I don't know the answer but I have some suspicions based on my own forage pond experience.

It appears that you are about 4 ft. low. However, that doesn't stop fish from reproducing and tilapia are among the most prolific of fish. It is possible and I think highly probable that the tilapia have overstocked themselves and are living in a cesspool of their own making. You may have an external factor that is affecting your water quality. Take a look at the thread started by Condello regarding Carrying Capacity.

I've done the same thing but not with tilapia. My problem was a small forage pond with BG and fatheads. I quit seining but the fish didn't stop reproducing. Nor did any rain come. Too many fish fouled the water with their manure and everything died. Aeration may have helped but, like you, my ponds are a long way from power.

Tilapia have been called a miracle fish by some here. They are a good tool but only if there are enough predators, including the pond owner, to keep them cropped and enough rain to freshen the water. Those of us in arid climates need to think twice about these highly prolific tools. I'm scared to mess with them. The possible penalties, to me, are just too great.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP Grandpa