Can wild crayfish be eaten, and how much is one jin?

On hot summer days, people gather at food stalls and late-night snack stands to drink and chat, and at such times crayfish is served. But most of the crayfish eaten now are farmed, so can the wild crayfish promoted by some vendors be eaten? How much does wild crayfish cost per jin on the market? The details are as follows.

A brief introduction to crayfish

Crayfish is a common freshwater crustacean in our country in recent years. Its scientific name is Procambarus clarkii, also called red swamp crayfish or freshwater crayfish. Like other crayfish, it has crab-like chelipeds, but its chelipeds have more prominent spines, and the spines on the carapace are also especially obvious, so it is more imposing than many crabs. Tracing its original home, it is actually from northern Mexico to the Florida region of the United States. Because its meat is delicious, it was sought after by many food lovers, and later it was widely introduced to other parts of the Americas, as well as Europe and Asia. Highly adaptable, it quickly took root around the world. It is a freshwater economic shrimp species and is widely welcomed for its delicious meat. Because it is omnivorous, grows quickly, and adapts strongly, it forms an absolute competitive advantage in local ecological environments. Its feeding range includes aquatic plants, algae, aquatic insects, animal carcasses, and so on. When food is scarce, it even cannibalizes its own kind. In recent years, crayfish has become an important economic aquaculture species in China. In commercial farming, escape must be strictly prevented, especially escape into pristine water bodies rarely visited by people. Its ecological competitive advantage over local species leads to destructive harm.

Crayfish like gentle streams and still-water habitats, marshes, ditches, mud flats, and ponds, especially environments rich in vegetation and fallen leaves. During the day they hide in burrows, at dusk they come out to forage, and at night they start all kinds of fun——this is also why crayfish fishing is done at night.

When the water temperature is 21-27°C, it is most suitable for their growth. Once the temperature is below 12°C, they hardly grow——this is also why crayfish-eating activities mostly take place in summer.

Can wild crayfish be eaten

“Crayfish live in polluted water bodies, eat garbage, are rich in heavy metals, and are extremely harmful to the human body. Eating too many will cause metal poisoning”……Are these all true? Crayfish can indeed adapt to various polluted environments, but this does not mean they like staying in very dirty places.

In fact, the reason crayfish can “tough it out” is thanks to their good detoxification and toxin-reduction mechanism. During metabolism, crayfish can gather and transfer heavy metals to the shell, and then move the toxins out of the body through continuous molting. This energy-consuming process means crayfish do not grow much meat and have difficulty storing energy to reproduce. In fact, they like clean water bodies and fresh food the most, as only then can they be large and reproduce abundantly. The crayfish on the market are basically large and thick-meated.

How much does wild crayfish cost per jin

In life, people always pay more attention to wild things, and the same is true for crayfish. Farmed ones are not as popular as wild ones, so the price is also higher. Below let us look at how much wild crayfish costs per jin, and the 2017 wild crayfish price. According to vendors, the purchase price of the larger “green heads” (green-shell crayfish, plump meat) was as high as 5 yuan each! You should know that at the peak crayfish production period, the purchase price of crayfish was only 5 yuan per jin. And according to the person in charge of the crayfish wholesale market in Jiyukou Town, Qianjiang City, manual farming currently has a purchase price of 25 yuan per jin for mixed shrimp, 15 to 20 yuan per jin for those below 5 qian, 25 yuan per jin for 5 to 6 qian, and 28 to 30 yuan per jin for those above 6 qian. They are mainly sold to Shanghai, Nanjing, and Suzhou. “In the week before this week, because crayfish had just entered the catching period, the amount of crayfish was relatively small, and purchase prices were all above 30 yuan, about 10 yuan higher than the same period last year.”

As for the crayfish market across the country, apart from Shanghai and Beijing remaining high, other regions are generally above 35 yuan! According to a veteran in the crayfish industry with more than ten years of experience, some time ago, the wholesale price of shrimp at Laohugou Market was very unstable. Before the season arrived, prices were 55-65! And some relatively well-known shrimp restaurants sell at about 188 yuan for 3 jin. “Because the season has not arrived, crayfish have not been listed in large quantities, so the price is too high and there is not much profit.”

Why crayfish is popular

1. Because most crayfish have very strong pollution resistance, they can still survive in water quality containing highly polluting toxins. When kept in aquariums, they can also effectively remove fish excrement and moss, making a very large contribution to water environment cleanup.

2. Crayfish have a very high protein content in their bodies, and their meat is soft and easy to digest, making it excellent food for people who are weak and need recuperation after illness; shrimp meat is also rich in magnesium, zinc, iodine, selenium, and so on. Magnesium has an important regulatory effect on heart activity and can protect the cardiovascular system. It can reduce cholesterol content in the blood, prevent arteriosclerosis, and at the same time dilate coronary arteries, which helps prevent high blood pressure and myocardial infarction. Crayfish contain astaxanthin, and astaxanthin is a very strong antioxidant. Scientists at Osaka University in Japan found that astaxanthin helps eliminate “jet lag” caused by time zone changes. In addition, crayfish can also be used as medicine, can resolve phlegm and relieve cough, and promote wound granulation and healing after surgery.

3. People in many countries around the world eat crayfish. Since 2009, global crayfish aquaculture production has been above 500,000 tons. The largest producer is the United States, followed by our great foodie nation——China. China's output exceeded 50,000 tons in 2003, increased to 80,000 tons by 2005, with an output value exceeding 303 million USD. Crayfish exported from China are mainly cooked foods, including shrimp tails, shrimp meat, shrimp paste, whole shrimp, spicy powdered shrimp, and so on, mainly sold to markets in Europe, North America, Japan and South Korea, and Southeast Asia.

4. Because their meat is firm, the roughly inch-long meat on the tail is, in the eyes of diners, incomparably delicious. Crayfish have a very high protein content in their bodies, accounting for about 16%-20% of total body weight, while fat content is less than 0.2%, and the meat is easy to digest. In addition, shrimp meat is rich in many important trace elements such as magnesium, zinc, iodine, and selenium. Crayfish shells are rich in astaxanthin. After deep processing, extracted chitosan, astaxanthin, and so on have relatively high economic value and are widely used in biological, pharmaceutical, food, chemical, and other industrial fields.

Attached: techniques for catching wild crayfish

1. Necessary preparatory work

1. Prepare nets and bait

In rural areas, many people use “a 1-meter-long multi-section grid” to catch crayfish. Each time you go to the wild to catch crayfish, placing 4-10 nets is enough. If you place too many at once, they are easy to lose.

The bait used is generally bait with a fishy and foul smell, such as crayfish bait sold in fishing tackle shops (or loach and eel bait), or beginning-to-rot pig offal (pig lungs, pig stomach, etc.); you can also use rotten potatoes, rotten sweet potatoes, and other root foods as bait. In the south, you can also use dried rapeseed cakes after oil pressing.

2. Choose catching locations

Wild crayfish are widely distributed in ponds, rivers and canals, and streams. Choosing rivers and ponds relatively close to where you live can save time and make it convenient to retrieve the nets.

2. Where can wild crayfish be caught in large quantities

1. Relatively shallow ponds

Because crayfish often live in shallow water areas, relatively shallow ponds have large numbers of wild crayfish. These ponds all have many aquatic plants, and the water quality is usually quite turbid. If the water quality in a pond is clear enough to see the bottom, there are very few wild crayfish in it.

2. Small ditches near residential areas

These nearby small ditches usually also contain large numbers of crayfish. Because urban residents sometimes dump a lot of household garbage and domestic wastewater into the river, the small ditches become relatively nutrient-rich, so wild crayfish can reproduce in large numbers.

3. Ditches around farmland

The water quality in farmland is all turbid, and because fertilizer is often applied, the fields are all rich in nutrients. Because ricefield eels and field mice dig holes in the field ridges, the nutrient-rich water in the farmland often flows into nearby canals, and wild crayfish very much like the environment here, so their numbers are very large.

3. Methods for catching crayfish

1. Place nets in the evening

It is recommended that you choose the evening (around 5 p.m.) to place nets in the target area (pond, river, or canal). If it is too early, on the one hand crayfish are not very active during the day, and on the other hand others may unintentionally (or even intentionally) take away your nets.

2. Choose shallow-water, grass-rich areas

When setting nets in the chosen ponds and ditches, you must choose areas with shallow water and relatively dense aquatic plants, because crayfish density is very high in these areas.

3. Notes on retrieving nets

(1) Retrieve nets as early as possible

When retrieving nets the next day, do not get up too late. It is recommended to go at dawn, for example around 5 o'clock. Otherwise, people who get up earlier may “take away” your crayfish nets and your “overnight harvest,” which is really not worth it.

(2) Prevent being pinched when retrieving crayfish

Wild crayfish all have thick large chelae, commonly known as “big pincers,” and they are as formidable as crabs. So when taking down caught crayfish, you must pay attention and avoid the “big pincers” to prevent being pinched. Just hold the crayfish by the antennae and lift it up.

4. 3 points to note

1. Pay attention to safety when placing nets

Especially in unfamiliar waters, there may be venomous snakes on pond banks, so pay attention to wearing tall boots (rain boots) when going. In addition, when setting nets, be careful not to use too much force, to prevent falling into the water yourself.

2. Mark them well

After placing the nets, remember to mark them well; otherwise, when retrieving the nets the next day, you will not be able to find the exact positions.

3. Pay attention to weather changes

Generally, summer and autumn are suitable for catching wild crayfish. In addition, when it rains heavily or thunders, it is not suitable to set nets.