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Daphnia culture faulure

Started by Guest_Moontanman_* , Jul 24 2014 02:06 PM

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16 replies to this topic

#1 Guest_Moontanman_*

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Posted 24 July 2014 - 02:06 PM

I'm having problems with my daphnia culture, it's in a 350 gallon + or - fiber glass tank and it always produces far more daphnia than i can use but since the recent rains daphnia production has dropped to almost nil.

I let rain water over flow the vat for water changes and i feed them a yeast sugar mixture five gallons at a time but the last week as seen the yeast vanish over night but daphnia yields are very low, not enough even for one breeder tank of black bands. The sides of the vat are covered by what looks like a detritus layer but that is algae and dirt and is always present.

I can't see any hydra which isn't really surprising as bad as my eye sight is these days but I am pretty careful not to introduce materials that might have hydra but that doesn't mean they have't found a food hold.

Any thoughts, suggestions?

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#2 Guest_gerald_*

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Posted 24 July 2014 - 03:06 PM

I dont why they crashed, but every Daphnia culture does crash eventually. Maybe it's due to successional changes in the mix of phytoplankton, with a shift toward species that are bad-tasting, non-nutritious, or toxic to Daphnia. Keeping multiple containers going and restarting periodically when production falls off may be a better strategy than relying on one big permanent culture.

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#3 Guest_dac343_*

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Posted 24 July 2014 - 03:07 PM

pH drop from rain water? Not enough calcium to be a buffer might be a possibility as well. pH drops tend to be a big killer in daphnia and moina cultures. Did you have any crushed coral or something similar in there?

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#4 Guest_Skipjack_*

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Posted 24 July 2014 - 08:55 PM

I dont why they crashed, but every Daphnia culture does crash eventually. Maybe it's due to successional changes in the mix of phytoplankton, with a shift toward species that are bad-tasting, non-nutritious, or toxic to Daphnia. Keeping multiple containers going and restarting periodically when production falls off may be a better strategy than relying on one big permanent culture.

Like Gerald said. The key is keeping multiple containers with greenwater, so that you have plenty of daphnia food, and your culture is spread out. Rotate them. You will still have crashes, but will still have plenty to keep it all going. When I was culturing daphnia, I was using kiddie pools. I had 7 and rotated them regularly. I also used a bit of miracle grow here and there to maintain fertility. I was able to harvest well over a quarter cup a day. May have been more.

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#5 Guest_Kanus_*

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Posted 25 July 2014 - 07:53 AM

The first thing that comes to mind for me is a calcium deficiency if the water is primarily replenished by rain. Daphnia are crustaceans so, like crabs, their shell is made of calcium carbonate. They need at least some mineral hardness to grow and reproduce.

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#6 Guest_Skipjack_*

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Posted 25 July 2014 - 11:25 AM

The first thing that comes to mind for me is a calcium deficiency if the water is primarily replenished by rain. Daphnia are crustaceans so, like crabs, their shell is made of calcium carbonate. They need at least some mineral hardness to grow and reproduce.

That is a good thought. It is hard to say though if calcium is the problem, or if this is just a regular daphnia crash. This kind of goes hand in hand with what David said.

Add some calcium.

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#7 Guest_centrarchid_*

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Posted 25 July 2014 - 09:48 PM

For parallel cultures I suggest using 55-gallon plastic barrels. To get away from complexities of managing phytoplankton as forage. consider using a detritus based forage. Phytoplankton likely superior with respect to nutritional quality but also more fickle.

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#8 Guest_Moontanman_*

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Posted 26 July 2014 - 11:26 AM

Well I am hip deep in daphnia again, I've been off line for three days but I added about a half pound of calcium chloride and 15 gallons of bread yeast I mix up with sugar and let set for several hours. They're back! Thanks for the advice guys... got lots of blood worms in the vat as well..

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#9 Guest_Moontanman_*

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Posted 26 July 2014 - 07:01 PM

Ok guys another thing, tadpoles in my daphnia tank good, bad, or no matter?

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#10 Guest_Skipjack_*

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Posted 26 July 2014 - 07:13 PM

http://tadpolepond.com/?page_id=4

Surprise to me but it looks like they may not only compete for food, but even prey on your daphnia. I have a hard time imagining a tadpole being able to chase down anything, but I guess I am wrong.

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#11 Guest_Moontanman_*

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Posted 26 July 2014 - 07:24 PM

http://tadpolepond.com/?page_id=4

Surprise to me but it looks like they may not only compete for food, but even prey on your daphnia. I have a hard time imagining a tadpole being able to chase down anything, but I guess I am wrong.

I'll have to dip them out, they might be bullfrog tadpoles, one was in my vat the other day, not sure how a toad could jump 30 inches...

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#12 Guest_Skipjack_*

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Posted 26 July 2014 - 07:45 PM

I would assume tree frogs of some flavor. Probably won't get large enough to do much damage before they morph, but that is only a guess. Fairly easy for a pair of tree frogs to climb in there and breed, quite coincidental for two bullfrogs to wind up jumping 30 inches into the same tub and breeding.

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#13 Guest_gerald_*

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Posted 28 July 2014 - 12:07 PM

I dont think tadpoles have much effect on Daphnia. They eat mainly attached algae, while Daphnia eat free-floating planktonic algae. They might even be beneficial for that reason. You can distinguish Hyla (treefrogs) from Rana (true frogs) tadpoles by the dorsal fin attachment -- it extends farther up the back on treefrogs. Also our NC treefrogs will metamorphose when the head-body is less than 1" long. Green frog and bullfrog (Rana) tadpoles are mostly bigger than 1" when the legs appear.

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#14 Guest_Moontanman_*

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Posted 28 July 2014 - 08:13 PM

I dont think tadpoles have much effect on Daphnia. They eat mainly attached algae, while Daphnia eat free-floating planktonic algae. They might even be beneficial for that reason. You can distinguish Hyla (treefrogs) from Rana (true frogs) tadpoles by the dorsal fin attachment -- it extends farther up the back on treefrogs. Also our NC treefrogs will metamorphose when the head-body is less than 1" long. Green frog and bullfrog (Rana) tadpoles are mostly bigger than 1" when the legs appear.

I caught them all and put them in a small wading pool I had set up, I'm feeding them fish food, we can always use more frogs!

My daphnia culture is back to normal, I harvest about a half cup once a day it doesn't seem to have any effect on their numbers.

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#15 Guest_dac343_*

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Posted 28 July 2014 - 08:29 PM

I say leave the tadpoles in with the daphnia, it will help lessen the chance of bd infection in the frogs

(I'm not totally serious about doing so but there has been some research on it http://www.the-scien...Killing-Fungus/).

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#16 Guest_Moontanman_*

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Posted 28 July 2014 - 08:47 PM

I say leave the tadpoles in with the daphnia, it will help lessen the chance of bd infection in the frogs (I'm not totally serious about doing so but there has been some research on it http://www.the-scien...Killing-Fungus/).

Too late, already moved them, I am pretty sure they are toad tadpoles, I figured out how they could get in my daphnia vat. I still have a big bull frog visiting the vat, I love to listen to them at night, I grew up listening to bullfrogs call in the night, I could hear them from over a mile away...