Print This Page

How Do You Get Rid of Jellyfish in Shrimp Ponds?

Daniel Gruenberg (daniel@acquestra.com): Does anyone have experience eradicating jellyfish from shrimp ponds with tea seed cake or saponins?

 

Robert Bauman (hankbauman@gmail.com): Daniel, in the 1980s, at the beginning of the growout cycle, tea seed cake was commonly used in the Philippines to kill fish in shrimp ponds.  Given that it didn’t harm the shrimp, I thought it was only toxic to vertebrates, so I’m not sure how it would affect jellies.

 

Durwood Dugger (ddugger@biocepts.com, http://www.biocepts.com/BCI/Home.html): Daniel, If I remember correctly both tea seed cake, Rotenone and other saponins only function with hemoglobin-based-blood systems, which is why they block oxygen transfer in fish, but not in the copper-based-blood system of shrimp.

 

Jellyfish don’t have a circulatory system (no blood), and oxygen is absorbed from the surrounding water.  As such, saponins are unlikely to have any effect on jellyfish.  Molecular oxygen transport in jellyfish seems to be poorly understood (chemically) and seems somewhat variable in species, like jellyfish, that are more or less algal symbiosis dependent.

 

Mark Napulan (kram_lewor501@yahoo.com): When we tested five ppm vinegar (pH 6) in a bucket with ten Penaeus monodon PLs and some jellyfish, the vinegar did not appear to affect the shrimp, but the jellyfish in the bucket weakened and melted away in three hours.  Although this is the easiest way of eliminating them, we still remove them by screening before stocking.  If you use vinegar to kill jellyfish during growout, proceed with caution because killing large numbers of them can lead to spikes in ammonia.

 

Daniel Gruenberg (daniel@acquestra.com): Saponins do not affect jellyfish.  Mark tried acetic acid, and it seemed to kill the jellyfish without affecting the shrimp.

 

He also changed the plankton structure which produced more diatoms, a good thing.

 

The saponins were my crazy idea, and I was wrong.  They don’t work on jellyfish.

 

Mark isn’t trying to kill fish.  He’s trying to kill jellyfish.

 

Daniel Gruenberg (daniel@acquestra.com): Nelson, while we are glad to see your random trivia about the general subject of jellyfish we were specifically looking for information from Listers who had experience managing jellyfish in a growout pond.

 

It’s a problem for Mark, and he is looking for people with experience in managing jellyfish in shrimp ponds—the topic of this discussion!  There are other venues and social media available for sharing random information not related to shrimp farming.

 

I mention this because if every time someone posted a question about shrimp farming, The List responds with Googled information not related to shrimp farming, the utility of this list is significantly reduced.  Please respect the subject of the discussion and the question of the original poster.  Let’s try not to go off on tangents.

 

Nelson Gerundo (nelsongerundo@yahoo.com): Daniel, you are insisting on trying to find a chemical treatment to kill jellyfish in shrimp ponds.  The most practical way is just to scoop them out.  Scooping this sluggishly, surface-swimming, brainless invertebrate is an inexpensive, practical way of getting rid of them.

 

I have had only a few encounters with jellyfish, and it’s my experience that it’s unlikely to find a jellyfish invasion in your shrimp ponds.

 

Daniel Gruenberg (daniel@acquestra.com): Nelson, I understand your point about scooping them out.  If you had read all my posts, you would have known that it is being done in earnest.  However, scooping doesn’t get the last one, and they continue to proliferate.  Also, your assumption that acetic acid’s mode of action is via pH is just wrong.  If you had read Mark’s post, you would have known that the amount of acetic acid used did not affect the shrimp, but the jellyfish slowly dissolved.  This cannot be due to simply pH change; otherwise, it would be better to just use a stronger acid.

 

Sources: 1. The Shrimp List (a mailing list for shrimp farmers).  Subject: Jelly Fish/Saponins.  April 13 to 18, 2017.  2. Bob Rosenberry, Shrimp News International, April 21, 2017.

Print This Page