The parent fish rearing method of Cynoglossus semilaevis
The present invention relates to the artificial fecundation method of a kind of Soleidae fish, specifically, is a kind of artificial fecundation method of Cynoglossus semilaevis.Belong to the aquaculture field in the ocean engineering.
Cynoglossus semilaevis (Cynoglossus semilaevis Gunther) belongs to Pleuronectiformes, Cynoglossidae.Owing to fine and tender taste, delicious flavour are liked by consumers in general, be the very high famous and precious fingerling of a kind of economic worth.Cynoglossus semilaevis is lived all the year round and is perched the greater coasting area in China, and wide warm, the wide salt of tool, the characteristics that the food level is low are one of fingerlings that are considered to desirable breed, propagation, and the production of its scale has been subjected to the very big attention of social each side.
The reproductive habit of Cynoglossus semilaevis has following main feature: at first, in Various Seasonal, the female and male ratio of a given area Cynoglossus semilaevis natural population changes greatly.Under the general situation, the female and male ratio of colony is: ♀: ♂=61: 39.Female and male ratio also has obvious variation with the degree that sexual gland is grown.Before laying eggs (mid-August before), the raun in the reproduction colony has comparative advantage, and property is than being ♀: ♂=4: 1; After mid-August, milter is increased gradually, and female-male proportion is ♀: ♂=2: 1; Early September, the ontogeny gonad maturity, between the whole egg-laying period, raun accounts for 55%, and milter accounts for 45%, and these characteristics are more obvious than what show in other marine products bony fishes.Second individual size of characteristics male and female has significant difference, and full ripe individuality can significantly be divided into female, male two individual long groups, the long 390mm that surpasses of female fish length group body; Male body length is from 180mm-380mm.In whole spawning colony, raun reaches 735mm the most substantially; The long 490mm of corpusculum; Average 523mm, milter is the longest to be 420mm; Corpusculum is long only 198mm, the long 280mm of average body.The 3rd characteristics male and female sexual gland difference great disparity: the ovary of Cynoglossus semilaevis is very flourishing, and spermary is extremely undeveloped.The raun fish brood amount is very high, the individuality of the long 560-700m of body, and the ovum amount is up to ten thousand of 76-250, and most individual fish brood amounts are about 1,500,000.The difference of male and female sexual gland causes natural waters ovum fertilization rate low excessively, the lethality height.In addition, break away from natural environment without such fingerling of raising and train after the time-to-live shorter, the accumulating of incompatibility live body.
In addition, Cynoglossus semilaevis is not strong at the natural waters sociability, and also cluster not between the egg-laying period causes the spawning ground to disperse relatively.
Though domestic and international many scientific research institutions, universities and colleges, business unit etc. repeatedly carried out the Cynoglossus semilaevis artificial propagation test research of different scales and degree; all because of to knowledge of biological deficiencies such as the ecology of this fish, physiology; do not obtain satisfied result, the large-scale production of Cynoglossus semilaevis is unable to reach always.
Summary of the invention
Technical problem to be solved by this invention provides a kind of parent fish rearing method of Cynoglossus semilaevis, solves the problem of raising and train of parent population by the hydrological environment factor of controlling parent fish rearing; Solve the parent fish live through the winter problem by control parent population growing environment condition; By grasping illumination, water temperature variation solution parent population gonad development problem.
In order to address the above problem, the present invention has adopted following technical scheme.
A kind of parent fish rearing method of Cynoglossus semilaevis is characterized in that: between parent population culture period in early stage, envirment factor comprises: water temperature 26.2-18.4 ℃; Salinity 26.20-30.60 ‰; Ph7.7-8.6; Dissolved oxygen 6.5-9.5mg/l; The property than comparing=1: 3 for male and female;
Parent fish live through the winter, when promptly the seawater natural temperature was below 12 ℃: water was the mixing water of subsurface brine and fresh water, the water quality factor scope is reached: salinity 28.55-29.15 ‰, PH7.6, dissolved oxygen 8mg/l, temperature 15.3-16.8 ℃;
During the parent population gonad development: water temperature is brought up to 24 ℃ gradually by 18 ℃, and every day, intensification was no more than 0.2 ℃, and 60 days is a temperature control cycle; Light application time was brought up to 12 hours/day gradually by 6 hours/day, prolonged light application time every day and was no more than 72 minutes, and 5 days is a control photoperiod, and intensity of illumination is being 5001ux.
The value of water temperature, salinity, PH, dissolved oxygen 8mg/l, property ratio all is keys of the present invention, and experimental study obtains through several times.It is on the low side that water temperature is crossed low parent population food ration, and water temperature is too high can to induce an illness again.Salinity is lower than 12 ‰ parent populations can not survive, too high then poor growth.The too low rate height of having an attack of one's old illness of pH value, too high parent population survival rate reduces again.Dissolved oxygen is lower than the lower limit parent population and is in disadvantageous anaerobic condition, and not only reproductive-cost is too high greater than higher limit, and parent population to get the probability of bubble illness higher.
Temperature control during the parent population gonad development, control light technology are the another crucial points of creating of the present invention, the change modeling gradually of temperature and light application time natural environmental condition, be more suitable for the breeding of such fingerling.Temperature and light application time amplitude of fluctuation also are to determine through the several times experimental study.
By implementing this programme, parent population gonadal maturation, the obvious projection of belly; Comfort the protruding place of the outside of belly with have gentle hands, feel that obviously sexual gland is soft state, 100% parent population gonad maturity.Reach developmental level nearly 4 months under the natural conditions with 50 days times; Guarantee 100% normal development of raun sexual gland and spawning and fertilization.
Repeated the parent fish live through the winter result of the test in 2 years and show that the parent fish live through the winter survival rate is 100%.Parent population is in a good state of health, and body colour is darker than natural waters parent population, does not find any disease and parasite phenomenon.
(6.0 * 4.0 * 1.5m) as parent fish rearing and wintering pond to utilize general cement pit.Lay the silt of anticipating at the bottom of the pond, form artificial seabed.Silt is through tedding, sieving, and husky mud ratio is 3: 1, thick 20-30cm.Chi Dipaishuikongchu installs a flow regulator and water circulation pipeline.The double-deck internal diameter of pipeline is respectively 20cm and 14cm, high 165cm.Flow rate of water flow is adjusted in the 20-48L/ branch scope.Before parent population goes into the pond, soak, wash till pond water PH reduces to below 8.6.
During the parent fish rearing, the inflation of row discontinuity.Gas stone is distributed in near-bottom, in order to avoid when inflation stirred silt.All other envirment factors comprise: water temperature 26.2-18.4 ℃; Salinity 26.20-30.60 ‰; Ph 7.7-8.6; Dissolved oxygen 6.5-9.5mg/l; It is 4-6 tail/pond that parent population is thrown in density, and property is than being ♀: ♂=1: 3.
In the parent population management process, the every envirment factor of (1) periodic monitor is kept every factor in the suitableeest scope.(2) keep cleaning water quality.Keep circulating water body.Every day, rate of water exchange was more than 100%.Keep water at the bottom of seeing the pond clearly, to be advisable, remove residual bait, dirt, remove dead fish.Check the parent population survival rate before fresh seawater is injected, observe the gonad development degree and the situation and carry out record of ingesting.(3) guarantee sufficient bait supply.Bait throwing in every day 2 times.Feeding volume is about the 3-5% of parent population body weight.Food species one clam worm, mantis shrimp and variegated clam meat are main, and small fish takes second place.The parent population of initial acquisition is refused feed usually, and indivedual parent population food refusals are until hungry to death.The big more food refusal duration of individuality is long more, the male length of female parent population food refusal time ratio.It is more than daytime to ingest night.
In order to protect the precious fingerling resource of Cynoglossus semilaevis and to obtain sufficient fertilized egg, we have carried out the test of Cynoglossus semilaevis parent fish live through the winter.Further explore this fingerling gonad development rule and the mechanism of laying eggs in the process of the test.
In Bohai Sea Gulf, mid-November, water temperature is reduced to below 12 ℃, and parent population begins to change over to the phase of surviving the winter.
The parent fish live through the winter water is subsurface brine (salinity 84 ‰, temperature 16.0-18.0 a ℃; PH7.6) with the mixing water of fresh water, the water quality factor scope is reached: salinity 28.55-29.15 ‰, PH7.6, dissolved oxygen 8mg/l, temperature 15.3-16.8 ℃.
The beginning of surviving the winter adopts natural sea-water to cultivate the parent population that survives the winter.In the incubation, strengthen the proportioning of the artificial mixing water of bittern fresh water gradually.Behind the two weeks, cultivate the halogen fresh water that water all is replaced with artificial mixing.The wintering pond water temperature maintains in the 15.3-16.8 ℃ of scope.In last ten-days period February in next year, along with the rise of temperature, the wintering pond water temperature is heightened gradually.When marine water temperature rose to 12.0 ℃, parent fish rearing water strengthened the nature seawater ratio gradually till whole waters transfer natural sea-water to.
The inflation of parent fish live through the winter pond is the discontinuity inflation, morning every day, ventilation in evening 1 hour.Changed water in 2-3 days one time.When changing water, observe parent population activity, health status, the situation of ingesting.In time remove residual bait and dirt, keep water cleaning.Regularly throw in 1-2ppm antibiotic, occur with anti-communicable disease.
Survive the winter parent population bait to freeze variegated clam, and clam worm is secondary with freezing trash fish.Feeding volume is the 2-3% of parent population body weight.
Selected male and female parent population, raise together with in proportion in a cement pit, through meticulous nursing fattening after a while, after having reached perfect condition, with reference to the basic law of this fish at the natural waters gonad development, relevant biological property, it is unique to develop a cover, is different from temperature control, control light method that he plants the flatfish class.Based on temperature, illumination is auxilliary, and concrete measure is: water temperature is brought up to 24 ℃ gradually by 18 ℃, and every day, intensification was no more than 0.2 ℃, and 60 days is a temperature control cycle; Light application time was brought up to 12 hours/day gradually by 6 hours/day, prolonged light application time every day and was no more than 72 minutes, and 5 days is a control photoperiod.This technical essential comprises: determine the regulation and control start-up point with gonad development period and temperature; The light of order gradual change, warm processing parameter and processing time-histories.