

• Others: $92,757.38$ Metric Tons ($5.4\%$

• Total Production: $1,717,026.66$ Metric Tons.

Detailed Taxonomy of Philippine Cultured Species

• Seaweeds: Mainly Kappaphycus spp. and Eucheuma spp.

• Milkfish: Chanos chanos.

• Tilapia: Primarily Nile tilapia (Oreochromis niloticus).

• Shrimp: Mainly jumbo tiger shrimp (Penaeus monodon).

• Carp: Mainly bighead carp (Aristichthys nobilis).

• Oyster: Slipper-shaped oyster (Crassostrea iredalei).

• Mussel: Green mussel (Perna viridis).

Commodity Types and Environmental Impact

1. Finfish: Standard focus of production.

2. Crustaceans: High-value species.

3. Mollusks: Cultivation is environmentally beneficial as they can filter water. However, their metabolites contribute to organic loads. Overuse in Korea ($185\,t/km$) and Japan ($33\,t/km$) led to self-pollution and environment deterioration as ecological limits were reached.

4. Seaweeds: The most environmentally compatible form. They consume dissolved nutrients and produce oxygen.

Aquaculture Sector Breakdown (2003)

• Production Share:

  • Marine fisheries: $77.23\%$

  • Aquaculture: $17.70\%$

  • Inland fisheries: $5.07\%$

• Aquaculture Systems Production:

  • Seaweed culture: $67.99\%$

  • Brackishwater fish ponds: $16.84\%$

  • Freshwater fish ponds: $4.95\%$

  • Freshwater fish cages: $3.63\%$

  • Others: $4.12\%$

• Production by Tonnage: Seaweed ($988,889\,t$), Milkfish ($202,973\,t$), Tilapia ($109,373\,t$), Jumbo tiger shrimp ($34,997\,t$).

• Milkfish Pond Methods:

  • Extensive: Shallow-water, straight-run (traditional/improved).

  • Modified Extensive: Deep water, plankton-based, multi-size stocking, modular/progression systems.

  • Semi-intensive.

  • Intensive.

Principles of Sustainable Aquaculture

• Definition: The management and conservation of the natural resource base through technological and institutional change to satisfy human needs for current and future generations.

• Criteria: Must be environmentally non-degrading, technically appropriate, economically viable, and socially acceptable.

Selection of Species for Culture

Biological Considerations

1. High growth rate and production under culture conditions.

2. Size/age at first maturity: Should reach marketable size before maturity.

3. Ability to breed easily in captivity.

4. High fecundity and frequency of spawning.

5. Larvae must accept artificial feeds.

6. Trophic level: Species low on the food chain are preferred for low-priced products.

7. Hardiness: Tolerance to unfavorable conditions.

Economic Considerations

1. Consumer acceptance.

2. Market availability.

Natural Food in Ponds

• Lab-lab: A benthic community comprising cyanobacteria, diatoms, and associated invertebrates.

• Lumut: (Filamentous algae) Primarily Chaetomorpha spp. with associated Cladophora and Enteromorpha.

• Plankton: Microscopic diatoms, algae, and zooplankton.

Soil Properties and Management

• Soil pH: Near neutral to slightly alkaline ($7$ and slightly above) is ideal.

• Organic Carbon Content:

  • Unproductive: < 0.5\%

  • Medium productivity: $0.5\text{--}1.5\%$

  • High productivity: $1.5\text{--}2.5\%$

• Carbon to Nitrogen (C:N) Ratio:

  • Fast mineralization: < 10

  • Moderately fast: $10\text{--}20$

  • Slow: > 20

• Nutrient Status:

  • Major requirements for phytoplankton: Nitrogen (N), Phosphorus (P), and Potassium (K).

  • Phosphorus ($P_2O_5$) is the single most critical nutrient for pond maintenance.

    • Poor: < 30\,ppm

    • Average: $30\text{--}60\,ppm$

    • Good: $60\text{--}120\,ppm$

    • High: > 120\,ppm

  • Soil Nitrogen Levels:

    • Low: < 250\,ppm

    • Medium: $250\text{--}500\,ppm$

    • High: > 500\,ppm

Liming Principles

• Definition: Application of acid-neutralizing compounds (Calcium or Magnesium).

• Acid Classification by pH:

  • Neutral: $6.6\text{--}7.5$

  • Slightly acidic: $6.1\text{--}6.5$

  • Moderately acidic: $5.6\text{--}6.0$

  • Strongly acidic: $5.1\text{--}5.5$

  • Very strongly acidic: $4.5\text{--}5.0$

  • Extremely acidic: < 4.5

• Causes of Soil Acidity:

  1. Adsorbed/solution $H^+$, $Fe^{3+}$, and $Al^{3+}$. Hydrolysis of $Fe^{3+}$ and $Al^{3+}$ produces $H^+$.

  2. Leaching of basic cations ($Ca$, $Mg$, $K$, $Na$) by heavy rainfall.

  3. Oxidation of $NH_4^+$ and $S^{2-}$ by microbes.

• Nitrification Process:

  • Step 1: $NH_4^+ + 3O_2 \rightarrow 2NO_2^- + 4H^+ + H_2O$ (facilitated by Nitrosomonas bacteria).

  • Step 2: $2NO_2^- + O_2 \rightarrow 2NO_3^-$ (facilitated by Nitrobacter).

• Acid Sulfate Soils: Characterized by "jarosite" (yellow mottles). Acidity is corrected by increasing pH to approximately $5.9$. At this pH, hardness is $20\,mg/L$ and base unsaturation is $0.2$. Caution: Overliming creates phosphorus/micronutrient deficiencies.

• Factors Determining Lime Requirement: Initial pH and Buffering Capacity (resistance to pH change).

• Benefits of Liming: Enhances fertilization effect; prevents pH swings; adds calcium and magnesium for physiology.

• Water Parameters:

  • Total Alkalinity: Total quantity of titratable bases (bicarbonates, carbonates, hydroxides).

  • Hardness: Concentration of divalent salts ($Ca$, $Mg$, $Fe$, etc.).

Liming Material Calculations

• Neutralizing Value (NV): The ability of a material to neutralize acidity.

• Neutralizing Efficiency (NE): Dependence on the fineness of the mixture.

• Formula for Tons of Limestone Needed:     $\text{tons limestone} = \frac{\text{tons/acre } CaCO_3}{NV \times NE}$     Example: $3.0 \div (0.85 \times 0.71) = 4.97$ tons.

Properties of Liming Materials

Fertilization Requirements and Application

• Phytoplankton Needs: Carbon dioxide ($CO_2$), water, sunlight, and minerals (N, P, K, Ca, S, Fe, Mn, Cu, Zn).

• Application Methods:

  • Solution: Dissolved and distributed.

  • Broadcast: Applied in dry form.

  • Platform: Placed on a platform $2\text{--}3\,m$ from the bank on the windward side.

• Calculation:     $\text{Actual fertilizer (kg)} = \frac{\text{kg nutrient requirement}}{\% \text{ nutrient in material}}$

Organic Manures

• Role: Provides nutrients; improves soil structure/fertility; enhances mineralization via bacterial growth. Effective mainly in deep ponds.

• Manure Compositions:

  • Fresh Duck Manure: $57\%$ water, $26\%$ Organic Matter ($O.M.$). Per $100\,kg$: $10\,kg$ carbon, $1.4\,kg$ $P_2O_5$, $1\,kg$ $N$, $0.6\,kg$ $K_2O$, $1.8\,kg$ $Ca$.

  • Chicken Manure: $56\%$ water, $26\%$ $O.M.$, $1.6\%$ $N$, $1.5\%$ $P_2O_5$, $0.9\%$ $K_2O$, $2.4\%$ $Ca$.

• Application Rates: 1 t/ha/crop for chicken manure; associated inorganic doses of urea and $16\text{--}20\text{--}0$ at a ratio of $1\text{--}2:1$ at $150\text{--}200\,kg/ha/crop$.

• Problems: Extreme variability in composition; risk of oxygen depletion/fish mortality due to rapid decomposition.

Carrying Capacity and Intensification

• Definition: The number of individuals an environment supports without significant negative impacts.

• Increasing Capacity:

  • Increasing gate size.

  • Installing separate drain gates opposite large ponds.

  • Using pumps (more cost-effective than deepening the pond by $20\text{--}25\,cm$). Pumping allows biomass loads of $3,000\text{--}4,000\,kg/ha$ in semi-intensive ponds.

• Critical Standing Crop: The point where natural food (even with fertilization) can no longer meet nutrient requirements.

• Culture Intensity:

  • Extensive: Large areas, relies on natural production.

  • Semi-intensive: Supplements natural production with artificial feed.

  • Intensive: High stocking, high water exchange, relies primarily on artificial feed.

Fish Nutrition and Feeds

• Cost Factor: Feed represents greater than $50\%$ of variable operating costs.

• Feed Categories:

  • Supplemental: Adds to nutrients existing in the environment.

  • Complete: For intensive systems where environment provides no nutrients.

  • Life-stage classifications: Larval, Starter, Grower, Finisher, Broodstock, Maintenance.

  • Compositional types: Practical, Semi-purified, Purified.

  • Moisture types: Wet ($50\text{--}70\%$), Moist ($35\text{--}45\%$), Dry (<10\%).

• Proteins: Required for growth and maintenance. Made of Amino Acids.

  • 10 Essential Amino Acids (EAA): Arginine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Tryptophan, Threonine, Valine.

  • 10 Non-essential (NEAA): Alanine, Asparagine, Aspartic acid, Cysteine, Serine, Glutamic acid, Glutamine, Glycine, Proline, Tyrosine.

  • EAA Deficiency: Results in decreased growth, mortality, and malformation.

• Carbohydrates: Used as texturizers, binders, and fillers. Least expensive energy source; many fish have limited ability to metabolize them.

• Fats and Lipids: Source of essential fatty acids for cell membranes and hormones; aids absorption of sterols and vitamins.

  • Saturated: Solid at room temperature (e.g., lard).

  • Unsaturated: Liquid at room temperature (e.g., EPA, DHA).

• Vitamins: Organic micronutrients for metabolism.

  • Fat-soluble: A, D, E, K.

  • Water-soluble: C, B-complex.

• Minerals: Necessary for osmotic balance.

  • Macrominerals: $Ca$, $P$, $S$, $Na$, $Cl$, $K$, $Mg$.

  • Essential Trace: $Fe$, $Cu$, $Mn$, $Co$, $Zn$, $I$, $Mo$, $F$, $Se$.

• Additives:

  • Pigments: Astaxanthin or Cathaxanthin for flesh color.

  • Antioxidants: BHT, BHA, Ethoxyquin, Tocopherol.

Feed Formulation and Management

Proximate Analysis

• Crude Protein: Measured by Kjeldahl method ($\text{Protein} = \text{Nitrogen} \times 6.25$).

• Crude Fat: Soxhlet apparatus.

• NFE (Nitrogen Free Extract):     $\text{NFE} = 100 - (\text{cp} + \text{cfat} + \text{cfiber} + \text{cash})$

Performance Metrics

• Feed Conversion Ratio (FCR):     $\text{FCR} = \frac{\text{Total Feed}}{\text{Weight Gain}}$

• Growth Rate:     $\text{Growth Rate} = \frac{\text{Final Weight} - \text{Initial Weight}}{\text{Time}}$

• Feed Efficiency (%):     $\text{FE} = \frac{1}{FCR} \times 100$

Formulation Constraints

• Soybean: Fishmeal replacer (limit $20\text{--}35\%$ for milkfish/tilapia; $10\text{--}20\%$ for shrimp).

• Copra Meal: Limit $15\text{--}20\%$ due to low digestibility and mycotoxin risk.

Fish Diseases: Viral and Bacterial

Viral Characteristics

• Size: $10\text{--}300\,nm$. Pass through $0.5\,micron$ filters.

• Structure: Capsid (capsomeres) and nucleic acid (RNA or DNA).

• Viral Nervous Necrosis (VNN): Caused by Nodavirus ($20\text{--}25\,nm$). Impacts grouper/seabass larvae; yields $50\text{--}95\%$ mortality. Pale liver, empty gut.

• Grouper Iridovirus (TGIV): ($220\text{--}240\,nm$). Symptoms include anemia and spiraling swimming. $60\%$ mortality.

• Sleepy Grouper Disease (SGD): Iridovirus ($130\text{--}160\,nm$). Extreme lethargy.

Bacterial Characteristics

• Classification: Secondary (opportunistic) or Primary (obligatory).

• Vibriosis: Caused by Vibrio spp. (V. alginolyticus, V. anguillarum, V. vulnificus). Signs: Anorexia, dark body, red spots.

• Motile Aeromonad Septicemia: Systemic invasion of blood.

• Streptococcal Infection: Erratic swimming, exophthalmia (pop-eye), and corneal opacity.

Fungal and Parasitic Diseases

Fungal Diseases

• Characteristics: Heterotrophic, filamentous hyphae forming mycelium. Grow via apical growth.

• Ichthyophoniasis: Caused by Ichthyophonus sp. Internal organs covered in whitish nodules ($2\,mm$). No known treatment.

Parasitic Diseases

• Definitions: Ectoparasites (external) and Endoparasites (internal).

• Symbiosis types: Commensalism, Mutualism, Parasitism.

• White Spot Disease ("Ich"):

  • Freshwater: Ichthyophthirius multifiliis ($50\text{--}1000\,\mu m$).

  • Marine: Cryptocaryon irritans ($300\,\mu m$).

  • Treatment: Increase temp to $30^{\circ}C$ for $6\,h$; formalin ($25\,ppm$) + malachite green ($0.1\,ppm$); or CuSO4 ($0.5\,ppm$) for $5\text{--}7$ days.

• Trichodinids: Trichodina, Trichodinella, Tripartiella. Attach to gills/skin, interfering with respiration.

• Brooklynella: Causes extensive skin damage/hemorrhage. Treatment: $100\,ppm$ formalin bath for $1\,h$.

Parasite Life Cycles

• Direct: One host.

• Indirect: Multiple hosts (Intermediate and Final).

• Larval Names:

  • Monogeneans: Oncomiracidium (ciliated larva).

  • Digeneans: Miracidium (hatched), Cercariae, and Metacercariae (encysted).

  • Nematodes: Often utilize arthropods as intermediate hosts; some are viviparous (Camallanoidea).

Specialized Systems

• Zero Exchange Systems: Consequential systems that confine animals and require extremely limited water use, minimizing interaction with the external environment.