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.

It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers