For shrimp farmers, understanding the molting phenomenon in shrimp is one of the keys in ensuring optimal growth for their cultivated shrimp.
Molting or the shedding of shrimp shell is a phase that impacts the overall health and survival of shrimp.
This article will discuss about the molting phase in shrimp, the stages, and how to handle shrimp in each of those stages. We hope you can optimize shrimp growth during this crucial process.
What is Molting?
Molting is a process when shrimp experiences shedding and growth of new shell or exoskeleton. Molting occurs several times throughout shrimp's life cycle every 3-8 weeks.
Although molting is a natural part of shrimp life cycle, farmers need to understand this process well. This is because shrimp are more susceptible to diseases during the molting process due to the loss of protection from the shedded shell.
Thus, farmers must pay special attention to shrimp when they are molting. This can be done by providing a stable environment while regularly monitoring water quality and providing necessary nutrition to reduce stress in shrimp.
Stages of Molting in Shrimp
There are four stages of molting in shrimp, which are pre-molting, molting, post-molting, and inter-molting. Here is a detailed explanation for each of the stages:
1. Pre-Molting
Pre-molting is the preparation phase before shrimp begins molting. In this phase, shrimp prepares itself to shed the old shell and replace it with the new one.
During pre-molting, shrimp produces certain enzymes and hormones required to soften and shed the old shell.
Some shrimp starts to show different behavior during pre-molting, such as lack of appetite and more passiveness. Shrimp will look for a protected area to reduce their overall activity.
2. Molting
Molting is a phase where shrimp removes its old shell from its body.
Shrimp does this by puffing out their body to push the shell out.
This process usually takes several hours and is considered a risky phase as shrimp has no protection during this phase.
After successfully removing the old shell, shrimp will grow a new, softer shell. This new shell requires more time to harden and strengthen itself to provide ample protection for shrimp.
3. Post-Molting
Post-molting is a phase that occurs after shrimp changes its shell. During this phase, shrimp will focus on physical recovery and adapting with the new shell.
The process of forming new shell requires a large amount of energy. Shrimp will increase its metabolism to support the growth and hardening of new shell, requiring more energy during this stage.
The new shell will gradually harden until it can provide enough protection for shrimp. After the shell has finished hardening, shrimp will be more active in finding food and carrying out its regular activities.
4. Inter-Molting
Inter-molting is a phase between molting periods when shrimp already has hard shell and is able to carry out activities regularly.
During this phase, shrimp will find food, move, and interact with other shrimp within their environment. They will spend more time to grow as they no longer focus on growing new shell.
Next, shrimp will enter the pre-molting phase again as a preparation for the upcoming molting stage. They will produce enzymes and hormones and undergo physical changes to prepare for the next cycle.
How to Handle Shrimp During the Molting Stage
Berikut di antaranya: Now that you are familiar with the molting stages of shrimp, it's time to learn what farmers should do to handle and care for shrimp during molting.
1. Pay Attention to Pond Water Quality
- Control Water Quality – Make sure to always maintain pond water quality. This includes stability of calcium concentration which helps shrimp form new shell.
- Monitor Minerals – Regularly check the concentration of phosphorus and other minerals needed for shrimp when forming new shell.
- Supply Minerals – Improve water quality stability by supplying minerals needed by shrimp regularly as a resource for shrimp during molting.
2. Manage Shrimp Feed Amount
Adjust shrimp feeding with their molting phase. When shrimp have finished molting, they tend to have higher appetite to boost growth, thus requiring more feed.
However, during the pre-molting stage, they require less feed, thus it is important to reduce feed. This helps prevent uneaten feed and maintain water quality.
3. Monitor Farm Environmental Conditions
- Monitor Molting Stage – Monitor and record the shrimp molting stages in the pond to understand the molting patterns and cycles, which can assist in future planning.
- Ensure Environmental Stability – Ensure that the pond's environmental conditions remain stable during the molting process to reduce stress in shrimp.
Mass Molting Phenomenon in Shrimp and How to Overcome It
During the full moon phase, shrimp farmers often worry about mass molting occurring in their cultivated shrimp. There is, in fact, a biological mechanism that can explain the connection between the full moon and mass molting in shrimp.
Moonlight triggers certain physiological and biochemical functions within the shrimp's body. One of these functions involves the increased production of thyroid compounds, specifically ecdysterone, in the shrimp's hemolymph. This compound plays a significant role in regulating the molting or shedding of the shrimp's exoskeleton.
Based on research by Rusaini & Owens (2019), molting occurs variably during the full moon phase in tiger shrimp, with the highest recorded molting during the new moon phase at 36.96%.
When molting occurs, shrimp tend to fast and utilize the protein in their bodies to form a new exoskeleton within a few hours.
This process is very risky, as shrimp become more vulnerable to changes in water quality, especially to maintain their body's osmotic pressure. If left unchecked, this can lead to osmotic shock, where excessive water is absorbed into the shrimp's body cells.
The exoskeleton decomposition process during molting triggers other shrimp as well. Fluid containing amino acids, enzymes, and other organic compounds increase the appetite of shrimp which are not currently at the molting or post-molting stage, increasing the risk of cannibalism.
Here are some tips to anticipate mass molting:
- Regularly check for shrimp's molting stage – Checking and recording molting stages can be done during sampling, allowing farmers to predict the molting cycle in the pond.
- Maintain water quality – Water quality must be maintained, especially salinity, to prevent drastic changes that could lead to shock in shrimp
- Reduce feed depending on the molting stage – Controlling feeding during the molting phase is done to prevent overfeeding, which can negatively impact water quality and trigger disease outbreaks.
- Add more minerals – Giving mineral treatments such as calcium and phosphorus is important for shrimp to speed up the formation of new shells.
Conclusion
Molting is a crucial phase that affects the growth and health of cultivated shrimp. To ensure the success of the molting process, farmers need to understand various aspects of this process.
This includes the needs of shrimp during the pre-molting, molting, post-molting, and inter-molting stages, as well as maintaining the pond environment throughout these phases.
In summary, here are the steps that farmers must pay attention to while shrimp go through the molting phase:
- Pay attention to pond water quality
- Manage shrimp feed amount
- Monitor shrimp molting phase carefully
- Monitor farm environmental conditions
With proper handling during the molting stages, you can minimize failure risks due to molting and ensure that your shrimp can grow healthy and well.
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Resources:
- Aquaneo. 2020. Improving the Molting Periods in Farmed Shrimp in order to Promote Growth.
- ISW. 2019. Mengenal Molting pada Budidaya Udang.
- Rusaini, & Owens, L. 2010. Effect of moulting and lunar rhythms on the lymphoid organ spheroid (LOS) cells of the black tiger prawn (Penaeus monodon). Journal of Experimental Marine Biology and Ecology. 389: 6-12.
- Rusaini, & Owens, L. 2019. The effect of viral infection on the relationship between the LOS cells and moulting stages of the black tiger prawn (Penaeus monodon). AACL Bioflux. 12(4): 1087-1101.
- Suryati, E., Tenriulo, A., & Tonnek, S. 2013. Pengaruh pemberian ekstrak pakis sebagai moulting stimulan pada induk udang windu (Penaeus monodon. Fab) di hatchery. J. Ris. Akuakultur. 8(2): 221-229.
