Coastal Aquaculture and Mariculture (2+1)

Unit 7 - Culture of Molluscs and Seaweeds

7.3.5. Culture systems

Porphyra (Nori) culture consists of placing bundles of twigs or rocks or concrete blocks for monospores to settle on. These are then transferred to shallow areas for development of thali to desired size. The most common method now is the use of nets with large mesh (15x15cm) and blinds made of 10x15 cm to collect spores and transfer to suitable areas for grow-out.

Blasting rocks surfaces or rocky reefs to expose for additional surface area for propagation is common practice, particularly for Laminaria and Undaria culture.

In commercial culture of Euchema in China, cuttings of plants are inserted in sub-littoral reefs by divers. A new method in recent years consists of fastening cuttings to coral branches with rubber strings and dropping them onto reefs. Divers rearrange them if required.

Raft and rack culture are followed in Japan and China. Laminaria is cultured on long lines in China.

In some Asian countries like the Philippines and Taiwan, Gracillaria and Caulerpa are grown in ponds following procedures common to fish culture, such as pond fertilization, water management and disease and pest control. Culture of these species is largely for industrial use.

Large scale seaweed culture for waste recycling and industrial uses is practiced in North America. Unattached masses of algae are grown in raceways and greenhouses flushed with seawater.