Morphological Observation Of Embryonic Development And Effects Of Salinity On Growth Of False Clownfish Amphiprion Ocellaris

False clownfish is placed in Amphiprion ocellaris, Pomacentridae, Perciformes. It isa kind of common marine ornamental fish, hermaphrodite and cross-fertilization andwidespread in the sea of south China, Philippines and the western Pacific. False clownfishis a popular fish for ornamental fish enthusiasts for the bright colore, beautiful patternand lovely figure.The fish was collected from the wild as broodstock, and cultured to mature andspawned in artificial condition. The larval fish could be fed rotifer strengthened byunicellular algae chlorella spp. in the next day after hatching and developed intojuvenile at4~6days after hatching, newly hatched Artemia nauplii were supplied, fromthe10thday Artemia nauplii strengthen by chlorella spp. were supplied, then developedinto parr16~22days after hatching. The parrs could be fed by artificially madecompound feed at35~45days after hatching.The study was carried out to investigate the incubation period and the changes ofmorphological character during the embryonic development of Amphiprion ocellaris atwater temperature (26±1℃),salinity(28±1)in laboratory condition. It was found that theeggs belonged to the telolecithal and were subject to discoidal cleavage;The adhesivefertilized eggs, which were ellipsoidal, were2.0mm±0.1mm long and0.95mm±0.1mmin diameter;The process of embryonic development could be divided into ten stages:pre-cleavage stage, cleavage stage, blastula stage, gastrula stage, neurula stage, somitestage, turnover stage, angiogenesis stage, organ formation stage and hatching stage. Thecolor of the embryo changed gradually during the development procession, fromorange-yellow to claybank. The whole incubation period is about200h at watertemperature26℃.The effects of salinity on growth, feeding, food conversion rate (FCR), growthhormone and receptor mRNA leve of young Amphiprion ocellaris were studied. The results of the42thand70thday showed that there is no significant effect on the surviverate for young Amphiprion ocellaris at each salinity levels. The young Amphiprionocellaris had a highest growth at the25and30salinity levels, higher growth at20andlow growth at15and35. The feed conversion ratio is also higher at the25and30salinity levels and then reduced along the20,35,15salinity levels. The growth rate ofrelative body weight is conformed to this law. The molecular biology study began at the70thday, the result showed that the highest level of pituitary GHmRNA was at salinity15and higher at35, the lowest level was at salinity20,30,35. The highest level ofhepar (liver) GHR1mRNA was at salinity20,25,30and higher at35, the lowest levelwas at salinity15. The highest level of hepar GHR2mRNA was at salinity25and higherat20, the lowest level was at salinity15,30,35. The expression of GHR1mRNA andGHR2mRNA positively correlated with growth.The most suitable salinity range is25~35.