The time of the introduction of P. gingivalis into our country is relatively short, and the units introduced by the broodstock are embarking on the broodstock breeding technique. The author is now on the production practice, summed up the desert spotted broodstock broodstock cultivation techniques are as follows: First, the source of broodstock broodstock There are two kinds of sources: First, from the natural sea area fishing, non-injury, to reach sexual maturity of wild adults, and then after artificial Domestication and cultivation; the second is to select normal, healthy, and fast-growing cultured adult fish from artificially cultivated populations. At present, no large-scale breeding of desert spotted gingiva has been conducted in China, and only a few units that cultivate broodstock rely on the import of wild adult fish of age 2 or older from the United States. After artificial domestication, they are used as broodstock. According to relevant reports, there are also some units that have introduced the newly hatched larvae in the United States or Japan for artificial breeding. After preparation, they are reserved for broodstock use. Second, broodstock domestication due to sudden changes in the environment, wild broodstock often can not adapt to the new environment, in the process of stocking will not feed for a long time, until the transition due to starvation, depletion of their own nutrients, so the domestication of wild broodstock, The first is artificially inducing its open intake. One method of domestication of broodstock is to feed live fish and shrimp first, and then use simulated live baits to induce broodstock to feed. It is worth noting that wild broodstock is more sensitive to human activities, so it must be avoided when artificially simulating lures. Excessive disturbing, so as not to cause the failure of broodstock domestication; another method that is relatively easy to obtain broiler domestication is to stock the wild broodstock that has been domesticated or the artificially cultivated broodstock and the undomesticated wild broodstock in the same cultivation pond and keep it normal. Feeding broodstock drives wild broodstock to feed, and conditional units can use the easily distinguishable turbot to drive wild broodstock to feed. Third, the feeding of broodstock 1. Feed selection Feed broodstock feed, you can use fresh or frozen, fresh and good wild fish, preferably fresh wild fish spawning, no matter what kind of bait fish, as long as Freshness, moderate size, broodstock can eat. Artificial feeding can be fed with compound feed, can be added in the feed 1% to 2% of
Vitamin E, feeding the amount of fish body weight of 2% to 3%, and when the broodstock is not feeding timely bait out, in general Feed once a day, in the winter when the water temperature is low, it can be fed once a day. 2. The broodstock cultivation water must be cleaned and the broodstock water must be clean. The dissolved oxygen should be above 4mg/L. The conditional units should also use sand filter water for the wintering of the fish (precise and spawning periods must use sand filter water). The water exchange capacity can be determined based on water quality, stocking density, etc. The most ideal farming method is water aquaculture, especially when the broodstock is used to increase water flow. The daily water exchange volume must be kept at least 8 cycles, and it must be maintained daily. More than 3 cycles. The broodstock incubation temperature is between 10°C and 24°C. 3. Stocking Density Broodstock stocking density is controlled at 2 tails/m2 to 3 tails/m2, with a male to female ratio of 1:1.5 to 2.5, and a male to female ratio of 1:3 is more ideal. 4. Cultivating the environment According to the author's observation, the mottled gingiva exhibit a certain degree of phototaxis in low light, but it prefers a slightly darker environment, and the broodstock shows a strong uneasiness toward pure white. For the method of shading broodstock broodstock breeding ponds, reference may be made to the brown brood broodstock breeding pond. Although wild broodstocks have been domesticated, wild broodstocks are still highly sensitive to human activities. They are particularly manifested in the presence of disturbed and frightened fish. They swim wildly in the bottom of the pool and often violently. The impact of the pool wall, resulting in damage to the fish, therefore, desert spot gingiva broodstock pool must be selected in a quiet place, and to avoid unnecessary human interference. Fourth, daily management of broodstock cultivation, we must have experienced professional and technical personnel responsible for, and at any time pay attention to the cultivation of personnel, the use of tools, broodstock, etc. for complete disinfection. The tools, thermometers, utensils, etc. used in broodstock breeding should not be mixed and sterilized before and after each use. No irrelevant personnel or outsiders are strictly prohibited from entering the broodstock breeding area. If it is a normal visit, visitors must change clothes, boots, etc., and undergo strict disinfection before entering the broodstock breeding area. During the visit, it is absolutely necessary to avoid appearing in cultivation. Standing on the top of the pool, walking around or putting his hand into the broodstock pond. Fifth, the temperature control technology of broodstock breeding 1. Technical summary The reproductive rhythm of fish and physiological factors and external environmental factors interact closely, light temperature control technology is the use of artificial changes in light, water temperature, running water, food abundance, etc. Means to control the rhythm of fish breeding methods. In the natural world, the gingival sexual maturity age is 2 years old. Spawning occurs more often in the autumn and winter when the water temperature declines. When the natural water temperature decreases from the high temperature period, the gonads develop rapidly, when the water temperature drops to Spawning begins at 18°C ​​to 19°C, and the spawning period occurs when the water temperature is 15°C to 18°C. Artificial light temperature control control, mainly from the adjustment of light time, water temperature and the use of sex hormones completed, using short light (9 to 10 hours of light per day) and low water temperature (16 °C ~ 17 °C) for artificial labor, or use of sex hormones ( GnRHa) for oxytocin production. 2. Example introduction According to relevant reports, the temperature and light control programs of the nursery of the Texas Marine Development Center in the United States of America are shown in the table below. After controlled by the temperature and light, the desert spot gingiva produced smoothly on February 1, 1998. Eggs are two months ahead of the natural population of natural sea areas in the same region. Mosquito lice Glurishment Temperature regulation example Date Light cycle (hours/day) Water temperature (°C) 1997/11/01 11 24 1997/11/07 11 23 1997/11/09 11 22 1997/11/11 11 21 1997/ 12/01 10 19 1998/01/11 9 18 1998/02/01 11 19 Desert spotted gingiva is similar to the brown gingivae in life style. The author combined the experience of culturing broodstock with brown gums to control the cold spot gingival lice. And gradually reduce the lighting time and light intensity, the specific method is: water temperature 18 °C fast cooling, until the synchronization with the outdoor water temperature, no heating; when the outdoor water temperature dropped to 10 °C, the water temperature in the preheated pool to 10 Use after °C. While cooling, a black curtain is placed over the brooding pond to control the light. The light control amplitude should not be too large, and the shading degree can be gradually increased from 5%/day to 10%/day until the shading rate is controlled at 85% to 90%. At this time, the illumination is equivalent to 8 hours/day to 9 hours/day. After the low-temperature wintering period, according to the actual production plan, the shading rate is gradually reduced 1.5 months before the planned spawning time, and finally controlled. About 60%. Beginning 0.5 months before spawning, enter the stage of rapid warming and ovulation, and increase the light time to 14 hours/day 10 days before spawning. Specifically, the temperature rise time can be determined according to the gonad development of the broodstock. If the gonad gonads are not ideally developed, the temperature can be raised one month before spawning. If the gonad gonads develop well, the temperature rises 0.5 months before spawning. . 3. Precautions When performing low-temperature control, it is necessary to prevent water temperature from being too low and causing regression of gonadal development.
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