How to farm mantis shrimp? Mastering these aquaculture techniques is key

Autumn weather is cool, and nighttime activity is in full swing, making it the perfect season for late-night snacks. For a foodie like me, it basically means late-night snacks going down every single night. Counting up these late-night snack varieties, the one I always have to order is shrimp. There are so many varieties of shrimp, and the cooking methods are even more diverse. Sometimes I wonder, with so many people eating shrimp every day, often ordering them by the jin after jin, can such a huge supply actually meet market demand? Later, a professional shrimp farmer explained it all in detail, so let me take everyone to have a look.

Mantis shrimp aquaculture techniques

Mantis shrimp, also known as squilla, can be farmed in several ways. I believe that regulating water during the farming cycle is the key. The quality of the water determines the success or failure of raising mantis shrimp in a pond. The decisive factors of water lie in the following 4 specific physicochemical indicators, and this is the general solution to mantis shrimp farming techniques.

1. Water pH

This value is very critical, as it affects other physicochemical indicators in the aquaculture water. Divided by the early, middle, and late stages of the farming cycle, in the early stage the pH of the aquaculture water is generally within the normal range of 8.0 to 8.5, and at this stage pH does not need to be adjusted. But by the middle and late stages of farming, pH keeps soaring, and in some ponds the daily maximum even reaches above 10, earning it the name soda water. At this stage, pH must be paid attention to. If the daily pH fluctuation is greater than 0.5 and remains above 9 for a long time, you must be especially careful. If this continues for several days, it is an early sign that the pond is developing problems. For adjusting water pH in general, for ponds that are too low, I use quicklime. For bottom substrates that are originally acidic soil (mangrove areas), dolomite powder should be used as a base. For ponds with excessively high pH, organic acids + lactic acid bacteria (EM bacteria) and other live bacterial preparations are used to adjust it gradually. The general principle is to change pH by adhering to the principle of gradual decrease (or increase), with a daily change of 0.2 being appropriate.

2. Total alkalinity

This value is the core data determining stability in the water. Simply put, total alkalinity is the total amount of substances in the water that can neutralize acid (hydrogen ions); in other words, it is the sum of the three carbon-containing ions in the water. Survey data over 5 years show that successful ponds have total alkalinity values between 80 and 120 (German degrees) throughout the entire farming cycle, and the value remains relatively stable. Overall, I believe that total alkalinity is a more comprehensive measure of overall water indicators than water pH. If its value is less than 70, the daily pH change in the water is relatively large. Here, for adjusting total alkalinity, I believe dolomite powder has the best effect and is also cheap. Its only shortcoming is that the dosage is relatively large.

3. Total hardness

This value determines the health condition of mantis shrimp. In water, it is mainly characterized as the sum of cations such as calcium and magnesium. In natural water bodies without human disruption, this value generally remains within the normal range, but in aquaculture water bodies it changes more noticeably. If total hardness remains too low for a long time, mantis shrimp are prone to soft-shell disease, and pathogens such as bacteria and viruses can easily invade; if total hardness remains too high for a long time, mantis shrimp have difficulty molting. Generally, for mantis shrimp farming, maintaining 80 to 120 (German degrees) is relatively moderate. My guiding theory for adjusting total hardness is to first adjust total alkalinity. Only when total alkalinity is in the moderate range should total hardness be considered for adjustment. In general, when total hardness is too low, calcium dichloride is added for adjustment; when total hardness is too high, baking soda is used for adjustment.

4. Salinity

This value determines the growth rate of mantis shrimp. As is well known, desalinated farming of mantis shrimp results in relatively fast growth. Proper desalination farming of mantis shrimp to increase growth rate is beneficial. More importantly, under appropriate salinity, the disease resistance of mantis shrimp is enhanced. Adjusting salinity is easily solved by changing water, but the general principle of water exchange is that the daily water exchange volume should be less than one third of the total pond water volume.

Selection and transportation methods for mantis shrimp

For mantis shrimp, you can choose artificially farmed females or female mantis shrimp that have already mated in natural sea areas.

Although they can reproduce once body length exceeds 8 cm, in order to ensure quality and increase the number of eggs carried, it is better to choose those with body length above 2 cm and body weight above 30 g. In addition, when purchasing parent mantis shrimp, note that the time out of water should be short, gonadal development should be relatively good, the body should be robust, appendages complete, without injuries, strong in vitality, bright in body color, and sensitive in response to external stimuli. After purchase, parent mantis shrimp should be transported to the hatchery as quickly as possible and placed in ponds for temporary holding and cultivation. Transportation methods include live-fish boat transport, nylon bag oxygenated transport, dry moisture-retaining transport, and canvas bucket transport with water.

Parent mantis shrimp are first bathed in 200×10-6 formalin for 3 minutes, then those with complete appendages and lively behavior are selected and placed into previously disinfected cement ponds (9 m×4 m×1.2 m), filtered fresh seawater is added, and aeration is provided to restore their vitality and hold them temporarily. During the first 1 to 3 days in the temporary holding pond, the water temperature should preferably be 1 to 2 degrees C higher than that of the sea area. If the water temperature rises too quickly or too high, parent mantis shrimp are prone to premature birth or miscarriage. After that, raise the temperature at a rate of 0.5 to 1.0 degrees C per day to 21 to 22 degrees C and hold them temporarily for 20 to 30 days, feeding a small amount of fresh sandworms, small shrimp, clam meat, and so on, so that the gonads can further fatten. Although during the reproductive season female squilla basically stop feeding and their stomachs are almost empty, when the temperature is 22 degrees C and the gonadal coefficient reaches more than 14%, the eggs in the produced egg mass are clear and basically form a mass, which means mature eggs.

Control methods for fungal diseases in mantis shrimp

Fungal disease in mantis shrimp is caused by mold spores invading larvae or eggs. Infected fertilized eggs become opaque and stop developing, and infected larvae move sluggishly, experience muscle necrosis, sink to the bottom, and die.

Tools and water used for shrimp should be strictly disinfected, dead eggs and dead larvae should be removed promptly, and the water quality should be kept clean. When disease occurs, trifluralin can be applied to the hatchery water at 0.01 g per cubic meter and splashed over the entire pond.

Overwintering aquaculture techniques for mantis shrimp

1. Build a good overwintering shed. Do not rush to cover all the plastic film of the overwintering shed. Wait until the water temperature clearly drops below 20 degrees C (Macrobrachium rosenbergii mantis shrimp) and 16 degrees C before covering it completely. The overwintering shed should be built on the principle of practicality and low cost. Apart from the plastic film, which needs to be replaced every year, other materials can be used continuously for 2 to 3 years.

2. Maintain good water quality. Because water cannot be changed frequently in winter, maintaining good water quality is key. The main technical measures are: continuous aeration for 24 hours, by laying plastic pipes with many small holes at the bottom of the pond and connecting them to a blower outside the shed. This aeration method has low cost and good effect; apply beneficial bacteria once every half month to degrade ammonia nitrogen in the water and reduce the formation of harmful substances such as nitrite; in winter, when water temperature is low, mantis shrimp eat little, and excessive residual bait can easily accelerate water deterioration, so the feeding amount should be controlled; when the outside temperature rises, open the shed entrance promptly for ventilation, and when the water temperature is suitable, appropriately replace with new water.

3. Harvest in time. The longer the overwintering aquaculture period, the greater the chance of aquaculture accidents, so harvest and bring to market when the price is suitable, especially during the Spring Festival.

Mantis shrimp meat is tender and nutritious, especially rich in protein, and is very suitable for many pregnant women to eat during pregnancy. From the selection of mantis shrimp to farming to fungal control, is everyone clear now? There is still only a short time until winter, and farming them now to sell in winter is a great opportunity. Do not miss it.