A large number of vibrio bacteria were found in the body of the dead crab, and Li Ji frowned: "The pond vibrio of freshwater crabs should mainly occur in the high temperature season, and it is only mid-June now, isn't it?"

It is determined that it is a pond Vibrio infection, Ao Yuanzang is in a hurry, this bacterium is very powerful, the onset is violent, the mortality rate can reach 30% to 50%, and the bacterial flora is explosive, that is, there are already crabs infected and died, so it is estimated that there are already a large number of crabs infected with bacteria underwater.

Seeing that Li Ji judged the condition, his student raised the agar medium and asked, "Teacher, do you still want to do a microbiota culture test?"

Li Ji said cautiously: "Make one, provide two-way verification." ”

It is not uncommon for Vibrio to occur in summer crab farming, especially in recent years, due to government support and large market demand, the river crab aquaculture industry has developed rapidly.

In order to maximize efficiency, river crabs are stocked at high densities, and farmers use feeds with higher protein content in order for them to grow faster.

In this way, the crab will not float like a fish after death, or will hide at the bottom of the farm, resulting in the deterioration of the conditions of the breeding waters, coupled with the feeding of chilled fish and high-protein feed is easy to deteriorate, the river crabs will decline after eating, and once they are not eaten in time, they will quickly decay and pollute the aquaculture waters.

In this way, in the high temperature season, Vibrio will multiply and infect river crabs, resulting in the occurrence and epidemic of river crab vibriosis.

However, this is for breeding ponds, and there should be no river crab infection in a body as large as ambergris lake. The water quality in the lake is absolutely excellent, the breeding environment is also good, as the saying goes, "crabs first raise water", the water of ambergris lake is good, then there should not be a large-scale vibrio infection.

He told Li Ji what he thought, and Li Ji nodded and said, "You know a lot." ”

Ao Muyang smiled bitterly and said, "Let's make a living, after all, I am your closed disciple of Master Li." ”

Hearing this, Li Ji glared at him: "My closed disciple understands this? Shame on me, it is not only the temperature and humus high protein water quality that cause vibrio, you can take a look at the lake again, is there any problem?"

Ao Muyang looked at the lake, the sun was shining, the lake water was clear, dozens of small boats were slowly floating on the lake, and there were cheers from time to time.

He thought for a moment and said, "It's no problem. ”

Li Ji said patiently: "You open your eyes and look carefully. ”

Lao Ao opened his eyes to the maximum, and the corners of his eyes hurt, but he still didn't see anything.

Li Ji was helpless: "I asked you to open your eyes wide to let you observe more and use your brain to observe, you really widened your eyes, you, you, you...... Alas!"

Carelessly!

Lao Ao wanted to make progress, so he continued to look hard at the lake, in order to see far, he was still tiptoeing and stretching his neck, Ao Yuanzang followed him to see this, and a row of cormorants stood on the boat by the lake also posed in this pose, of course, they were not learning from the two, this is their nature to wait and see.

Li Ji pointed to the water in the lake and said, "Look down, what are you doing with your neck stretched? What are you doing in the lake? ”

Ao Muyang nodded and said, "Yes, there is Eloza." ”

In the early years, Land Rover gave him a batch of Elophylla, and after he raised it in the backyard breeding pond, he found that it was a great help for aquatic products, and Elophylla was the food of crabs, so when Ambergris Lake began to raise crabs, he planted a lot of algae in the lake, and it has been two years now, and it is growing very well.

Li Ji analyzed: "The water quality of Ambergris Lake is clear, which is not unrelated to the algae, but too much algae is not a good thing, especially now that the weather is hot, the algae will quickly rot and stink when they sink to the bottom of the pond after they die, resulting in a large oxygen debt in the bottom of the sediment." And you have to know that the lack of oxygen at the bottom of the lake is all day in June and July, and the shrimp and crabs crawling and swimming are very serious, which can easily lead to excessive ammonia nitrogen and nitrite in the mud at the bottom of the lake, and the proliferation of anaerobic bacteria and the breeding of vibrio flora. ”

This is true, Ao Muyang nodded, there are many algae, fish, shrimp and crabs in ambergris lake, and there are no people to fish on a large scale all year round, only the two activities of crab fishing in autumn and grass carp fishing in winter will indeed bring pressure to the ecosystem of the lake.

Li Ji said: "Not only that, the more tourists come to the lake, the more garbage the lake receives. Although you have arranged for people to constantly trawl and clean up the garbage, but the cleaning is all solid garbage, and the bacteria brought by the garbage itself have entered the lake and cannot be salvaged and destroyed, perhaps this is the source of infection. ”

Ao Muyang nodded heavily, and he asked, "Then how to eliminate Vibrio?"

Li Jidao: "From the analysis of the causes of Vibrio, it can be concluded that the biggest factor causing the outbreak of Vibrio is dissolved oxygen. The dissolved oxygen in the water body is too low, the sediment oxygen debt is large, and harmful substances such as ammonia nitrogen, nitrite, hydrogen sulfide and other harmful substances cause stress and weaken its ability to resist the invasion of external adverse factors. Under hypoxic conditions, aerobic microorganisms are inhibited, anaerobic microorganisms rise, and dominant species are easily formed, thus reaching or even far exceeding their pathogenic thresholds. ”

These words are very level, Ao Yuanzang cast a pleading gaze at Ao Muyang, Ao Muyang spread his hand and said, "Add oxygen to the bottom of the lake?"

Li Ji said: "This is a way to cure the root cause, and there is also a way to treat the symptoms, so I'll go back and ask my colleagues who specialize in crustacean zoology and aquatic pathology." ”

Ao Muyang immediately arched his hand and said: "Teacher Li, don't bother, I'll prepare a table of gluttonous feasts for you when you go back!"

Li Ji said with a smile: "Don't look back, it's better to hit the day than to choose a day, let's prepare tonight." ”

Ao Muyang: ┓( ́∀' )┏

When he came to dinner, Li Ji also brought a solution to the Vibrio outbreak.

The first is to identify the area of bacterial infection, according to the professional analysis of his colleagues, with the scale of ambergris lake, it is not the whole lake that has a vibrio infection crisis, but a problem at the bottom of a certain lake.

The reason why crabs die is because freshwater crabs are territorially aware during the shelling season, and they will not leave their territory easily, and they will not let other people of the same kind enter their territory.

After identifying this area, it is necessary to take the second step, to put oxygen concentrators and aerators into the waters, and organize people to clean up the bottom of the lake in the relevant waters, to take away the bait, dirt, and rotten weeds at the bottom of the lake.

At the same time, it is necessary to sprinkle medicine to the bottom of the lake to kill bacteria, and now there are effervescent tablets of vibrio inhibitors, which are scattered like bricks and thrown into the lake, just because there is no water flow fluctuation at the bottom of the lake, and the effervescent tablets can be safely applied to the problem waters.

Li Ji also told him that there are still many waters with vibrio infections, mainly because of this year's drought, except for a heavy rain in the spring, no rain has fallen so far, and there is no new water source in the pond in the lake, so there is no oxygen to bring in.

Lao Ao can't help this, he can't control the weather.

Hearing his answer, Li Ji sneered: "You are escaping, you haven't thought of a solution, you just said that you can't help it!"

Ao Muyang's heart moved after thinking about it, and said, "Then, let's have an activity for the Dragon King to pray for rain?"

Li Ji, who was drinking, almost choked: "Pray for rain? Why don't you have a brain? Can this be useful? You must be trying to find a way to make rain!"