Artificial Propagation And Fry Rearing Of Barfin Flounder (Verasper Moseri)

Barfin flounder(Verasper moseri Jordan et Gilbert),commonly known as black flounder,plaice and Morocco-Star,is affiliated with the Pleuronectiformes (Pleuronecti-tormes),Pleuronectidae(Pleuronectidae).It is a species of cold temperature fish located in the bottom of north-west Pacific and it is mainly in the Sea of Okhotsk,the northwest sea area of Japan,the east and southwest sea area of the Korean Peninsula,and Yellow Sea and Bohai Sea areas of China.Barfin flounder is succulent and delicious taste and is the rare aquaculture species of high commercial value.Barfin flounder in northern China,is only scattered,its amount of natural resources is very small,particularly natural fry is shortage,which restrict the development of aquaculture industry.At present,the domestic aquaculture industry is committed to technique of the artificial breeding of barfin flounder,this species is about to be a new type of flounder for cultivating in recent years.Since we introduced the artificial seeds of barfin flounder from Japan in November 2004,the domestication of the factory,cultivating the middle,as well as develop and promote people familiar types of fish and other studies have made remarkable achievements in scientific research.However,it is need to be further perfected in many links.The cultivation of barfin flounder seed,is an important way to change the composition of culture species,modify the structure of supply and demand,and stimulate the development of marine fish breeding.This article carried out a series of research in many areas,such as the introduction of the fry of barfin flounder,domestication and cultivation,growth and transformation of eco-efficiency,parental fish cultivation, artificial insemination and incubation,seed rearing and artificially induced gynogenesis.First of all,we determined growth and ecological conversion efficiency after the first anniversary of the introduction of seed.The results showed that the average value of growth in the body length of barfin flounder was 0.55mm,the fastest growth is 1.13mm,the average growth of daily weight gained 2.33g and the largest daily growth gained 4.63g.The body length and weight appeared exponential relation: W=10-5L3.0226,r=0.9893.Eco-efficiency of the annual fluctuations was in the range of 34.16-91.07%.Environment-induced and nutritional fortifications were applied to 597parental fish,including 457 male and 140 female.After three months of intensive training,85%female and 95%male achieved sexual maturity.From 2008 February 16 to March 31,we collected eggs 16 times,about 12000ml,and obtained 700,000 hatched larvae.Fertilization rate ranged from 30.0%to 86.0%and hatching rate ranged from 29.0%to 85.0%.During the process of seed rearing,water temperature was 10-17℃,salinity was 30-32‰,pH was 8.0-8.2,the volume of air was 20L/m3 per hour,gradually increased to 60L/m3 per hour in 5 days,the amont of change water gradually.increased from 10%to 50%per day in 15 days,and reached 150%along with the growth of the larvae at last.S-rotifer→Artemia nauplii→Formulated Diets were used during the fry culturation.In the induction of heterogeneous gynogenesis test,first of all we find out that ultraviolet radiation for 210 s is a suitable time of inactivating sperm,genetic material of sperm was completely inactivated,and fertilized at the same time had the highest hatching rate for 30.64 percent.Our results of inactivated duration was similar to the results of Mori, which reported inactivated dose in the barfin flounder is longer than that of the Japanese flounder(Paralichthys olivaceus),but lower than other flounders.