Adult apocyclops in a larval tank?

[LordJoshaeus]

Cool! I came up with a design for constantly harvesting parvocalanus (and perhaps Apocyclops)...here is a crude sketch;

In brief; the adult Parvocalanus are kept in the taller, light blue container in the back, which is kept aerated by 1/4th of an aquarium airline. Every 2 hours, the water pump is turned on and floods the culture with water from the larger container the culture it situated in, causing water to flow through a tube (with a 100 micron filter bag attached to the culture end to avoid capturing mature copepods) into a second collection container (the shorter one that is dark blue here). The collection container also has 1/4th of an air line (the remaining 1/2 of an airline keeps the large container circulated), but its only drainage is blocked by 25 micron screen, capturing nauplii and small copepodites removed from the main culture; these would be harvested and either fed to larvae or used to start another culture. Due to the short lifespan of these pods, each culture would be set up for only two weeks; the culture would be started with 3 nauplii per liter on day 1, allowed to grow out until day 7, and then harvested daily until day 14 (at which point it is restarted with new seawater and pods); once a week at least some of the large container's water is changed. Live microalgae (likely Isochrysis if Parvocalanus is cultured in this setup) would be provided in sufficient quantities to tint the water.

Advantages;
- Should allow much higher egg/nauplii production than otherwise possible for such a small culture
- Water changes can be done without harming the pods

Disadvantages;
- Microalgae needs to be fed to the whole culture rather than simply the culture, due to its recirculating nature

What do you think of this idea?

EDIT: I almost forgot! I am using a near-identical blue tub (I think mine is from walmart, though...they are $5 there last I checked) for a container pond this year.

 

[LordJoshaeus]

I came up with a very clever idea...maybe I could use cracked cell Chlorella powder to feed Apocyclops? The reason Apocyclops cannot use live Chlorella is because they cannot digest through their cell walls, but since humans also have that problem the cells intended for the powder are 'cracked' to allow the nutrients to be available for digestion.

 

[ThRoewer]

I came up with a very clever idea...maybe I could use cracked cell Chlorella powder to feed Apocyclops? The reason Apocyclops cannot use live Chlorella is because they cannot digest through their cell walls, but since humans also have that problem the cells intended for the powder are 'cracked' to allow the nutrients to be available for digestion.

Definitely worth a try - you got a source for it?

 

[LordJoshaeus]

Definitely worth a try - you got a source for it?

Ebay. This, for example; https://www.ebay.com/itm/Chlorella-...hash=item1ce7dd43f4:m:m8G5dqezaHb7Qm5YG2rD4Vw

8 ounces (or 227.79 grams) doesn't sound like a lot...but microalgae cultures rarely have more than 1 gram of algae per liter of culture, so this is effectively 60 gallons of chlorella culture in dry form. I am also looking into seaweed/kelp powders. I've even tossed around using 5-50 micron golden pearls as a feed component, though not as the sole diet (Apocyclops prefer eating food particles 6-21 microns in size, but have been observed readily predating juvenile rotifers, so they can eat larger items...I was thinking of putting the golden pearls through one of my 25 micron filter bags to remove the larger particles). Wild apocyclops rarely eat cyanobacteria from what I read, so spirulina powder is not likely to be used as a component in my future cultures.

 

[ThRoewer]

Cool! I came up with a design for constantly harvesting parvocalanus (and perhaps Apocyclops)...here is a crude sketch;

In brief; the adult Parvocalanus are kept in the taller, light blue container in the back, which is kept aerated by 1/4th of an aquarium airline. Every 2 hours, the water pump is turned on and floods the culture with water from the larger container the culture it situated in, causing water to flow through a tube (with a 100 micron filter bag attached to the culture end to avoid capturing mature copepods) into a second collection container (the shorter one that is dark blue here). The collection container also has 1/4th of an air line (the remaining 1/2 of an airline keeps the large container circulated), but its only drainage is blocked by 25 micron screen, capturing nauplii and small copepodites removed from the main culture; these would be harvested and either fed to larvae or used to start another culture. Due to the short lifespan of these pods, each culture would be set up for only two weeks; the culture would be started with 3 nauplii per liter on day 1, allowed to grow out until day 7, and then harvested daily until day 14 (at which point it is restarted with new seawater and pods); once a week at least some of the large container's water is changed. Live microalgae (likely Isochrysis if Parvocalanus is cultured in this setup) would be provided in sufficient quantities to tint the water.

Advantages;
- Should allow much higher egg/nauplii production than otherwise possible for such a small culture
- Water changes can be done without harming the pods

Disadvantages;
- Microalgae needs to be fed to the whole culture rather than simply the culture, due to its recirculating nature

What do you think of this idea?

EDIT: I almost forgot! I am using a near-identical blue tub (I think mine is from walmart, though...they are $5 there last I checked) for a container pond this year.

I was thinking about a collection box like this which would just be placed/floated into the culture container:

It could run continuously or intermittently.
The meshes would be on exchangeable frames so that they can be easily cleaned and exchanged for different sizes as needed.
As pump I would use this: PonicsPumps Submersible Pump 40 GPH

It's just a crude sketch. I got to draw it up in SolidWorks when I have time.

 

[Skydvr]

In tank culturing may be helpful for supplemental feeding and assistance with detritus control, assuming you can find a proper copepod species that will not predate the larvae. I thought about this a little and decided it would probably be easier and more reliable to just use a wide low flow vacuum and siphon into the sump once or twice a day. I prefer natural methods where I can use them, but realized this will probably be far easier to maintain.

I don't have my notes on me and I forget what the nauplii size is for Apocyclops is, but I would consider going bigger than 25 micron if you can. 45 might be better. I've got limited amounts of mesh on hand right now and ended up making a filter to transfer and scale up my tigriopus with 25 micron mesh and it turned out to be quite a pain. The water was fairly clean and I had difficulty getting it to flow through the screen. I was only filtering a 500mL flask, so I made a fairly short filter from a Sustainable Aquatics bottle. I couldn't really get enough head pressure to get it to drain continuously without overflowing. I had to constantly run my finger across the outside of the mesh to get the water to drain. The bag may work better though, just a thought.

I've been trying to work out how to make things a little more hands off as I am working towards being able to start breeding while still working full time with an hour commute (assuming normal work schedules resume). I've been considering daily harvesting and enriching in a small container that is on a continuous drip into the larval tanks. I have read of some increased success with green water in the larval tanks, but I am not sure that running algae densities high enough to maintain proper copepod/rotifer enrichment will provide the best environment for the larvae. Those articles with daily harvesting look promising. I was assuming that I would need to have multiple cultures with a rotating harvesting schedule. I was going to experiment with daily harvesting to see what I could get for nauplii, but figured it wouldn't work out in my favor and I would have to supplement with rotifers. Harvesting daily will also ensure that you are acquiring the smallest nauplii possible.

Daily harvesting with a rotating batch culture seems like the way to go. Pull off a small portion of the daily harvest and place into a recently cleaned vessel to scale up the replacement culture. This will let you do a complete harvest daily, always pulling the smallest nauplii, and allow you to always have cultures with young adults that have the highest fecundity. You will also never be too far away from having a new culture that is just about ready to start producing should one of the running cultures crash (assuming it isn't feed or environmental).


Where did you get the numbers for nauplii to feed rate?
The only stuff I remember for feed rates on Reed's site was for rotifers, which can be a lot more prolific and voracious than copepods. I think I was looking at closer to 2mL of RGcomplete for a 3gal bucket (~10L usable vol) with a 20% harvest rate for 300k/day. There are other products in the RG series with much higher densities than RGcomplete if you don't mind adding the pH buffers and ClorAmX yourself. Rotifer Diet would be 0.6mL/day for the same harvest quantity. I need to find out the recommendations on RGcomplete, but the higher density products can be frozen.
I found some metered airless pump bottles that dispense 1mL/pump. Breaking up the larger portions into more manageable sizes and freezing may be the way to go. The space savings, reduction in work, and reduction in energy costs may be worth it. Especially if like me, you don't have the ability to work with cultures outdoors and don't have a lot of available space to dedicate to cultures (though I am working on developing a more energy efficient method for dense culturing of phyto and diatoms). Of course, this won't work if you need a motile algae or diatom, unless you go through enough to justify the concentrated products before they start losing too much of their nutritional value or start dieing off.

Reed's has a really good PDF on their Apocyclops culturing methods. They also mention the airlift harvester the the University of Florida developed.

I think that the version of those buckets that Tractor Supply carries is a bit more heavy duty and not that much more expensive.

If you are looking to get a larger starter culture, Reed's will work with you for that. Tie the order in with your LFS's order and you should be able to save on the shipping. Sustainable Aquatics and a few others should be able to work with you as well. Most would be willing to sell larger quantities in a bag. If you know when you are going to need them in advance, you can always scale up from a retail bottle. Add volume as the culture grows, which is pretty quick once things get going.

 

[Larry L]

That's an interesting design, the only potential downside I see is the pump maybe running dry when the screens clog up (especially since it is behind the fine mesh, probably 40 microns).

Most collecter designs I've seen use airlifts to pull water from behind the more course mesh screen (around 75 microns) and then let the water gravity feed out through the fine mesh, so worse case if the fine mesh clogs the water just overflows and returns into the culture container. E.g. https://edis.ifas.ufl.edu/fa188 or

 

[ThRoewer]

That's an interesting design, the only potential downside I see is the pump maybe running dry when the screens clog up (especially since it is behind the fine mesh, probably 40 microns).

Most collecter designs I've seen use airlifts to pull water from behind the more course mesh screen (around 75 microns) and then let the water gravity feed out through the fine mesh, so worse case if the fine mesh clogs the water just overflows and returns into the culture container. E.g. https://edis.ifas.ufl.edu/fa188 or

The pump could easily be replaced with an airlift if there are issues. Though one of the issues I have is to find a reliable air pump. For running a larger number of cultures you would pretty much best served with a regular piston compressor - but that's not really something you can do at home where people want to sleep at night...

The problem I see with the Vossen trap is cleaning the mesh.

I actually like the UF design. It just needs to be scaled to fit smaller culture vessels.

BTW, where is the best place to buy the mesh?

 

[Skydvr]

1qt paint mixing containers and 3/8" or 1/2" PVC/CPVC is what I am considering, though that may still be a bit too large for a 3 gallon bucket. There is a brand of gelato and sorbetto that has nicely sized clear plastic containers that are fairly rigid and about the right size for a smaller culture vessel. Though it may not be tall enough if you want to use very small mesh sizes.

I've ordered mesh from Florida Aqua Farms, but there selection is somewhat limited for the smaller mesh sizes. I need to find some other sources myself.

If you are going to sanitize somewhat frequently with bleach, avoid nylon mesh. It will break down with repeated soakings.

 

[Skydvr]

Look into linear air pumps. They will move more air than a standard diaphragm pump and tend to be quieter. Jehmco have a good reputation and are rebuildable. People run them 10-15 years before rebuilding.

Super Luft Pump used to be good, but they got bought by a larger manufacturer and went downhill. If you can find one of the older ones and replace the seals, it will run for another 20+ years.

 

[ThRoewer]

1qt paint mixing containers and 3/8" or 1/2" PVC/CPVC is what I am considering, though that may still be a bit too large for a 3 gallon bucket. There is a brand of gelato and sorbetto that has nicely sized clear plastic containers that are fairly rigid and about the right size for a smaller culture vessel. Though it may not be tall enough if you want to use very small mesh sizes.

I've ordered mesh from Florida Aqua Farms, but there selection is somewhat limited for the smaller mesh sizes. I need to find some other sources myself.

If you are going to sanitize somewhat frequently with bleach, avoid nylon mesh. It will break down with repeated soakings.

McMaster-Carr has FDA grade chemical resistant polypropylene mesh, but the smallest size listed is 100 µm. Often they can get also things that are not listed on their website so it is worth asking if they can get smaller sizes. Downside is that they are not cheap.
If you go with stainless steel (316) then they go down to 30 µm

 

[LordJoshaeus]

In tank culturing may be helpful for supplemental feeding and assistance with detritus control, assuming you can find a proper copepod species that will not predate the larvae. I thought about this a little and decided it would probably be easier and more reliable to just use a wide low flow vacuum and siphon into the sump once or twice a day. I prefer natural methods where I can use them, but realized this will probably be far easier to maintain.

I don't have my notes on me and I forget what the nauplii size is for Apocyclops is, but I would consider going bigger than 25 micron if you can. 45 might be better. I've got limited amounts of mesh on hand right now and ended up making a filter to transfer and scale up my tigriopus with 25 micron mesh and it turned out to be quite a pain. The water was fairly clean and I had difficulty getting it to flow through the screen. I was only filtering a 500mL flask, so I made a fairly short filter from a Sustainable Aquatics bottle. I couldn't really get enough head pressure to get it to drain continuously without overflowing. I had to constantly run my finger across the outside of the mesh to get the water to drain. The bag may work better though, just a thought.

I've been trying to work out how to make things a little more hands off as I am working towards being able to start breeding while still working full time with an hour commute (assuming normal work schedules resume). I've been considering daily harvesting and enriching in a small container that is on a continuous drip into the larval tanks. I have read of some increased success with green water in the larval tanks, but I am not sure that running algae densities high enough to maintain proper copepod/rotifer enrichment will provide the best environment for the larvae. Those articles with daily harvesting look promising. I was assuming that I would need to have multiple cultures with a rotating harvesting schedule. I was going to experiment with daily harvesting to see what I could get for nauplii, but figured it wouldn't work out in my favor and I would have to supplement with rotifers. Harvesting daily will also ensure that you are acquiring the smallest nauplii possible.

Daily harvesting with a rotating batch culture seems like the way to go. Pull off a small portion of the daily harvest and place into a recently cleaned vessel to scale up the replacement culture. This will let you do a complete harvest daily, always pulling the smallest nauplii, and allow you to always have cultures with young adults that have the highest fecundity. You will also never be too far away from having a new culture that is just about ready to start producing should one of the running cultures crash (assuming it isn't feed or environmental).


Where did you get the numbers for nauplii to feed rate?
The only stuff I remember for feed rates on Reed's site was for rotifers, which can be a lot more prolific and voracious than copepods. I think I was looking at closer to 2mL of RGcomplete for a 3gal bucket (~10L usable vol) with a 20% harvest rate for 300k/day. There are other products in the RG series with much higher densities than RGcomplete if you don't mind adding the pH buffers and ClorAmX yourself. Rotifer Diet would be 0.6mL/day for the same harvest quantity. I need to find out the recommendations on RGcomplete, but the higher density products can be frozen.
I found some metered airless pump bottles that dispense 1mL/pump. Breaking up the larger portions into more manageable sizes and freezing may be the way to go. The space savings, reduction in work, and reduction in energy costs may be worth it. Especially if like me, you don't have the ability to work with cultures outdoors and don't have a lot of available space to dedicate to cultures (though I am working on developing a more energy efficient method for dense culturing of phyto and diatoms). Of course, this won't work if you need a motile algae or diatom, unless you go through enough to justify the concentrated products before they start losing too much of their nutritional value or start dieing off.

Reed's has a really good PDF on their Apocyclops culturing methods. They also mention the airlift harvester the the University of Florida developed.

I think that the version of those buckets that Tractor Supply carries is a bit more heavy duty and not that much more expensive.

If you are looking to get a larger starter culture, Reed's will work with you for that. Tie the order in with your LFS's order and you should be able to save on the shipping. Sustainable Aquatics and a few others should be able to work with you as well. Most would be willing to sell larger quantities in a bag. If you know when you are going to need them in advance, you can always scale up from a retail bottle. Add volume as the culture grows, which is pretty quick once things get going.

Good to know that Reed's can send larger Apocyclops orders

Anyhow, I am currently using 25 micron filter bags (these; https://www.ebay.com/itm/Dulytek-Premium-Nylon-20-Pcs-Filter-Bags-2-x-6-25-100-160-Micron-Mesh/133341703393?ssPageName=STRK:MEBIDX:IT&var=432744281001&_trksid=p2057872.m2749.l2649 ...they are intended for extracting oils from herbs) for harvesting brine shrimp and will soon use them for sorting walter worms by size. I have not had problems with flow rates on these...I have put one under my bathroom faucet at full throttle and it did not even begin to overflow (to use one as a harvester, I cut a soda bottle in half and use acryllic yarn to tie the filter bag to the end where the bottle cap is attached...I do one knot on one side of the bottle and one on the other so that I can remove the yarn to extract the contents of the filter bag). Apocyclops nauplii are about 70 microns in size (Reed did not specify the other dimensions).

The apocyclops PDF on Reed's mariculture recommended using 6 ml RGcomplete a day for a 15 gallon culture with 5 adult copepods per ml. I may build the airlift harvester, but I want to experiment with simply using a 1/4" ID piece of silicone tubing with a 100 micron filter bag (of the same brand as the 25 micron one I am currently using) tied to the end in the culture to selectively harvest the nauplii. As for feeding, the closely related Apocyclops royi can apparently synthesize its own DHA (see here; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6398464/ ), so it seems likely that A. panamensis (which has very similar habitat preferences) has a similar ability; I am thinking of trying to grow Apocyclops on common algae powders, such as cracked cell Chlorella powder, Dunaliella salina powder, and astaxanthin powder (actually whole cracked cell Haematococcus pluvialis powder). I was thinking of adding to that seaweed powder or even 5-50 micron golden pearls (A. panamensis will eat animals as large as juvenile rotifers, which are larger than 50 microns).

I do not know whether adult A. panamensis pose a threat to fry...I have read of A. dengizicus hunting sick baramundi larvae (but not healthy ones), but that species reaches well over a millimeter in size as an adult and is thus much larger than A. panamensis.

 

[ThRoewer]

Found this:
Culture Techniques of Marine Copepods

 

[LordJoshaeus]

Uh oh! The link did not work

 

[ThRoewer]

Uh oh! The link did not work

Try this one: http://eprints.cmfri.org.in/13376/1/Culture Techniques of Marine Copepods_2019.pdf

 

[ThRoewer]

Found a reasonably priced source for the screens:

Cut Mesh | Rosin Evolution

rosinevolution.com

They have food grade Nylon screen in 15 µm, 25 µm, 37 µm, 90 µm, and 160 µm, sold by the yard (39" wide).
The 37 should be about right for retaining the nauplii and the 90 µm is spot on to keep the adults out.

I can also report that the bucket method with green water works so far quite well to build-up the population. In my bucket culture (down-scaled Reed set up), the nauplii density is up significantly yet the algae still are not depleted.
My unaerated culture went up in density as well but not as much as the bucket so I transferred it to a bucket with air operated filter as well.

While I would love to use RotiGrow Plus, it would be cost-prohibitive to use it as the only feed. I think for my scale right now a mix of life algae (for the nauplii) and powdered algae (for the adults) and just some RotiGrow will have to do. I also feel that RotiGrow Plus might be a bit of an overkill as it is formulated to grow and enrich rotifers. But I don't think the copepods need enrichment with DHA and HUFA the same way as rotifers. As I understand it, copepods have on their own a far higher nutritional value than rotifers and Artemia.

 

[LordJoshaeus]

From what I've read, at least some Apocyclops species can enrich themselves with substantial amounts of DHA even when it is lacking in their diet. See this article on A. royi, for example; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6398464/

 

[ThRoewer]

My culture bucket with the air off to allow the nauplii to rise to the surface:




Got to chase down that Artemia...

And I will have to get busy building a nauplii trap.

 

[User]

So you guys are culturing pods, but harvesting the nauplii in order to feed larval fish babies?

Lol- I guess I should have checked what forum I was in first...

 

[LordJoshaeus]

So you guys are culturing pods, but harvesting the nauplii in order to feed larval fish babies?

Lol- I guess I should have checked what forum I was in first...

I'm not culturing them currently, but yes...that is the intention. Adult Apocyclops (and many other pods, for that matter) are similar in size or slightly larger than baby brine shrimp nauplii and thus are too large for most marine fish and invertebrate larvae at first; however, they produce nauplii that are often less than 100 microns long (significantly smaller than most rotifers) and these are the preferred prey of many marine larvae due to their sheer abundance and nutritional value. Sadly, culturing them en masse in captivity is not so easy...