Pond Boss
Posted By: anthropic Shad and tilapia - 03/29/20 02:32 AM
Getting TFS Monday. I struggle to keep water green, must fertilize n lime to offset natural acidity. Question is, will TP munching algae help increase fertility, decrease, or have no impact?
Posted By: Snipe Re: Shad and tilapia - 03/29/20 03:01 AM
In theory, they will decrease fertility due to the fact they filter planktonic growth with gill movement.
Posted By: jpsdad Re: Shad and tilapia - 03/29/20 04:30 AM
It kind of depends on what you mean by the question. Will the presence of TP reduce phytoplankton abundance and increase the secchi depth? Probably, but this just redirects where primary production is going. In other words, the fertility isn't really lost because it is growing TP instead of things that TP compete with. So if you judge fertility by the biomass of zooplankton ... then the water is less productive for them in presence of TP. That said, it probably isn't best to judge fertility by the biomass of any particular class of consumer organism.

Three things are contributing to the fertility of your pond. Perhaps the most important is its phytoplankton production which is what your liming and fertilizer are for. The energy is derived from sunlight. The plant production powered by sunlight is the primary production. Now if all that production is consumed by the creatures that promote your goals then the fertility of primary production is highly efficient. The second factor contributing to the fertility of your pond is detritus. Again, if all the detritus were consumed then it would be running on high efficiency. In addition to these, feed also contributes to the ponds production and detrital stores.

TP are remarkable in that they are able to effectively use all three of these sources of food. Their use of things like FA and detritus increase the ponds production of fish even though they may reduce planktonic standing weights.

There is growing evidence supporting the proposition that grazing of primary producers does not reduce the primary production. Reasons for the maintenance of primary production under grazing isn't fully explained nor completely understood. A healthy and vibrant system has all the organisms, habitat, and water chemistry in place to efficiently graze or recycle primary production and detrital stores. TP go a long way as a graze and recycle primary consumer organism.
Posted By: ewest Re: Shad and tilapia - 03/29/20 03:14 PM
Good question.

This link is to a thread about energetics - an add on to jpsdads comments above.

http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=126776&page=1

Energy in (sunlight is the source) = energy used (biological activity) + growth.

If the question is can you have both TP and TFS in your pond the answer is likely yes but its level of success will depend on your management activity and at your location the winter weather.

Posted By: anthropic Re: Shad and tilapia - 03/29/20 11:53 PM
Thanks for those comments! Not a simple answer, as is so often the case.
Posted By: Pat Williamson Re: Shad and tilapia - 03/30/20 12:40 AM
So y’all are saying that tilapia filter feed like threadfin shad?
Posted By: anthropic Re: Shad and tilapia - 03/31/20 04:34 AM
.my understanding is that TP focus on algae.
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