Crab hunting in mangrove forests

(Baonghean) - From September (solar calendar) to March of the following year is the breeding season of sea crabs. During this time, crabs move into Lach Van estuary, then deep into the mangrove forest to live and reproduce... This is the time when people in Dien Van commune (Dien Chau) enter the "hunting" season for crabs to sell meat or young crabs to commercial crab farmers.

Seasonal"hunting" for crabs...

As soon as the sky was light, Nguyen Thanh and his wife (in Trung Phu hamlet, Dien Van commune, Dien Chau) rowed their boat to collect the "spoils of war" from the traps and traps placed at Lach Van estuary the night before. Although there were lucky and unlucky days, earning 300,000 - 400,000 VND/2 workers/day was easy; in rough sea months, when crabs raced into the mangrove forest, they could earn up to a million VND in a day... With skillful movements, Thanh slowly pulled the trap (also known as the octagonal stove) with a net with an iron frame about 6-7 meters long, catching 4 small crabs less than the size of a thumb. Mr. Thanh said: "Regardless of whether the crabs are big or small, the pond owner buys them all. Crabs the size of two thumbs or more cost 7,000-10,000 VND/crab, slightly smaller ones cost 2,000-4,000 VND/crab. On average, my wife and I catch about 50-60 small crabs a day. The fishing time is about 6 months, which is a decent income to cover our living expenses and send our children to school."

Having also participated in the profession of "hunting" sea crabs for many years, Mr. Nguyen Nhiem (Xuan Bac hamlet) said that this is the most suitable time to catch crabs. "Hunting" crabs looks like it is not simple at all. The place to catch crabs is in the areas with little mud, hard ground, sometimes the crab holes are deep in the roots of trees. With skillful operations, using both hands and digging with a hoe, then using a hook to "lure" the crab, it took more than 10 minutes for Mr. Nhiem to catch a crab weighing about 300 grams. It is called a hook, but in fact this is a small iron bar nearly 1 meter long, both ends are bent into a hook, when put into the hole, the crab will stretch its claws to clamp the hook, then the catcher will gently pull it out. "The crab caves are very deep, sometimes you can't reach them with your whole arm. At this point, the only way left is to use an iron hook to pull the crabs out. Honestly, after many years in this profession, it's not easy to distinguish whether there are crabs in the cave or not, because as soon as the water recedes, they come up to look for food and then disappear. Sometimes you can examine the cave for a whole day and there's not a single crab inside," Nhiem shared.

1 hectare of crab farming in Dien Van (Dien Chau) brings in a profit of nearly 300 million VND.

For a long time, the people of Trung Phu and Trung Hau hamlets have maintained a profession that, although not rich, has helped them stabilize their lives, which is the exploitation of shrimp, fish, crabs... at the mouth of the creek and in the mangrove forest. The profession of "hunting" sea crabs has been in the making since 1995. By 2000, when people implemented the model of raising shrimp and crabs together, the demand for crab seeds increased sharply, so at its peak, the whole commune had nearly 40 households participating in the crab catching profession. According to Mr. Hoang Do (in Trung Hau hamlet) - a person with more than 15 years of experience in the profession: "In addition to using octagonal nets, placing traps and blocking the flow of Lach Van, to catch crabs in the mangrove forest, especially meat crabs, people must have experience to be highly effective. When the mangrove tree is planted in soft soil, the roots grow strongly, creating nooks and crannies, which are places where sea crabs like to live. And when the tide is low, the sea crabs will leave thin footprints like lines outside the cave entrance.

Professional crab catchers only need to look at the footprints on the outside to know if there are crabs in the cave. When discovering new footprints, the catcher uses a hook-shaped iron hook to slowly enter the cave. Because the bottom of the cave often has water, the hand holding the hook must be very sensitive to know the condition of the crab cave. If you find a crab, turn the hook, choose the direction so that the whole crab is completely in the curve of the hook, then gently pull it to the cave entrance, use your hand to press the hook firmly into the ground so that the crab does not run away, at the same time use the thumb and middle finger of the left hand from behind to squeeze the last part of the crab's legs so that the crab cannot be pinched. And you have to be very skillful, otherwise the crab will break its claw and its price will drop from grade 1 to grade 3, losing hundreds of thousands of dong."

“The young sea crabs follow the tide into the mangrove forest and make burrows under the tree roots. After a while, the crabs will crawl out of the burrows and follow the water flow to the mouth of the creek. At that time, we can easily catch them with a bagua net. Previously, we only caught meat crabs. Now that crab farming has developed, pond owners always have a high demand for young crabs, so their income has increased significantly. Natural sea crabs are dark green in color, with bright red patches under their claws. Farmed sea crabs are lighter in color and lack shine and luster..." - Mr. Hoang Do added.

There are many ways to catch baby crabs and meat crabs, but the most popular is still using a bagua net, a net with a bottom, and a bottom; only "professionals" use iron hooks. This bagua net is only produced in China, and consists of many compartments and chambers, and the animal can go in and then cannot get out. In Trung Hau hamlet, many families bought this "bagua oven" and the more they looked at it, the more they admired the "talent" of the Chinese. In the past, people also went crab fishing. Sea crabs are very greedy but also very clever. If the fisherman jerks the fishing rod too quickly and is impatient, it will be difficult to catch them. When the crabs have eaten the bait, the fisherman must wait 5-10 minutes for them to be "drunk" on the bait and lose their guard before pulling them up gently. The bait is simple, just a giant tiger prawn or a small trash fish.... But now they have switched to "hunting" crabs at night. With the advantage of being near the estuary, crab farming is developing, generating high profits, and low investment capital, so many people in Dien Van have switched from shrimp farming to crab farming, making the job of "hunting" for seeds even more advantageous. The mangrove forest is increasingly green, not only protecting the village but also being a place where fish, shrimp, and crabs come to breed and generate income for the people here.

Open farming directionsustainable crab

Dien Van has an estuary leading to the sea, this is an advantage that can provide abundant seawater for the entire 65-hectare brackish and salty aquaculture area of ​​the commune. In recent times, facing increasingly complex changes in climate, weather, polluted farming environment, and unstable quality of shrimp seeds, production costs are always increasing, causing many shrimp farming households to suffer losses and no longer have the ability to reinvest in production. This is the reason for Dien Van aquaculture farmers to find a new direction, a new farming object to replace part of the ineffective shrimp farming area. Sea crabs are a familiar species to aquaculture farmers and are one of the objects with economic value. At the same time, the farming technique requirements are not complicated, the natural seed source is abundant, the investment level is suitable, etc., which are favorable conditions for this farming object to develop further.

As one of the pioneers in converting from raising tiger prawns to raising crabs, Mr. Phan Niem (Van Nam hamlet) excitedly said: "Previously, my family raised tiger prawns on a nearly 1ha earthen pond. But due to several epidemics and unfavorable weather, seeing that raising shrimp was increasingly difficult, in 2002 I boldly converted all the shrimp area to raising crabs. Right from the first crop, although I raised and learned from experience at the same time, I made a profit, and the next two consecutive crops were both big winners, earning more than 50 million VND/crop. The advantage of raising crabs is that they are harvested year-round, so farmers always have cash. Now, not only me but many people in the commune are more "addicted" to crabs than shrimps, because crabs are easy to raise and "sure to eat". The food source is always abundant, including trash fish and sardines caught from the sea, so there is no need to worry about output, especially during the tourist season or holidays when there is not enough imported goods for traders".

According to Mr. Phan Niem, to achieve economic efficiency, farmers must pay attention to the selection and release of breeds, because success or failure depends largely on this stage. Crabs should be released around March - April (solar calendar), because at this time there are many natural breeds, and the water environment is favorable. Healthy breeds must be selected, of uniform size, and bright color; depending on the size of the crabs, determine the appropriate release density (the best size of the crabs to be released must be ≥2cm/crab, release 1 crab/m2). Before releasing the breed, the water level in the pond must be controlled from 1.2 - 1.3 meters, the pH from 7 - 8.5 and the salinity from 20-25 parts per thousand. In the first month of release, there is no need to change the water, in the second month, change according to the amplitude of the tide, and from the third month onwards, change the water about once every 10 days to ensure the water environment is always clean, in order to create conditions for the crabs to move and molt well. "Although crab farming is less risky than shrimp farming, the loss rate is always high, about 40% or more. During the farming process, crabs are often infected with fungi and viruses. When they encounter fungal diseases, their gills will turn black, and when they encounter viral diseases, their legs and claws will fall off... There is currently no medicine to prevent or treat these diseases, but if these two diseases appear in a pond, they will not spread quickly and will not cause mass deaths like other diseases in shrimp, so they will not leave farmers empty-handed," added Mr. Phan Niem.

Mr. Tran Minh Tuan - Head of the Agriculture Department of Dien Van commune said: Before 2000, people here were familiar with the method of releasing crabs mixed with shrimps, extensive farming combined with the form of harvesting and compensating. Although the efficiency was not high, crabs have "saved" shrimp farmers. Investing in intensive crab farming is a new method and has strongly developed in the past 6 years. With the goal of finding suitable aquatic species to increase economic efficiency per unit area. Quickly applying scientific and technical advances to expand the farming of aquatic species, in 2012, the Agricultural Extension - Fisheries Extension Station of Dien Chau district implemented the construction of a commercial crab farming model at Mr. Tran Loc's household - Xuan Bac hamlet, with a water surface area of ​​0.5 ha, releasing 5,000 crabs, the average size of the crabs released was 40/kg. After more than 3 months of farming, the survival rate reached 60%, for a total commercial crab output of 750 kg; With a selling price of 320,000 VND/kg at the pond, after deducting expenses, Mr. Loc earned about 170 million VND. Thus, by applying technical measures on care processes and using biological products in the crab farming model, the productivity and profit are much higher than traditional crab farming. The model has the potential to be replicated on a large scale.

Currently, the whole Dien Van commune has 67 households raising crabs, mainly concentrated in Trung Hau and Trung Phu hamlets with an area of ​​over 20 hectares; the annual output value reaches about 1.5 tons/ha, generating a revenue of nearly 10 billion VND. Sea crabs are one of the objects with economic value and are favored by the market because they have high nutritional content. In addition, commercial sea crab farming is the basis for farmers to transform the structure of raised breeds, as well as the method of raising, contributing to increasing income, improving family economy, creating jobs, developing diverse breeds, creating new products to serve the increasing market demand.

Article and photos: Ngoc Anh