Studies on induced maturation, spawning and larval settlement in green mussel Perna viridis (Linnaeus, 1758)

摘要

In the green mussel Perna viridis (Linnaeus, 1758), studies were undertaken on theudinduced maturation, spawning, larval rearing and settlement.udPerna viridis broodstock could be conditioned or induced to mature out of the spawningudseason by maintaining them at 23 ± 1 • C, at > 30 ppt salinity, pH 7.5 - 8.2 and fed withudChaetoceros calcitrans at a cell concentration of lx 10 5 ml-1 fortified with 700 I.U. cod liver oil @ud1 I animal-1day-1 in two installments for 15 and 32 days respectively.udAll increase of 5 • C form the ambient water temperature at a salinity> 25 ppt and pH 7 -ud8.2 with an addition of male or female gametes was able to induce 100 % spawning in 1 -2 hoursudin P. viridis. No sex wise pattem was observed. None of the commonly used chemicals likeudHydrogen peroxide or Serotonin was able to elicit a full spawning response.udStudies on the effect of Physico - chemical parameters for larval rearing of P. viridisudshowed that a temperature of 29 • C - 31 • C at high salinity > 30 ppt with 50 ppmudChloramphenicol antibiotic at pH 8.2, with moderate aeration and fed with lsochrysis galbana, asudthe best for optimum growth, percentage survival and settlement of spat.udSettlement preference indicated clearly that primary settling larvae required filamentousudsubstrates and among these byssus threads was the best substrate even though presence ofudadult mussels significantly attracted more mussels.than byssal threads. High temperature 31• C,udmoderate aeration, salinity of 25 - 38 ppt, pH 7 - 8 was optimum for larval settlement.udAmong the various chemicals tried L-DOPA gave the best results with 100 % settlementudobserved in 5 hours at 2.5 x 10 -7 M.udRemote setting was also successfully done with larvae transported in ambient moistudcondition. A 24 hour transportation period did not significantly affect the percentage of P. viridisudlarval survival or settlement