Vaname Shrimp Molting Time Is Affected by Moon Phases? Is it true?

Hello Mister / Ms Shooters! Have you ever heard that vaname shrimp molting time is affected by the moon phase? In your opinion, is this statement a myth or a fact?

That statement is true. Moonlight can trigger several physiological functions in the shrimp's body and increase the production of thyroid compounds that trigger the molting process. However, apart from moonlight, there are several other factors that trigger molting in vannamei shrimp. For more details, check out this article!

What is Molting?

Molting is the process of changing the shell or shrimp shell which usually occurs during the process of increasing the volume of the shrimp's body. Molting occurs because when the shrimp body volume increases, the shrimp shell, which is stiff, does not expand too. To adjust to this, the shrimp shells which contain chitin, calcium salts, protein, and fat peel off by themselves.

Later, the shrimp shells that have peeled off will be replaced with another layer of shell or skin underneath. The process of molting occurs with increasing age in shrimp. The process of molting in shrimp is not long, only 3-8 weeks. After the molting process is complete, a new shrimp shell will form and harden within hours.

That is the meaning of molting and how the process takes place in shrimp. So, will there be any problems with the shrimp during molting?

Problems that Often Arise When Molting Shrimp

Just like the cultivation process, when molting takes place there will be problems that often interfere with the growth of vannamei shrimp. One of the problems is the threat of cannibalism or other shrimp predation.

As a result of the shell peeling off during molting, the shrimp will secrete a liquid containing amino acids, enzymes and organic compounds. The aroma of this liquid will actually provoke the appetite of other shrimp so that cannibalism appears. To avoid cannibalism in shrimp, you can carry out a feeding strategy by measuring the level of shrimp feed requirements based on careful observations. That way, the shrimp will feel enough of the feed given and their cannibalism instinct will decrease.

When molting occurs, vannamei shrimp tend to have no appetite. In contrast to the treatment carried out when shrimp are susceptible to cannibalism, shrimp that experience this phenomenon should reduce their daily feed intake. Feed reduction aims to reduce the occurrence overfeeding which can lead to the deposition of feed on the bottom of the pond. Despite their insufficient feed intake, shrimp use the protein already present in their bodies to form a new shell after the molting process is complete.

Shrimp that are molting are also very sensitive to changes in pond water, especially the volume and brightness of pond water. To avoid this, you can reduce the frequency and volume of changing pond water. However, if the brightness level of your shrimp pond water is not stable, you should immediately apply fertilization to stabilize the brightness of the water. 

Factors Affecting Shrimp Molting

There are several factors that influence the emergence of molting in vannamei shrimp. One of the factors is the phase of the moon. The moon phase, especially the new moon phase, is the highest phase for molting in shrimp in ponds. The light emitted from the moon can trigger several physiological and biochemical functions in the shrimp's body. Moonlight can increase the production of thyroid compounds in the form of ecdysterone in shrimp hemolymph. These compounds can stimulate molting and exoskeleton in shrimp. Usually this exoskeleton decomposition process influences or stimulates other shrimp to molt, thus allowing mass molting to occur.

The occurrence of a lunar eclipse will also increase the activity of the spheroid organ lymphoid cells in vannamei shrimp. These cells are used by shrimp as an immune system to fight viruses and diseases. This happens because molting shrimp are more susceptible to disease because the shell that functions as their outermost defense has not been fully formed.

Apart from the new moon phase, the half moon phase and the full moon phase also affect vannamei shrimp molting. The half moon is one of the peaks of shrimp molting due to high levels of ecdysteroids or hormones that control molting in Arthropods and Crustaceae at that time. This is in accordance with the conditions in the pond. Shrimp usually start molting 1 week before the full moon or during the half moon phase. Meanwhile, the full moon also affects molting because the electromagnetic radiation or gravitational pull generated is high enough to trigger the release of neurohormone in shrimp.

Apart from the moon phases, other factors that can affect molting in shrimp are internal factors such as shrimp hormones. Hormonal factors can cause vannamei shrimp to molt during the spawning or egg laying period. 

Apart from hormones, internal factors can also be stress on shrimp. Vaname shrimp that are exposed to severe stress also experience molting as a way to defend themselves. 

How to Overcome Molting Based on Moon Phases

The care you take for vannamei shrimp during the molting process will determine the success of shrimp farming, because shrimp that fail to molt will die. How to deal with molting shrimp when the moon is full or based on the phase of the moon can be done by reducing the amount of feeding according to the phase. Moderate feeding during the molting phase is carried out to maintain water quality and prevent shrimp from disease. Reduced feeding is done 3 days before and 3 days after the dark moon/new moon and the bright moon/full moon.

To expedite the process of pre-molting, during molting, and post-molting, you can stabilize the pond salinity value with regular water circulation so that the shrimp are not stressed. Add minerals and lime for mineralization so that the shrimp's mineral needs are met and molting can run perfectly. Then, ensure that the levels of calcium, minerals and phosphorus in the pond that the vannamei shrimp need to form new shells are maintained.

A product that has been proven to help form shrimp shells during the molting process is Mineral Fix from Elanco. Mineral Fix is a macro mineral supplement that functions to increase alkalinity and helps shell formation during the molting process. Mineral Fix can also help maintain the pH of pond water and precipitate suspended solids. Its use is also very easy, you can apply Mineral Fix directly to pond water.

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