Bacteria count too high?

[justin]

I'm in 'ka-hoots' with some biologist who work at KSU in Frankfort...They have a substantial aquaculture facility there and use portions of a waste water treatment plant for research and propagation (polyodon spathula).

One of the cooling basins is loaded with daphnia. Right now the pond is teaming with them; almost gives the water a red tint. I'm getting massive amounts of them and plan on using this as my initial food source for future P. waltl larvae. They don't seem to reproduce in my established tanks, but the bacteria count (outside of the filter) is significantly less than whats in the cooling pond.

Does anyone see any risk in using daphnia from this source? It's basically cooled and then released into the KY river which, of course, greatly reduces the bacteria count through dispersal. There is no further treatment, that is, before it is released.

I strain the daphnia and rinse them with 'clean' water before feeding them to my animals, and feel fairly good about my source. I was just wanting some input on what you folks think?

 

[paris]

arent daphnia considered too aggressive as a food item for small larvae? i keep my feeder animals in a separate self supporting tank and then use a pipette to remove small ones when they are needed or will just shake off some of the plants into the larval tank when bigger food is on the menu. my concern with wastewater treatment is what went into it-and im not talking about the brown matter! numerous chemicals are washed down drains daily (both legal and illegal substances) and also we are an over medicated nation and many of these compounds are not broken down by our systems and thus pass through still active, i worry about their effect on the animals-either as false hormones, unnecessary antibiotics or just as random manmade compounds that can do unknown things. daphnia isnt that hard to culture and ive done well with ostocods as a food source for small guys.

 

[alan]

I'd worry about chemical contamination. Otherwise, Daphnia are an indicator of relatively good water quality. Sifted Daphnia are a good food source for larvae. Some species of Cyclops (copepods) may be harmful on occasions.

 

[justin]

Yeah, I was thinking of all those things. I do know for certain this is the last stage before it's released directly into the KY River. I suppose it has passed the standard requirements for treated water before it's release.

They are absolutely loaded with daphnia and I know that the water quality must be pretty good considering the visible numbers. At least 'bioligically clean.'

I'm not 100%, but I thought daphnia are a great food source for larvae as well as adults? They survive for several days in my tanks before they are eaten (or sucked into the filter!).

Any hoot, thanks for the feed back.

 

[jennifer]

Daphnia are an excellent food for all larvae. I don't think they are a danger to larvae (maybe Paris is thinking of cyclops, some of which can be a bit vicious).