I believe what you are seeing are two things. A turbidity cause by the carp and the pea green algae bloom combination. The algae bloom is the basic food source that most want and fertilize their ponds to get it when they can see beyond 18 inches in depth. The pond filled the first year and the Israeli’s, KOI, and Channel Catfish along with bass, bluegill were put in early the second year. I'm sure the fish were hungry at first during the transition and eat any FA as it tried to form. There is no FA in the picture and hasn't been for the next 15 years except for traces around the pond edges, which is a good thing. The exception that I already mentioned was between the winter fish kill and before the plants were up. The poo from the fish caused a constant green bloom from then on for food production. And some turbidity from all the carp. Then add plants, plants attract bugs, etc. and you get even more food for all pond life and a lot of fish poundage for this 1 acre pond.
This picture is a friend with a large KOI pond that has a rubber liner so there is no turbidity in this pond caused by the KOI. The pond is maybe a fifth of a acre. You can see there is a pea green algae bloom so you can hardly see the KOI. But he doesn't have any FA. Now you can attribute that to the algae bloom but not completely I think.
II like to run experiments with my pond. Can a very clear pond produce lots of fish poundage if it doesn't have a pea green algae bloom and do this naturally. I think it can. In the early 30's my aunt and uncle fished on a small river bank in Canada and caught lots of really big northern pike they had strung on a rope tied between two trees. I wish I had that picture. I assume that water was crystal clear as the waters I have ever see in Canada. So how did that food chain work? It all had to started with plants. In the 50's I used to watch a TV program where a pro fisherman would fly into upper Canada and Antarctic and catch huge fish in clear waters on nearly every cast. In the expedition of Louis and Clark and the early settlers fish were everywhere. Anyway, sorry to write a book but I find this fascinating.
