Coastal Aquaculture and Mariculture (2+1)

Unit 7 - Culture of Molluscs and Seaweeds

7.2.3. Growth and production

The seeded mussels grow to 36g in 5 months. Each rope will yield about 5.1-12.3Kg/m. 100 ropes of 6m length in a raft of 8x8m will yield 4800Kg per raft assuming an average production of 8Kg per m of the rope. It works out to 150 tonnes per hectare in 5 months.Cultured mussel have better meat yield (35-40%) compared to wild mussels (27-32).

Management of rafts

• Collected mussels should be seeded within 24h.
• Periodic inspection of rafts to detect leakage in floats, damage to rafts or ropes
• Farm area should be demarcated with lights and flags to avoid damage by fishing boats.
• Periodical cleaning and thinning of mussels to improve growth rates

Fouling organisms
Fouling is a serious problem in mussel farming. Barnacles attach themselves to ropes and mussels with 30 days of seeding the ropes. More fouling takes place in the upper 2 m of the rope. Heavy fouling by a bivalve Mytilaster arculatula takes place in the months of November and December. Other fouling organisms are tubiculous polychaetes, Ascidians, Cnidarians and Bryozoans. Fouling organisms should be manually cleaned periodically to remove competition for food and space and to improve the growth mussels.
Predation
Predation by fish Rhabdosargus sarba has also been reported. Net enclosures around the rafts will eliminate predation.