MUSSEL FARMING

MUSSEL FARMING The important genera -are Mytilus and Perna The major mussel producing countries - Spain, the Netherlands, France and Italy The species cultured :  Mytilus edulis – the Netherlands, France and Spain Mytilus galoprovincialis – Italy, Yugoslavia and Russia Mytilus smaragdinus = Perna viridis – the Philippines. Mytilus edulis Mytilus galoprovincialis Mytilus smaragdinus

Life History Mussels - filter feed on phytoplankton and suspended organic matter Reach sexual maturity in first year Spawn with rising temperature in the temperate region and almost throughout the year in tropics Sexes are separate, fertilization external

Larvae pass through trochophore and veliger stage, both are planktonic When they reach a shell length of 0.25 to 0.3mm, after 10-15 days, they attach to hard substratum such as rocks by means of byssus threads They can detach and reattach to different substrates They conglomerate and form thickly populated beds on rocks and other substratum mainly in the sub-tidal areas of the sea

Grow-out CMFRI – farming of green mussel Perna viridis - raft culture method Rafts - fabricated using wooden/bamboo poles tied together with nylon/coir ropes The poles are treated with coal tar to enhance their life Raft - 6x5 or 8x8m

Rafts mounted on 5 empty sealed drums of 200L capacity, painted with anti-corrosive paint Wooden planks are fixed on the raft to provide for working space Rafts are anchored in the protected areas of the sea using 3 iron anchors each weighing 100 kg at a depth ranging from 8-10m in the sea 1-1.5Km way from the shore Ropes with seed attached to them are suspended form the raft for growing to marketable size

Seed collection Seeds - from natural mussel beds Cleaned in seawater to remove mud and epifauna Size of the seed ranges from 20-30mm The seed are secured to nylon/coir ropes by enclosing them in a knitted cotton cloth of 25cm with and stitching it around the rope 500 to 700 juveniles are attached to each meter of the rope Diameter of the coir rope - 20-25mm; nylon rope -14mm Lengths of the ropes - 5-8mm Seeded ropes are attached 0.5 to 1m apart to the rafts suspended in the sea Seed mussels get attached to the ropes by byssus threads in 2-3 days and the cloth cover disintegrates in about 10 days

Growth and production The seeded mussels grow to 36g in 5 months Each rope 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 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 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 Should be manually cleaned periodically   Predation Predation by fish Rhabdosargus sarba Net enclosures around the rafts will eliminate predation. Fouling organisms Rhabdosargus sarba