Out of season California perch breeding hot, the mortality rate after the seedling morbidity is as high as 90%! Standard seedling high yield strategy please close!
In recent years, having the "fifth home fish" said the California bass more and more fire, a lot of farmers turn to raise this fish, to earn the life of the "first bucket of gold". At present, it is the off-season perch breeding season in California, and farmers in many places are enthusiastic about seedling casting. How to deal with the disease in the seedling stage?
Chengdu area California sea bass consumption is big, the price is the highest all the year round also, this makes chengdu develops the southwest area California sea bass to raise seedling concentration, perennial supply cloud expensive sichuan and chongqing of all kinds of specifications seedling. But in the past two years, the success rate of California perch seedlings is getting lower and lower, and this year is a large number of ponds, the success rate is less than 5%. According to the repeated follow-up investigation, it was found that the seedling loss is mainly the emergence of "dragging stool", "ripe body", "circling" and other symptoms, the onset of these symptoms are different, the following to comb for you.
When the fish fry started to get sick, they first appeared slight dragging symptoms, and then gathered on the water surface and stopped feeding. 2 days later, the symptoms of "ripe body" will appear, resulting in a large number of deaths; Then appear circling symptoms, at this time fry death decreased, gradually began to feed. Seedling onset can be roughly divided into three stages, each stage of the main symptoms are dragging stool, ripe body and swirling.
The stage in which the symptoms of "dragging stool" predominate
Fry drag stool, abdomen appeared "a little red", anal swelling, serious light extrusion anal flaxen liquid outflow. In turn (blunt frozen insect), the low pressure hot weather or mutation, lack of oxygen to return at the end of, after feeding worry too full to outbreaks, this period should be more than a small meal feeding (about 3 hours advisable) during the day, use low protein feed fermentation feed, splashed outside of avoid by all means, not heavy use of disinfectants, antibiotics, can accentuate, accelerate the course of development, and even death directly.
"Familiar body" symptoms of the main stage
Cooked body symptom is mainly caused by slug virus infection, like boiled fish body, tail, and even the whole body color white handle, the onset of specification 3-9 to give priority to, the smaller the specification of the pond incidence after the higher mortality, disease buoyancy, the stagnation of the water, fish swim slowly or "dead", after the death of most heavy in the bottom of the pond, after the mortality rate is as high as 90% above, And most of the dead are the larger fry in the pond.
Investigation and analysis of weather change, bubble disease, overfeeding, insecticide and algae killing, cross pond and other operations easily lead to stress of fish fry, infection of pathogenic bacteria. During this period, to stop feeding, "activating" 1 package/mu and "base oxygen adding 1kg" 3 mu/mu can be used to stabilize water quality and reduce stress. Herbals, povidone iodine, can actually aggravate death, so don't rush into medication and wait for the "spinning" symptoms to appear.
"Circling" is a symptomatic stage
The pathogen of this stage is also the rhabavirus, the fish with black body, slow reaction and slow swim to the side; In the surface of the spiral "circling", the general onset of 2-3 days, death can drop from tens of thousands of tail to hundreds of tail, after the death of dozens of tail every day, most of them die of exhaustion and circling, anatomy can be seen liver, spleen, kidney and other internal organs swelling or bleeding. In the fry appear after the rotation can start to feed, feed 2 days later, can be poured "Yongle iodine" 2 mu/bottle, "Sanhuang powder" 2 mu/package processing; But remember not to kill insects, even if it is to check the wheel worm, ciliates, are not recommended to kill, such as fish fry completely ingested, and then deal with paRASites.
The above is a summary of the main disease regularity of California perch at seedling stage in Chengdu in recent years. I hope you can make a comprehensive analysis according to the actual situation of your pond to achieve the combination of prevention and treatment. Although California sea bass disease after the cure of the difficulty is relatively large, but clear the law of the disease can be less detours, not blind drug use, reduce the secondary injury resulting in death aggravation.
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