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Ignatius (email@example.com): Dear hatchery owners and managers, how many pounds of Artemia (brine shrimp cysts, eggs) are you using to produce one million postlarvae (PLs)? How much does a one-pound can of medium-quality Artemia cysts cost?
Billy Setio (firstname.lastname@example.org): Hi Ignatius, I use more cysts to produce one million PLs than most other hatcheries, up to 16 cans per million PL-12s. Depending on the PL stage sold, some hatcheries use as few as six cans per million PLs. Generally, the more you use; the better your survivals will be during growout. In my opinion, it’s important for PLs to get all the nutrients they need for early growth, and nothing does that better than live Artemia.
In Indonesia, a one-pound can of Artemia cysts varies from $50 to $60, and I think it will get more expensive in the future.
Billy Setio (email@example.com): Ignatius, one more thing to consider is the quality of the Artemia that you use. You have to consider the percentage of the cysts that will hatch. If you use medium-quality cysts, which may have a hatch rate of 80%, they may be 3-5% cheaper than cysts with a hatch rate higher than 90%, but you’re better off with the 90% hatch rate.
Dallas Weaver (firstname.lastname@example.org): Is anyone using enriched live rotifers to replace all or most of the Artemia in PL production? With fish, using yeast-based feeds with enriched live rotifers, I found that I could produce rotifers for much less than Artemia. The larval fish species I was rearing on these feeds could go all the to dry feed with no Artemia.
The bottom-line cost was about 1/3 the cost of Artemia, which is not always available, so if you have a rotifer production systems, you can avoid the availability issues. I was challenged to prove that my rotifer-production system could produce large quantities of Artemia at the Hubbs-SeaWorld Research Institute in San Diego, California. A test was run and the results were presented at a World Aquaculture Society meeting [Shrimp News:It takes a few seconds for this PowerPoint file to download to your desktop, but it’s worth the wait because it contains all the information you might need to build your own rotifer culture system.]. The test ended with the onset of winter and poor temperature controls, but up to that point, we produced rotifers much cheaper than the cost of producing live Artemia. Hubbs-SeaWorld had no use for large quantities of live rotifers in the winter, so the experiment was ended. At my facilities, I operated year around without any rotifer crashes or interruptions. I only needed about a billion rotifers a day.
I fed excess rotifers (about a kg/day) to some shrimp, and all sizes would eat them.
My 10-cubic-meter system produced 3 to 5 kg of live rotifers a day. A larger system would be more economical.
Roger Kelso (email@example.com): I use a similar concept in my shrimp nursery, and it works very well. In addition to feeding a yeast-based feed to the rotifers, I also have an algae-based system to feed the rotifers that in turn feed the shrimp.
Jorge Cordova (firstname.lastname@example.org): Dallas, great contribution! Your system would work well in Ecuador, where there is a non-stop need for live enriched feed for shrimp larvae. In Ecuador, five to six pounds of Artemia are used to produce a million PLs. A few enriched Artemia products are also available.
Ignatius (email@example.com): Does anybody have any data comparing the amount of Artemia fed per million PLs and pond survivals and growth rates?
Alain Michel (firstname.lastname@example.org): I think shrimp hatcheries use lower-quality Artemia than fish hatcheries because shrimp get their unsaturated fatty acids from unicellular algae and because Artemia costs less than microparticulate feeds. It’s also easier to maintain the water quality with Artemia than with microparticulate feeds.
I would be very surprised to see data that showed that postlarvae that get a lot of Artemia performed better than postlarvae cultured with a good microparticulate feed. There are plenty of microparticulate feeds on the market, but they make it more difficult to control water quality. Biofloc is a good answer.
Carlos Conroy (email@example.com): My system is also based on rotifers, and we add fatty acids to provide even better nutrition. This works better than anything else that we’ve tried. Yeast also provides a lot of nutrition, but not enough to replace Artemia. That problem can be resolved by adding some fatty acids.
Nelson Gerundo (firstname.lastname@example.org): With Penaeus vannamei, I have experienced better survival and turnover from mysis to early PL when Nannochloropis-fed rotifers are used before transitioning to pure INVE’s Artemia nauplii and INVE’s microencapsulated diets.
With P. monodon, survival and turnover from mysis to early PLs with INVE’s microencapsulated diet—before transitioning to INVE’s Artemia mix for nauplii and INVE’s microencapsulated diet—are good enough.
For P. monodon broodstock, nauplii production works better when Artemia biomass is used along with polychaetes, squid, frozen clams, some minced beef liver, and INVE’s broodstock maturation diet.
Dallas Weaver (email@example.com): Nelson, in theory, it is possible to build a highly-automated, near-zero-discharge, rotifer-production system with costs in the less than $10/kg live-weight production range. If we could eliminate most Artemia consumption by using rotifers in shrimp, the natural variations and market speculations in Artemia cyst cost and availability would become less relevant and make shrimp aquaculture less dependent upon a wild product with finite production.
It would require some R&D to make the design truly idiot proof and crash proof, so the question becomes how big would the market be for rotifer-culture systems that produced 5+ kg a day?
If hatcheries had extra rotifer production, what would happen if large numbers of rotifers were added to a new pond along with PLs? Much like Daniel Gruenberg’s diatom/copepod system, you could create a green algae/rotifer ecosystem that may impact Vibrio! I have no idea how well V. parahaemolyticus would do in an algae/rotifer system, but rotifers will ingest and digest most bacteria. Has anyone tried adding rotifers to a new pond to see if you could create an algae/rotifer dominated ecology? Without shrimp, such an ecology would allow large algae (too big for rotifers) to become dominant.
Nelson Gerundo (firstname.lastname@example.org): Dallas, the only reason I think rotifers are good in P. vannamei larviculture is to increase the survival from mysis-2 to PL-2, where the major mortality tends to occur (in our experience). Beyond PL-3, rotifers tend to be ignored in favor of Artemia nauplii and microencapsulated feeds, including flakes. Artemia nauplii, on the other hand, are too big for myses and frozen dead nauplii tend to burst and slime the tanks.
Perhaps rotifers are too small for PLs as they molt and get larger.
Besides, rotifers tend to starve and crash and become pollutants after being ignored by older PLs in the larviculture tanks, which are devoid of microalgae at this time. We use Chaetoceros calcitrans for the nauplii, zoea and mysis stages, but gradually stop using them after the larvae metamorphose into PLs.
With regards to the larviculture of P. monodon, higher than 90% survival from mysis to early PLs is attained without the use of rotifers, and the mysis and the PLs are just as happy and strong with just Artemia nauplii and microencapsulated diets. I have not used any other brand other than INVE, and that is why I mentioned it in my previous post. The problem with P. monodon is they get very aggressive when they transform from being planktonic to benthic, starting about at PL-6. From P-7 to PL-16, the number of larvae starts to decline because they begin to eat each other.
Durwood Dugger (email@example.com, http://www.biocepts.com/BCI/Home.html): These are interesting and useful discussions on the finer points of the nutrition and feeding of larvae and PLs, but I think it is time to examine the priority of where we focus our cost reduction efforts.
If you look at the average cost of seedstock to the farmer that buys them from a commercial hatchery in the USA (as shown in Samocha/Hanson 2014 work), it is under 5% of the overall cost of producing market-size shrimp. In their studies the cost of feed is about 48%, labor is about 23.5%, and energy is about 5%. All the other costs are well under 5%. If you are more vertically integrated and producing your own PLs from your own hatchery, your seedstock costs might be well under 2% of your overall production costs, depending on the economies-of-scale. The point here is the basic cost/benefit ratios that you are struggling to reduce need to be prioritized.
Saving a few dollars on the cost of larval feeds is great if your savings are clear-cut and significant. Rotifers would have been adopted by the global shrimp hatchery industry as a primary larval food and brine shrimp usage reduced if rotifers were more economical. Yes, the absence of this adoption of rotifers could be a tradition bias favoring brine shrimp, but we must also assume that significant economic motivations (significant savings from rotifer usage) would eventually over-ride tradition bias or other inertia type biases and or marketing biases created by formulated larval feed purveyors), and we might conclude from this that any cost savings are comparatively small in the best case.
Good business logic suggests that your efforts would be considerably more productive in lowering your overall shrimp production costs if you attack the larger production cost components, where potential savings are larger per unit effort and might have a higher probability of providing higher savings. For example, if your feed costs are 50% of your production costs and your seedstock costs are 5% and assuming you applied the same effort to achieve a 1% savings on your major production cost components—your potential to lower your overall production costs (all other things being equal) has a potential ten times greater potential by applying the savings effort to reducing your feed costs (be it in feed conversion ratio, price negotiation, formulation or ingredient sourcing) than reducing your seedstock costs to achieve the same 1% for those savings.
I’m not saying that reducing seedstock costs is not important and shouldn’t be done, but from a time and cost/benefit ratio standpoint, it makes good economic/management sense to prioritize your operating cost reduction efforts by the categories where your efforts stand the greatest probability of producing overall product cost reduction results.
So, if you have lowered your feed costs to the absolute lowest possible, your labor costs to their lowest, your energy costs to their lowest—all without reducing your yields—then yes, you should focus on your seedstock costs.
It certainly looks like rotifer culture is a worthwhile alternative to be included in the feed mix. I think one of the reasons it’s not common in the industry (or as common) is that it requires producing another live organism, with the corresponding planning, investment, equipment and management, while using Artemia from a can is very convenient. It’s similar to the situation where many hatcheries don't produce their own algae anymore and just buy it from another hatchery, sometimes with unexpected consequences.
Dallas, would a non-automated rotifer production system—where you would not have to worry about complicated recirculation and where you had manpower at reasonable costs—provide a consistent product?
Durwood Dugger (firstname.lastname@example.org, http://www.biocepts.com/BCI/Home.html): Ignatius, I agree; a stand alone larval culture business, where Artemia is the primary feed, has a different cost structure.
The effort you spend in developing the necessary protocols and systems for rotifers (remember it’s a species that doesn’t naturally have either the necessary critical nutrients or energy budgets that are provided by brine shrimp nauplii) is at a high risk of not providing significant cost savings.
Unless as Dallas says you can develop a full proof system with significant and demonstrated and quantified advantages, it may end up as a wash when competing with Artemia. Normally speaking adding another critically dependent culture species to the primary production system species’ management/culture chain has not worked out well. In any case, I wish you well and great success in all your endeavors.
Billy Setio (email@example.com): Ignatius, shrimp farming is very complex. I have been in the hatchery business for so long that I’ve discovered that the farmer’s primary goals are survival rates and growth rates. I observe my biggest customers who are buying PLs from several hatcheries to see which farms are getting the best growth and survival rates. Then I look at the hatcheries that supply those farms to see how they are feeding their postlarvae.
Dallas Weaver (firstname.lastname@example.org): Durwood, you are right again. It probably isn’t cost effective to develop a super rotifer system at this time. Spending the same R&D money on improving feed conversion ratios would have a bigger payoff.
Daniel Gruenberg (email@example.com): Billy, I buy the cheaper (lower hatching rate) Artemia, decapsulate them, hatch them with 20 parts per million of Sentrox from CPAC Asia to cut the Vibrios, and then wash and use both hatched and unhatched Artemia in the larval tanks. This saves a lot of money, and all the feeds are natural and have near-zero, green Vibrio counts, with just a hundred (per milliliter) or fewer of the yellows.
Nelson Gerundo (firstname.lastname@example.org): Dallas, rotifers are undoubtedly very important in most marine fish larviculture. In P. vannamei larviculture, however, they are less important, and only at certain larval stages.
Source: The Shrimp List (a mailing list for shrimp farmers). Subjects: (1) Brine Shrimp, (2) Digest Number 4431, and (3) Artemia and Pond Performance. January 4 to 6, 2017. 2. Bob Rosenberry, Shrimp News International, January 9, 2017.
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