Commercial farming of mussel is dependent on the availability of seed. The natural spat fall 

is considered to be the primary source of seed. Although technology for production of mussel 

seed in hatchery has been perfected but it is not economically viable for commercial farming

Velayudhan, T S

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Mussel seed resources of India and seeding methodsT.S. VelajTidhanM o l l u s > ; a n  r is h c r i . . - . s  D i v i s i o n .  C M l - R I .  K o c h i .  P i n  6 8 2 0 1 8 . .  E m a i l :  t s v c l y u d h f ^ y a h o o . cIn troduc tion1 lic m ussel seed se lt lem enl intensity atid pattern may vary from y ear  to  year according to changcs in environm enta l conditions which in tu rn  influences the spaw ning  o f  mussels.S p a t  collcction m eth o d sC om m ercial la rm ing  o f  m ussel is dependent on the availability o f  seed. T he  natural spat fall is considered to be (he prim aiy  source o f  seed. Although technology for production o f  mussel seed in hatchciy has been perfected but it is not econom ically  viable for commercial fanning.A  w ide  variety o f  spat co llectors like trilled ropes, ro o f  tiies, old fish net, shading materials, bam boo  splits e tc are u sed  for collection o f  spat. T he  selection o f  the appropria te  material as spat collector depends on the efficiency, local availability, durability and cost o f  the material.I he  e l l ic ien cy  o f  spat co llection depends on forecasting  the accura te  t im e  o f  spat fall. The spat fall can be cxpec ted  w hen  the gonad  r ipeness  corresponding w ith  an ex tended dry period broken by a spell o f  heavy rains. U sually  the spat fall occurs during  the months o f  Ju ly-A ugust. Spat co llec to rs  are suspended at least tw o w eeks prior to  spawning. The spat co llection  period can  be decided  by putting tes t pane ls  an d  plankton sam pling  in the natural spa t co llection sites and daily  examination o f  spa t collectors for the  highest num ber o f  m etam orphosed  ped ive iige r  on the test collectors. I f  the test co llectors taken daily  and favourab le  num ber o f  spa t are there, then im m edia te  suspension  o f  large num ber o f  spat co llec to rs  for m ax im um  spa t collection from th e  spat co llection cen tres  can be done. In lh a i la n d  this m ethod is fo llow ed as a festival w here  in all farmers pu t the  spat collectors in the  setting  areas.Table. 1. M onth-w ise  m ussel seed ing  and farming activities for different m an lim c  states o f lnd ia .0 N DH arv es tTable 2 .Slate wise mussel seed resourceM u sse l  Seed  R eso u rcesS la te A rea Biom ass Avg.no.Length(Sq .m ) (0 o f s e e d /S q M range  (m m )O rissa 61092 44,2 4515-117A ndam an  &  Nicobar 1980 14.2 103 5 -2 0 1Kerala 5889820 8934 15821 6 - 2 0K arna taka 877695 1746 83215-34Tamil Nadu 107706 1508 50023-112Pondicherry 116200 37 5252 0 - 1 1 2A ndhra  Pradesh 21714 6 123 7 - 1 9 7M aharashtra  &  Goa 7230 2849 7441 3 - 4 0Gujarat 2000 0.03 7 8 2 - 1 3 4T O T A L 7083437 15138.4 7-158215-201Fig  1. 'I'lie seed setllenicm on  vclon scrccn, frilled ny lon  rope  and old fish ne t w ere 5237 ,2287  and 675 n o s  per  50cm- rcspcclivcly. T he  num ber o f  spat (avg. length  2-9mm, avg. w t 0 .02 g) settled w as  h ighest,  20614  nos per  2500cm - on the tiles.Seed on  tilesM ussel spat on velon screen Spat on frilled ny lon  materialS eed in gS eeds collected  from the natural bed or spat co llectors are thoroughly c lcancd  o f f  cpifauna and o the r  organisms- T he  ideal s ize o f  the seed for seed ing  is I5-25m m , w ith  l -2 g  weight per  Im length  rope.T he  detachcd  m ussel seed a rc  seeded on  to  the  cu lture  ropes. T he  length o f  the seeding rope depends  on  the depth  o f  cu ltu re  area. T he  seed a re  p laced  on a cotton m osquito  netting and stitched tightly around the cu lture  rope. The cloth will disintegrate w ith  in 2-3 days and by this lime the seed  gets attached to  the  culture rope b y  m ean s  o f  byssus thread. For avoiding slippage o f  m ussels , knots are m ade  o r  10-15 cm length o r  b am b o o  pegs  are inserted horizontally  in between the tw ists  o f  the seeded ropes  at regular intervals o f  25cm . O n  an average  1 kg  o f  seed  is seeded on  to  a culture rope o f  im  length.T he  advantage  o f  spat transfer  technique is that cu ltu rc  can  be  done  in areas  other than natural spat fall. The spat will rem ain  live for l o r  2  days i f  k e p t  cool and damp. This facilitates the transfer o f  seed  to  new culture areas.The M olluscan  Fisheries D ivision o f  C M FR l, C ochin  has designed a semi aulom alcd seeding m achine. A  biodegradable wrapping material (collon m osquito  net) w as stitched into tubes o f  20 lo 25 cm  width  and 1,25m length. During seeding the nylon rope was placcd witliin the prc-stitched tube and filled with m ussel seed. The ends were tied and these seeded ropes were suspended from the  rack. This m ethod resulted in reducing the m anpow er needed for seeding.I 'ig 2. Semi automated Seeding machine

Mussel seed resources of India and seeding methods

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Mussel seed resources of India and seeding methods

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