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How To Induce Molting

 

Andrey Vungtau (andrey.vungtau@yandex.ru): Listers, I can’t find a reliable source on how to induce simultaneous molting in a shrimp pond.  Some of the suggestions I’ve heard are adding EDTA (ethylenediaminetetraacetic acid), BKC (benzalkonium chloride), saponin to the pond, or quickly lowering the water level in the pond.  Has anyone had a successful experience with any of these methods?  Please suggest alternative methods.

 

Patrick Wood (patrickjwood@yahoo.com): When you say “reliable source”, do you mean controlled scientific research?

 

You might try stressing the shrimp with a chemical or physical stressor to induce molting—but there could be risks with the technique you select.  Here are some other factors you should consider:

 

• Lunar cycles play a role in molting.

• To induced molting in the entire pond, it helps to have a relatively

   homogeneous population.

• Under the right conditions, growth spurts occur after molting.

• Shrimp have softer shells after molting.

 

Andrey Vungtau (andrey.vungtau@yandex.ru): Patrick, by “reliable source”, I mean a reliable, confirmed practice that has worked for others.

 

John Birkett (jbirkett42@yahoo.com): Andrey, here are a couple of techniques for inducing molting.

 

• Add fresh water to drop the salinity.

• Do a big water exchange, and add some calcium hydroxide or Copper

   Control (below). This was our favorite technique, and it couldn’t be beaten.

 

Nasser Ayaril (nasserakv@naqua.com.sa): John, what’s Copper Control?

 

Nelson Gerundo (nelsongerundo@yahoo.com): Nasser, Copper Control is a trademarked product supplied by Argent Chemical Laboratories in Washington State, USA.  It is an algaecide whose main active ingredient is copper mixed with triethanolamine.  It’s very toxic to aquatic animals including fish, snails, copepods and daphnia.

 

Nasser Ayaril (nasserakv@naqua.com.sa): Nelson, thank you.

 

Viswanathan Deenadayalan (viswa.bio@gmail.com): Hi all, here’s an easy formula for inducing molting in a one-hectare pond:

 

• 6 liters of molasses

• 100 grams of yeast

• 5 kilograms of sugar

• 100 liters of pure water

 

This preparation should be made before 6:00 a.m. and kept in an airtight barrel and applied (with aerators on) before 5:00 p.m.  To increase the intensity of the molting, prepare the mixture again by 6:00 p.m. and apply by 5:00 a.m. the next morning.  The molts should begin appearing by 11:00 a.m.

 

Dallas Weaver (deweaver@me.com): Viswanathan, how, why does your formula work?

 

Bob Rosenberry (bob@shrimpnews.com): I emailed Viswanathan and asked him if he knew why the procedure he described works.  Here’s his answer:

 

Viswanathan Deenadayalan (viswa.bio@gmail.com): I don’t know the science behind it, but I’ve seen it with my own eyes, and it works.

 

Sources: 1. The Shrimp List (a mailing list for shrimp farmers).  Subject: How to induce molting in shrimp.  September 23 to October 20, 2017.  2. Bob Rosenberry, Shrimp News International, October 22, 2017.

 

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