Marine ornamental fishes have gained much

popularity all over the world. India is endowed

with a variety of marine ornamental fishes

distributed in our coral reef areas which offers

vast scope for the development of a domestic

as well as export trad

Krishnan, L

Madhu, K

Madhu, Rema

Sasidharan, C S

Venugopal, K M

CMFRI Digital Repository

TECHNICAL AND EXTENSION SERIESCENTRAL MARINE FISHERIES RESEARCH INSTITUTECOCHIN, INDIA(INDIAN COUNCIL OF AGRICULTURAL RESEARCH)ISSN 0254-380 XMARINE  FISHERIESINFORMATION  SERVICENo. 188 April, May, June, 2006Mar. Fish. Infor. Serv., T&E Ser., No. 188, 2006 1Spawning and larval rearing of Amphiprion ocellarisunder captive condition.1169Marine ornamental fishes have gained muchpopularity all over the world. India is endowedwith a variety of marine ornamental fishesdistributed in our coral reef areas which offersvast scope for the development of a domesticas well as export trade.Clown fishes or sea anemone fishesAmong the different marine ornamental fishes,the genera Amphiprion and Premnasbelonging to the family Pomacentridae andsub family Amphiprioninae commonly knownas clown fishes or sea anemone fishes are themost popular attractions all over the worldbecause of their tiny size, hardiness, attractivecolour features, peaceful nature, highadaptability to live in captivity, acceptabilityof artificial diet and their fascinating displaybehaviour and symbiotic relationship with thesea anemones. But most of the traded saltwater ornamental fishes are being collectedfrom the wild and hence there is a greatconcern regarding the depletion of the stocksdue to over expoitation as well as thedestruction of reef habitat and damagingcollection methods. Hence investigationsshould be focused on the development ofhatchery technology and the production canlead to hatchery produced ornamental fishestrade of marine which is long term sustainable.Efforts made in this line in CMFRI, Kochiwhich resulted in the successful breeding andmass scale production of false clownAmphiprion ocellaris, one of the mostdemanded species among the clown fishes.Pair formationIn order to make breeding pairs, many socialgroups of A. ocellaris were collected fromthe wild and transported to the laboratory inlive condition. During transportation, the fishesand sea anemones were kept in separateplastic transportation bags. Five fishes of eachsex of different size groups were stockedtogether along with single sea anemone (H.magnifica) in 500-liter FRP tanks fitted withbiological filter in order to reduce the level ofaggressive behaviour. The pair formationtanks were maintained in the hatchery wherean incident light intensity of 2500 to 3000 luxwas available as the sea anemones requiresunlight for its better survival under labortorycondition. The fishes and anemones were fedtwo times per day with wet feeds such as meatof shrimp, mussel and clam at the rate of 15%of their body weight and live feeds likeMar. Fish. Infor. Serv., T&E Ser., No. 188, 2006 2Brachionus plicatilis and Artemia nauplii.In all the tanks, the range of environmentalparameters maintained were : temperature :26 to 29O C, salinity : 33 to 36 ppt, dissolvedoxygen : 4.6 to 6.2 ml/l and pH : 8.1 to 8.9After a period of 3 to 4 months rearing, onepair grew ahead of others in each tank andbecame the spawning pair and the functionalfemale and male (the two largest specimensof the colony) live together as pairs in whichthe female dominates male and the sub adultsare dominated both by the female and male.The standard length of the female variedbetween 89 to 100 mm (presumptive female)and that of male varied between 40 to 60 mm(presumptive male).Brood stock development andmaintenanceThe pairs developed through pair formationwas then transferred to seperate glass aquariato develop as brook stock in 500 literscapacity tank along with single befitting hostanemone. Depending upon the productioncapacity and seed demand, several pairs canbe maintained for commercial hatcheries. Thebroodstocks were fed with wet feeds suchas mussel meat and shrimp, clam meat, fishegg mass and also provided formulated feedsenriched with vitamins, minerals and algalpowder at the rate of 10% of their body weightand supplied at an interval of every 3 hrsduring day time, whereas in the night, theywere fed with live feeds such as rotifers andArtemia nauplii at the rate of 3,5 Nos./mlrespectively after enriching the same with amixed culture of micro algae such asNannochloropsis oculata, Pavlova lutheri,Isochrysis galbana, Dicrateria inornata,Chromulina pleoides, Cholrella marina andChaetoceros gracilis which apparentlyimproved egg quality and hatchability than thebrooders fed with non enriched live feeds.The temperature in all the breeding tanks weremaintained between 26 to 29OC, and level ofdissolved oxygen (4.8 to 6.3ml/l), pH (8.0 to8.9), salinity (32 to 36 ppt) and the water isrecirculated to ensure water movement andprovided good water quality with the aid of aspecially devised filter system during theperiod of rearing. 25% of the water wasexchanged weekly to avoid stress like a rapidincrease in plasma corticol concentration,depression of gonadal streroidogenesis, andsubsequent development of gonadal atresia.Each brood stock tank was provided withtiles or earthen pots for egg deposition so thatthe substratum itself along with egg could betransferred to hatching tank and it also helpedto minimize the mechanical injury which mayhappen during transferring of newly hatchedMar. Fish. Infor. Serv., T&E Ser., No. 188, 2006 3larvae to the larval rearing set up.BreedingEach pair started  breeding within a period of4 to 6 months rearing under captive condition.Few days prior to spawning, the male selecteda suitable site near to sea anemone for layingthe egg and cleared algae and debris with itsmouth. On the day of spawing both the parentsspent considerable time for the celaning of sitewhich indicated that spawning may occurwithin few hours. Under laboratory condition,the spawning was noticed between 0500 to1530 hrs during day time and the spawninglasted for one to one and a half hour. Eachfemale laid 300 to 1000 capsule shaped eggsat every 12 to 15 days interval depending onthe size of fish and previous experience. Theegg size ranged between  1.5  to 3.0 mm inlength with a width of 0.8 to 1.84  mm andadhered  to the sides of earthen pot with stalk.An average of two spawnings per lunar monthper pair resulting in an estimated annualfecundity of 24000 eggs per breeding pair peryear can be obtained under laboratorycondition.Parental care and eggs developmentsAs parental care is inevitable for hatching theparents were allowed to remain in the parentaltank itself till hatching. During incubationperiod, both the parents carefully looked afterthe eggs during day time and it involved twobasic activities viz. fanning by fluttering thepectoral fins and mouthing to remove the deador weakened eggs and dust particles, but nonocturnal care was noticed. The newlyspawned eggs were white in colour for initialtwo days and as the embryo developed, theseturned to black on 3 rd to 6 th day and laterturned to silvery on 7th to 8th day ofincubation. At this stage the glowing eyes ofthe developing larvae inside the egg capsulewas clearly visible when viewed from a shortdistance. Male asumed nearly allresponsibilities of caring for the eggs and spenta higher percentage of time at the nest thanthe females, which increased gradually up to70% of time as the day of hatchlingapproached. When incubated at a watertemperature range of 27 to 29O C, thehatching emerged on 8th day of incubationand peak hatching took place shortly aftersunset.Egg hatching and larval rearingOn the expected day of hatching, two hoursbefore sunset, the parents and eggs along withsubstratum were transferred from the parentaltank to hatching tanks (100 liters) which wereprovided with complete darkness foraccelerating the hatching. The larvae brokeMar. Fish. Infor. Serv., T&E Ser., No. 188, 2006 4the egg capsule and the hatchlings emergedtail first and the hatching occurred soon aftersunset and the peak hatching took placebetween 1900  to 2200 hrs under darkness.Soon after hatching, the parents weretransferred to breeding tank. The newlyhatched larvae measured 3 to 4mm in lengthand each had a transparent body, large eyes,visible mouth, and a small yolk sac andremained at the bottom of the tank for a fewseconds and soon after became freeswimming. The mouth gape of the newlyhatched larvae measured 170 to 210µ. Thelarval rearing was carried out under greenwater system . The larvae were initially fedwith micro algae and later on they were alsofed with super small rotifer B. rotundiformisand newly hatched Artemia nauplii. First dayonwards the larvae were fed with mixedculture of microalgae and rotifer B.rotundifrmis (6 to 8 nos/ml) upto 8th day.From 9th day onwards the larvae wereweaned onto newly hatched Artemia nauplii(4 to 6 nos/ml) along with rotifer and mixedculture of micro algae and on 12th day to 17thday of post hatch the larvae were fed withnewly hatched Artemia nauplii. The first signof pigmentation appeared on 9th to 10th dayof post hatch. At 15 to 17th day of post hatch,most of the fry resembled juvenile adult fishand began to shift from partially pelagic toepibenthic (Fig. 1) and started eating mincedshrimp, fish flesh, mussel meat, clam meat andformulated diets. The range of environmentalparameters maintained were salinity (32 toFig. 1 Juveniles of Amphiprion ocellaris(15 days old) settling in sea anemoneHeteractis magnifica35ppt), temperature (24 to 28OC), dissolvedoxygen (5.3 to 6.8 ml/1) and pH (8.1 to 8.9)With this feeding schedule and environmentalconditions, the larval survival and growthwere hastened and 90 to 95% survival wasobtained at each spawning. The juveniles werefed with different wet feeds at the rate 20%of the body weight and attained marketablesize within three to 4 months. Culling of thejuveniles were started from 40mm sizeonwards to reduce aggressiveness andcompetition for food and space. Twenty fiveto 50 numbers of juveniles (50 mm size) canMar. Fish. Infor. Serv., T&E Ser., No. 188, 2006 5be stocked in a 250 litre FRP or glass tankwith a single host anemone (200 to 300 mmdia) to ensure maximum survivability (Fig. 2).the larval rearing was the "head-buttingsyndrome". In order to reduce this, measureshave been taken to avoid reflection of lightinside the tank and a low intensity light (15W)has been providedd to the larvae during dayand night to locate the feed and it also helpedto keep the larvae swimming towards thesurface at night rather than sinking to thebottom which otherwise show high overnightmortality. It was found that larval period from5th and 8th day of post hatch was criticalperiod and mortality may occur during thisperiod due to change in feeding behaviour.At this stage provision of nutritionally adequatefood in optimum quantity is of vital importanceto overcome the critical stage. Throughvarious experimental tarils all these hurdleshave now been overcome and a productionprotocol has been developed for the massscale production of A. ocellaris under captiveconditions.Prepared by : K. Madhu, Rema Madhu,L. Krishnan, C.S. Sasidharan and K.M.Venugopalan, CMFRI, KochiFig. 2 Three months old hatchery producedjuveniles of Amphiprion ocellarisThe major technological hurdles of anemonefish breeding is the selection of suitablebreeding pairs. As these fishes are protandrichermaphrodites, maintaining good waterquality and ensuring slight water circulation isalso found very essential for better survivabilityof larvae. For this , aeration was provided atfour corners of the tank through the PVCcolumns covered with 200 micron bolting silkcloth to avoid thrashing of delicate larvae. Oneof the critical problems encounterred duringGillnet and hook & line fishing off Mangalore1170Fishing using gillnets and hooks and line havebeen in vogue along Mangalore coast since along time. These fishing practices are verypopular and found to be lucrative alongcoastal Karnataka. Fishing using gillnets andhooks and line has so far been operated only

Spawning and larval rearing of Amphiprion ocellaris

under captive condition

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Spawning and larval rearing of Amphiprion ocellaris under captive condition

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