Algae Culture The culture of algae for feeding larvae and post- larvae through fertilization and water management has been in practice in traditional finfish culture. Greater interest in intensive culture, b/c of the need for live foods in rearing larvae. Integral part of shrimp and prawn hatcheries. Several species of microalgae are cultured for experimental purposes in laboratories or for commercial use in special tanks and carboys.
Contd.. Commonly cultured algal species according to FOX (1983) are: Bacillariophyacae Haptophyacae Chrysophyacae Chlorophyacae Chryptophyacae Cyanophyacae
Culture Techniques The techniques presently employed differ somewhat according to species. In all cases, an enriched medium, optimum temp., lighting and aeration are required. Completely pure culture is impossible except in laboratory-scale culture. Fox (1983) describes some of the successful techniques involved capillary pipette isolation and the maintenance of stringent aseptic conditions.
Contd… Most common culture medium used in mass production is filtered surface seawater enriched with essential growth nutrients. Alternative is synthetic seawater medium, consisting of distilled water, growth nutrients and artificial sea salts. Fox (1983) cites Guillards F/2 medium that has received extensive use and is suitable for the growth of most algae. The macronutrients in this medium includes nitrate, phosphate and silica. Inorganic include ferric chloride, the chelate EDTA, and a number of trace elements.
Contd… Organic micronutrients include the vitamins thiamin (B1), cyanocobalamin (B12) and biotin. Algal culture generally consists of 3-4 main stages: Maintaining a stock culture Cultures are made at regular interval in small flasks (50ml). Culture in large carboys (12 l) Tanks of 300 l or more capacity.
Stock Culture Maintained in small screw-top test tubes, autoclaved for sterilization, using low level enrichment medium for maintenance rather than heavy growth. Constant illumination for flagellate stocks, a 12 hrs photoperiod for diatoms. Light level lux provided by two W cool white fluorescent bulbs. Temperature of about 24C. After one month the stock culture should be transferred to create new culture lines.
2 nd Culture Phase Aliquots (2.0ml) of the stock culture are used to inoculate autoclaved small (about 125ml) Erlenmeyer flasks. Light intensity of about 1500 lux. Aeration may not be necessary, flasks should be shaken to reduce shading. A four day old flask culture is used as inoculum for the next phase.
3 rd Phase Arrangements of carboys l capacity with autoclaveable stopper fitted with an air supply line and a screw-top inoculation tube. Exposures to greater light intensity and provision of small amounts of carbon dioxide for growth. Guillards F medium, diluted to half strength, is reported to give high growth rate. After 4 days of growth in carboys, the final phase can be started.
4 th Phase Large fiberglass tanks are used. Illumination is provided by a series of 40 W fluorescent bulbs. Constant illumination and aeration with air stones or other devices for adequate circulation are necessary. Harvesting is done by siphoning off the supernatant or by skimming cells off the surface. The culture has to be transferred mechanically or by pumping into the bowl of the separator. If possible live algae are directly transferred into larval tanks. Concentrated cultures are frozen for storage.
STATUS OF SEAWEED INDUSTRY Historical Development -In early 60s, discovered abundant supply of wild red algae (seaweeds) in Phil. Waters. -In 70s, mariculture technology was successfully developed. -Since then, extensive farming became a major livelihood of seafarmers. Present Status, Prospects & Global Demands -tremendous & continuous demand of Phil. Seaweed for export market; -generates employment, provides alternative livelihood & improves family income (esp. in coastal communities) -2 nd top export commodity after Tuna w/export. -World 2 nd largest producer of aquatic plants.
BIOLOGY AND IMPORTANCE OF SEAWEEDS Biology of Seaweeds macrobenthic (large & attached) forms of marine algae primitive, simplified structure. has no true roots, stems & leaves (is generally called thallus) photosynthetic red, green, yellow-green, light tan to dark red to brown in color naturally grow in coral reef areas
Importance of Seaweeds *Ecological- serves as primary producers in marine ecosystem - serves as habitat & breeding ground * Economic- source of human food - utilized as fodder & fertilizer - Source of raw material for phycocoloid production a.) carrageenan – for milk, candy, lotion, toothpaste, shampoo, beer, soap CARRAGEENAN b.) agar – used as thickener, emulsifier, gel, forming agent, lubricant, bacteriological culture media c.) algin – used in medicine as antibacterial and ointment
SITE SELECTION & METHODS OF FARMING Site Selection Free from fresh water run-off Clear and clean water >30 ppt salinity Moderate water movement/current Sandy or rocky bottom to corally substrates Should not be exposed during low tide Protected bays Presence of wild stocks Methods of Farming Broadcast method Tubular method Spider Web method Bamboo Raft method (floating) Fixed Monoline method (stake) Multiple Longline method (floating) Lantay method (for nursery) Trianglar
SEAWEED DISEASES & HEALTH MANAGEMENT Seaweed Diseases 1.) ice-ice – thallus becomes whitish in color, eventually causing affected parts to break off. 2.) pitting – occurs at cortical layer wherein cavity is formed due to mechanical wound. 3.)tip darkening – due to senescence (old age) & cold weather which result to loss of color. 4.) tip discoloration – due to aerial exposure & intolerance. 5.) epiphytism & algal parasitism – larval mollusk attached hinges to the thallus, presence of pigmented algae (Rhodophytes), presence due to slow water movement/ turbid water. 6.) Presence of micrograzers and macrograzers COMMON DISEASES OF SEAWEEDS MICROGRAZERS & MACROGAZERS
General Health & Farm Management 1.) Visit farm daily 2.) Keep cultured seaweeds always clean 3.) Check & prune ice-ice infected portion of cultured seaweeds 4.) Tighten loose lines and tie-ties 5.) Repair or replace all broken/damaged materials (bamboo,monolin) 6.) Adjust monolines if necessary 7.) Keep a record of daily observation (weather condition, growth data, abnormalities)
PREPARATION OF MATERIALS & SEAWEED PLOT Preparation of planting materials 1.) Cultivation Rope – monofilament #110 test lbs, polyethylene rope (PER #6-7), flat binder 2.) Tying Matls – soft plastic rope (tie-tie), monofilament #160 test lbs 3.) Support Matls – bamboo, mangrove post, steel bar, PE rope #12/Polypropelene rope #14 4.) Floater – styrofoam (square or round shape), empty plastic bottles Preparation of Seedlings - select young branches using sharp edge knife - tie individual plant using soft plastic rope - immerse plant in seawater to prevent desiccation - Seedlings per cutting
CONTINUATION… Installation of monolines, bamboo raft & stakes - install needed structures whether staking or floating method prior to planting - in fixed off-bottom longline, bull hammer is used to pegged stakes to bottom HARVESTING & POST-HANDLING OF SEAWEED Harvesting - seaweeds are harvested for drying after days of culture - 3 ways of harvesting: 1.) individual plant is untied/cut 2.) both ends of cultivation rope is untied 3.) whole single bamboo raft is brought to shoreline
CONTINUATION… Post-Harvest *Cleaning – clean thoroughly from foreign materials the newly harvested seaweeds *Drying – ground solar drying & hanging method *7:1 (kilos) – wet to dry ratio DOs in drying - dry immediately after harvest - keep seaweed always clean - sun-dry for 2-3 days - maintain moisture content at 35-39% DONTs in initial drying - avoid contact w/sand, dust and dirt - avoid steaming - avoid contact w/freshwater Storage - stored in shortest time possible in clean, cool, dry & well-ventilated places
Basic Assumptions: Days of Culture days Croppings Per Year Length of Cultivation meters No. of Lines Per ¼ Hectare lines Distance Per Seedlings inches Distance Per Cultivation Line meter No. of Seaweed Seedlings Per Line No. of Seaweed Seedlings Per ¼ Hectare ,800 Initial Weight Per Seedlings grams Total Weight Per Seedlings kilos Daily Growth Rate % Total Harvest (net wt.) after 75 days ,655 kls Seedlings for next Cropping kls 2% Biological Loss kls Wet to Dry Ratio :1 Net Dry Weight Yield kls Total Harvest Per Year , kls Price Per Kilo (dried) P SALES Php 75,731.60
CONTINUATION… LESS: Cost of Materials Php 26, Depreciation Cost (20% of matls cost)- 5, Php 31, NET INCOME Php 44, Return On Investment % Payback Period 0.71 year
REFERENCES: HURTADO, A.Q. and R.F Agbayani. The Farming of Seaweed Kappaphycus. Ext. Manual #32. SEAFDEC Aquaculture Department. Iloilo, Philippines Seaweed Farming. Extension, Training & Communication Division (ETCD). Bureau of Fisheries and Aquatic Resources IV-B (MIMAROPA). Quezon City, Philippines. GALICIA, A.M., Jr., et al. Introduction to Seaweed Farming. Seaweed Development Program (SDP). Inland Fisheries and Aquaculture Division. Bureau of Fisheries and Aquatic Resources. Quezon City, Philippines.