The Farming of Seaweeds

Members:

• Pongcol, Esther• Fabillar, Katherine• Molina, Jolevie• Meraflor, Jessica

General Description• Seaweeds are macrobenthic (large and

attached) forms of marine algae. • They have a simplified, primitive

structure compared to higher plants. The vegetative plant body, generally called “thallus” has no true roots, stems and leaves.

• They vary in forms, some are branching, leaf-like or bushy type, club like, featherlike, while some form sponge-like encrustations on hard substrates like the rocks, corals and boulders. Seaweeds are generally photosynthetic plants.

Seaweeds are generally cultivated in lagoons or sheltered bays. Seaweeds obtain nutrients directly from the seawater and it is crucial to have currents that flush the site in which the seaweeds are placed. Small cuttings are attached to a line with short lengths of string (known as ‘Tie Tie’) at a density of five cuttings per metre of line. In nature these seaweeds live attached to a solid substrate.

Philippines Seaweed IndustrySeaweeds is one of the important aquaculture commodities in the Philippines. • More than 800 species of seaweeds that has

been recorded in the country. • About 50% of have been found to have

economic uses while 15% are economically important edible species.

• Seaweeds as a fishery resource is one of the export winners in the Philippines. It ranks third among our fishery exports after tuna and shrimp.

• Statistics (BAS) data of 2007, the production estimate was 50,600 MT. Seaweeds for human consumption 160 MT, carrageenan 9,553 MT and kelp powder 1,305 MT. They are exported either in raw forms (fresh or dried seaweeds) or processed forms (carrageenan and kelp powder). The major importing countries of seaweeds are France, Denmark, Japan, USA and UK.

Economic ImportanceThe economic importance of seaweeds or algae, lies on its utilization as food, industry, pharmacy and medicine.

Different species cultured and collected in the Philippines are: Eucheuma

Eucheuma denticulatum Eucheuma spinosum

Caulerpa Kappaphycus

The most popular and commercially cultured species is the Eucheuma cottonii now called Kappaphycus alvarezii due to its fast growing characteristics, easy to culture and high market price.

Seaweeds can be found in the inter-tidal and subtidal zones of the sea.

• Green and brown seaweeds can be found from intertidal to shallower portion of the subtidal zone.

• Red seaweeds are distributed in both zones but their corral line types of species are found in the deeper portions of the subtidal zone.

Daily Growth Rate

• The growth rate of seaweed located in a suitable habitat, even taking into account seasonal variations. A single cutting of 100g can reach a weight of 1kg in 20-40 days, which could yield at least 8 separate harvests per year.

• Formula:

Where:

TW = Total weight of plant after test plantingOW = Original weight of the plant before test plantingNo. of culture days = Period of test planting

Site SelectionCharacteristics of sites suitable for culture:• Pollution free environment

(domestic, agriculture and industrial waste)

• Farm area must be far away from river system or any freshwater tributaries

• Moderate water movement or current to ensure significant nutrient supply

• Sandy or rocky bottom• Protected coves or bay areas in

order to maximize production• Site should not be exposed during

low tide

Eucheuma spp.

On growing techniques for Eucheuma spp.• Good water movement or where there is a rapid

water turnover, but not heavy enough to damage the farm. Water current speed should be between 20 to 40 meters per minute.

• Avoid areas that are near the mouth of rivers or where there is a heavy freshwater runoff. Eucheuma is a purely marine alga. Salinity of the farm area should be from 27 to 35 parts per thousand.

• The area should have a water temperature range between 25°C and 30°C.

• Water depth in the farm should not be less than 2 feet during the lowest tide and more than 7 feet during high tide.

Preparation of the Farm site & other Culture Activities

1. When a site suitable for Eucheuma farming has been selected, secure a permit from the nearest Bureau of Fisheries and Aquatic Resources office which has a direct jurisdiction over the area for legal acquisition. The following are the steps to follow (BFAR, Illustrated Handouts).

2. Cut all grasses and remove all obstacles from the area

3. Remove the rocks, stones, starfishes, sea urchins and other predators

4. Construct a farm house with a drying platform on the selected site

5. Prepare rattan/buri baskets or seed-bin for holding seed stocks

Seed selection and preparation

The ways to prepare the seedlings are:• Use a clean and

sharp stainless knife to cut the branches in order to leave a smooth surface.

• Never cut the branch in a slant position.

• Do not produce seedlings with any cuts at its branches.

Culture Techniques for Eucheuma spp.

Off-bottom (post and line)• This technique is best suited

for lagoons, where there is relatively shallow water at low tide and for small-scale initiatives.

• The lines are regularly checked and the seaweed harvested during the two spring tide periods each month, particularly suited to women farmers.

Longlines• This technique involves the use of line of up to 50m in length,

anchored at each end and with floats attached every 10m or so to support the line .

• This technique is usually employed in water of between 4 and 10m and farmers therefore require access to some sort of boat to access the plots. However, as a result of the necessity of a boat the farmers can access the plots at all times, except for during bad weather.

• The Longline technique for use in deeper water

Rock-based Farming for Spinosum• With this technique the

harvesting of seaweed is done,at low tide and on foot, by simply cutting away the new growth each cycle while leaving enough of the ‘root stock’ for the cycle of growth to start over again.

Bottom Monoline Method• The fixed, off-bottom

monoline method or bottom line method of cultivation is commonly used in commercial farms.

• This method has many advantages over other methods such as the net method used in the past.

• The farm is cheaper to maintain and easier to install.

Floating Monoline Method• The floating monoline method has the following

advantages over the fixed, bottom monoline method:

a) grazing by bottom-associated animals is minimized or eliminated because the plants are raised out of reach of benthic grazers b) plants near the surface of the water column are exposed to more moderate water movement caused by waves.

Maintenance of Planted Seaweeds• Remove silt and prevent epiphytes from lodging on the

seaweeds by shaking cultivation lines, daily. Missing plants should be replaced at once.

Disease/Calamities Management• During disease outbreak, prune affected thallus with

sharp stainless knife givng one centimeter allowance from the affected area. Transfer unaffected plants to other sites. Shake mono lines daily to dislodge epihpytes and silt.

• To avoid loss during typhoons, lower floats along cultivation lines by adding anchors or lengthening the lines of the floats. Maintain 100 to 300 centimeter from the sea bottom to allow the plants to suspend during the period.

Nursery and Farm Management

• Establish a nursery farm in a well-protected area to ensure continuous supply of high quality seedstocks.

• Maintain a thirty-day culture period in the nursery to have young and healthy plants for propagation. Plants should not be overgrown for matured plants won’t make good plant materials.

Seedling Bed• Construct a 5m x 10mx 2 m cage-type seedling

bed. Place seedstocks on it before planting. Immerse it in seawater to prevent from undue stress.

• Seedstock should be planted after a week of stocking.

Harvesting

• Harvest the plants after 45 days culture period either by pruning or total harvest. Select healthy and young plants as seedstock for the next cropping season.

Production of Eucheuma spp.

Kappaphycus

CULTURE PREPARATION

• Prepare the necessary materials such as banca, anchors, soft ties, nylon ropes and then install the needed structures whether staking or floating method prior to planting.

• Source out quality seedlings from the vicinity to ensure easy transport to the farm site and propagules must be protected from direct exposure to sun and rain. Transport container like styrofoam box is best recommended although ordinary jute sacks will suffice.

• Seedlings must be immersed in seawater upon arrival preferably in the seedling bin. Seedlings or propagules to be planted shall be around 100-200 g each. Only young portion of the plant must be selected for planting to ensure faster growth.

PREPARATION OF MATERIALSa. Prepare a measuring stick made of bamboo about 0.64cm (1/4 inch thick), 7.6cm (3 inches wide) & 20.3cm (8 inches) long.b. Wind the flat yarn 25 times around

c. Insert a sharp knife and cut the yarn at one end. Cut similarly the yarn at the other end.d. Get one strip and tie it tightly around one end of the strips to make a bundlee. Split each strip into two and make a tight knot at each tip. One strip is sufficient

f. Tie nylon lines to stakes as shown.

g. After clearing the area, measure the exact dimensions of the farm. Commence posting by using the pointed iron bar or “bara”.

• Careful selection of cuttings is important for successful farming. Choose healthy and strong branches for planting. These are usually found at the center and near tips of a healthy plant. Use a clean sharp stainless steel knife for cutting branches to leave a smooth surface

Culture Techniques for Kappaphycus1. Short Stake and Line MethodCharacteristics:• uses short stakes (60cm long) erected on

seabed & arranged in rows, seeded line has no floats

Advisable for use:• - exposed or very shallow area at spring

low tide

Advantage:• structure easy to construct

Disadvantages:• cannot be farmed on rocky seabeds• supply of stakes getting low• - minimal surface water movement hardly

affects the seaweed• susceptible to grazing

2. Long Stake and Longline with FloatCharacteristics:• - uses long stakes (1-1.5m long) erected on seabed

& arranged wide distance between rows• uses long seeded lines with floats

Advisable for use:• - submerged areas with 0.5-1.5m water depth at• spring low tide

Advantages:• - good water movement even with light wave

action• - seaweed distance from water surface is constant

Disadvantages:• - cannot be farmed on rocky seabed• - supply of stakes getting low• - susceptible to grazing

3. Bamboo RaftCharacteristics:• - uses bamboo poles as floats and weights

as anchors• - seeded lines may or may not have floats

Advisable for use:• - water depth of 1.0m or more at spring

low tide

Advantages:• - good water movement even with light

wave action• - seaweed distance from water surface is

constant• - less susceptible to grazing

Disadvantages:• - bamboos are scarce and expensive• - construction of structure is rather

complicated

4. Lantay MethodCharacteristics:• - Uses bamboo as frames• - Uses nets to cover the whole

structureAdvisable for use:• - For nursery/holding purposesAdvantages:• - Transferable & resistant to

strong wavesDisadvantages:• - capital and labor intensive• - difficult to maintain

5. Spider Web MethodCharacteristics:• - Similar to raft method without bamboo

Advisable for use:• - open bodies of water with depth of 10-20m• - moderately strong waves and water current• - group of farmer or cooperative farming

Advantages:• - high yield and greater flexibility• - no rigid component making it highly

resistant• - self-cleaning and environment-friendly

Disadvantages:• - capital and labor intensive• - difficult to set-up• - serious hazard to navigation

HARVESTING

There are two types of harvesting:1. Partial Harvesting• Done by pruning the initial seedlings planted to fill-

up the allocated planting area after 2-3 weeks period. Harvested after 45-60 days culture for expansion purposes.

2. Total Harvesting• Total harvesting after 45-60 days culture. Initial or

total seedlings requirement are left behind for the next crop.

TRANSPORT OF SEEDSTOCKS• When transport lasts more than 8

hours, use plastic (polypropylene) bags or rice sacks.

• Put cuttings loosely inside the bags and dip them into seawater before loading them.

• Store bags in cool, well-covered and spacious part of the boat. Never place the bags on top of each other.

• Plant transported cuttings as soon as possible. The longer you store them, the more dead cuttings there will be. Usually, about 10% of transported cuttings die.

• Cover them with wet cloth to protect from sunlight, rain or wind.

• Sprinkle cuttings with fresh seawater every 1-2 hours to maintain temperature and freshness.

• Don’t let gas or oil touch the cuttings.

THANKYOU!