1. What is the growth environment of crayfish?

What kind of environment is most suitable for the growth of crayfish?

In the Yuanjiang section of West Dongting Lake, we found shrimp farmer Lao Gan.

Lao Gan told us that every summer, crayfish will be active in the shallows.

In winter or when crayfish shed their shells and reproduce, crayfish will lurk in caves to protect themselves.

From June to August every year, crayfish are at their most plump, and this is also the best time for people to catch and enjoy them.

With green grass and shallow beaches, this water area is where Lao Gan and the others often fish for lobsters.

Shrimp farmers say that crayfish like to live in clean places, and in places like smelly ditches, crayfish do not grow very big.

Investigation shows that the rumor that crayfish grow better in dirtier places is unfounded.

2. Are most of the crayfish currently on the market artificially farmed?

Crayfish are omnivores and mainly eat animals, including small fish, shrimps, plankton, benthic organisms, and algae.

According to shrimp farmers, crayfish have a strong reproductive capacity and will ovulate two to three times a year.

It usually only takes 2 months from the hatching of shrimp eggs to the maturity of crayfish.

The shrimp farmer said that he can catch up to three to four hundred kilograms per person at most, and there are probably thousands of shrimp farmers like him in the waters of Dongting Lake.

Every day, about 30 tons of crayfish are shipped from Yuanjiang Market to all parts of the country.

Waters with shallow water plants are favorites of crayfish, because this is not only a place for them to live, but also a hidden place for them to shed their shells.

In addition, crayfish also like to drill holes, and their destructive capabilities are also very powerful.

They often penetrate field ridges and destroy dikes.

Combining these characteristics of crayfish, local shrimp farmers have specially made a shrimp fishing tool - the Earth Dragon King. The shrimp farmers set a mesh hole in each section of the Earth Dragon King, which is simple and convenient but can invite shrimps into the urn.

Shrimp farmers say there is no need for artificial breeding because crayfish have a strong reproductive capacity.

The survey shows that wild crayfish are enough to meet market demand, and the cost is much lower than artificially cultured crayfish.

There is no economic benefit to artificially raising crayfish.

Therefore, there is no basis for saying that the environment for artificially raising crayfish is harsh.

3. Are there many crayfish caught from the ditch?

June, July and August every year are the best seasons for fishing crayfish in Dongting Lake. In late August, as the temperature of the lake water drops, crayfish begin to dig caves at the bottom or shore of the lake to wait for the coming summer.

At this time, the shrimp fishing work on the lake has gradually declined, but there are more and more people fishing for shrimp in the river ditch.

The tools for catching shrimp in river ditches are very simple. Shrimp farmers usually only need a shovel for digging and a pair of gloves for catching shrimp.

The shrimp farmer said that the water in the cave is very clean and the environment is the same as the growth environment of eels and loaches.

The holes dug by crayfish are usually between 1.5 and 2 meters. In addition, the weather gets cooler after autumn, so it is quite laborious to dig out crayfish in the river ditch. It only weighs six or seven kilograms a day.

The survey shows that due to the cooler weather, the time suitable for fishing in river ditches is very short.

And there is not much economic benefit.

Therefore, most of the crayfish currently on the market are crayfish caught in the lake area.

4. How to distinguish crayfish dug from river ditches from crayfish caught on the lake?

When we asked about the difference between lake shrimp and ditch shrimp, shrimp farmer Lao Gan made a comparison between lake shrimp and ditch shrimp.

The crayfish raised in clean water are larger, the shrimps in the lake are lighter and redder, and the shrimps in the ditch are darker.

Tip: Since crayfish grow in different environments, it is recommended to eat crayfish produced in the lake area.

The characteristics of crayfish produced in the lake area are: bright colors, large individuals, and relatively consistent head and trunk size ratios.

At present, the crayfish sold on the market in my country are mainly produced in Dongting Lake, Poyang Lake, Honghu Lake, Hongze Lake and other lake areas.

Taking Dongting Lake as an example, the daily output in the peak season is about 30 tons, and in four months it is about 3,600 tons.

Together with several other lake areas, the total output of these major producing areas in the peak season is about 17,000 tons.

This is basically the same as the current national annual consumption of crayfish of 20,000 tons.

Due to the high protein content in crayfish, the content of zinc, iodine, selenium and other trace elements in shrimp meat is also higher than that of other foods.

It also tastes good, so crayfish has become very popular in many cities in recent years.

Some places have even set off a "red storm" of summer dining.

But our reporter also has some worries, because the situation in some waters where crayfish are produced is not optimistic.

During the investigation of the waters of Dongting Lake, we found that there was a stone tablet erected in the floating aquatic products trading market in Yuanjiang City, "There are schistosomiasis here, and protection is required when entering the water."

So if crayfish survive in such waters, is it possible to become a host for schistosomiasis?

To this end, we visited the Yuanjiang Municipal Health and Epidemic Prevention Bureau.

The director told us that schistosomiasis only lives in oncomelania, and there is no evidence that schistosomiasis exists in crayfish.

But experts also confirmed that crayfish are indeed the intermediate host of paragonimiasis.

5. Is it possible that crayfish carry parasites and heavy metals?

We sent crayfish brought from Dongting Lake waters and crayfish purchased from the Beijing market to the Institute of Tropical Diseases of Beijing Friendship Hospital for testing.

The investigation showed that there is currently no evidence that crayfish carry schistosomiasis, paragonimiasis or are contaminated with heavy metals.

In addition, both Schistosoma and Paragonimus are afraid of high temperatures.

Therefore, crayfish can be eaten with confidence as long as they are cooked at high temperature.