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Video—Shrimp Grazing on Copepods

Daniel Gruenberg’s Natural Pond Management


Mark Napulan ( In response to some comments from Nelson Gerundo ( on The Shrimp List, Mark Napulan, writes:


Here is a one-minute video of a 5-gram, 40-day-old shrimp grazing on copepods.  As you can see in the video, it is picking and sucking up copepods like crazy.  Based on evidence from feeding trays, when there are plenty of copepods around, shrimp don’t consume much artificial feed.  The densities of copepods usually decline after the first sixty days of growout.  [Shrimp News: Here’s a link to a  great video on copepods.]


Nelson Gerundo ( Mark, “sucking up copepods like crazy”?  What I see is a shrimp teased by the agile and alert copepods around it while confined in a small 100 ml Pyrex glass beaker desperately trying to catch and put any high speed swimming copepods into its mouth at random with its paired maxillipeds, while its clawed periopods lay steady on the bottom of the beaker to support its body and head.


Robert “Hank” Bauman ( Looking at the video multiple times, I can't say that I saw the shrimp actually consuming a copepod.


Mark Napulan ( In Pakistan, I used Daniel Gruenberg’s Natural Pond Management (NPM) technology and had average feed conversion ratios (FCRs) of 1.08 in 10 ponds.  We were able to maintain diatom and copepod populations up to 60-70 days of culture.  We had one pond that got whitespot with a FCR of 1.02 and survival rates of 76%!  Based on those experiences and previous experiences in the Philippines, I’ve found that viral infections only manifest themselves when water quality parameters are not controlled or when major macronutrients are out of balance.


I am replicating this work in my demonstration ponds in Bangladesh and India, and a friend in Palau is using my fertilizer premix.  I have done trials in Vietnam to validate the nutrient ratios for diatom enhancement.  So far, results are good in those countries.  I’m learning to adjust every time at different site conditions.  Nothing compares to real hands-on experiences.


Nelson Gerundo ( Mark, do you have photomicrographs of the intestinal contents of the shrimp being raised in a shrimp pond with copepods at 30 days of culture, 40-DOC, 50-DOC, 60-DOC and 70-DOC?


Your video of a 5-gram, 40-day-old shrimp grazing on copepods is just one moment in time.  This does not mean that shrimp will feed on copepods their entire adult lives.


Daniel Gruenberg ( Nelson, Mark is just sharing his experience with you.  Durwood Dugger and many others have all posted similar stories that when given the option, shrimp prefer to eat live feed or dead copepods to pelleted feed.


Bob Rosenberry ( Back in 2013, on The Shrimp List, Gruenberg described his Natural Pond System (NPM) like this:


I have fought a long battle trying to convince shrimp hatcheries and shrimp farmers of the benefits of copepods.  Although copepod blooms are difficult to manage in open ponds, they are part of our complete concept of “natural pond management” or NPM.  Despite some major successes at large farms, I find it difficult to convince farmers of the significant benefits of copepods in shrimp farming.


Recently, we began to make some new strides in this regard, and now we have set up a demonstration farm to specifically model our NPM concept of aeration and feed control.  These ponds are lined, but the concept works in earthen ponds.


Our technology was originally developed for certified organic production, but now we are trying to promote it more broadly as simply a better and more economical way to produce shrimp sustainably.


We would like to help more farmers learn the natural way to grow shrimp without lime, dipthrex, copper sulphate, chlorine, antibiotics and a host of other toxic chemicals that are put in ponds, so that shrimp farmers can achieve consistent, high-quality harvests with reduced feed conversion ratios, better quality and lower costs of production.


Here’s a little tidbit: On the farm where I’m doing my demonstration, the owner and managers knew the benefits of copepods, but followed C.P. Foods’ strategy of killing everything in the pond first, which resulted in plankton blooms that varied qualitatively and quantitatively, even in adjacent ponds during the same crop.  I assured the demonstration farm that I could create copepods for them, but they were skeptical.  Then the farmer’s brother, who operates a tilapia operation, developed problems with blue-green algae while working with a different water source with a salinity around four parts per thousand.  I fertilized one of his low-salinity tilapia ponds, and after four days, it looked like an Artemia tank, but instead of Artemia, it was full of copepod nauplii.  Microscopic examination of the water revealed massive amounts of diatoms (Chaetoceros sp.).  Oh, and the blue-green algae also disappeared!


It convinced the shrimp farmer to follow our natural pond management (NPM) concept.  I am quite confident that I can create copepods for you in any pond!


Daniel Gruenberg ( People who have used my Natural Pond Management (NPM) know it works.  Most of the problem is that the vast majority of shrimp ponds can’t maintain such a huge biomass of copepods after 30-40 days of culture.  NPM can maintain the high levels even up to 180 days!


So we will continue to share our experiences with farmers in hopes of offering a better, more effective way of managing not only whitespot, but most all diseases through minimizing stress and promoting the natural health of the animals.


Mark, thanks for sharing your experience.


Nelson, despite our differences, I really admire your skills as a photographer.  Perhaps we can arrange for you to visit an NPM farm someday and take photos of the intestinal contents of the shrimp at various stages!


Nelson Gerundo ( Daniel, I meant no harm to Mark.  Besides he is a Filipino, like me.  I care.  Also, this is not about photography.  This is about being convincing me that the shrimp in your diatom/copepod dominate shrimp pond have been consistently predominantly eating a copepod composed diet through the growout period, from the day the postlarvae were stocked all the way to harvest—everyday—and corroborating it with photomicrographs of the intestinal contents of shrimp at 30-DOC, 40-DOC, 50-DOC, 60-DOC and 70-DOC.


Daniel Gruenberg ( That's why I'd like to invite you to come look for yourself and take photos for everyone to see.


Mark focused on producing shrimp, not on taking photos.


I have mentioned it before, and I would really like to see some of your photographic skills capture what is going on in our ponds.


Again NPM is not the only way to grow shrimp or control disease, but it sure seems to be working where we try it.  Where specific pathogen free (SPF) seedstock is not available, we think it’s a good alternative.


Sources: 1. The Shrimp List (a mailing list for shrimp farmers).  Subject: Shrimp Grazing on Copepods.  July 30 to August 1, 2017.  2. Bob Rosenberry, Shrimp News International, August 1, 2017.


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