Did a couple ponds this past w/e locally. One being just over a ridge and closer to the cooling effects of the fog throughout the season. This is the pond. We chose this pic, NOT for the massive size of the piscatorial specimen, nor the visual of the submerged pier creating fine structure, nor the superbly fashionable shirt, but because dark (almost black) algea can be seen in the near shore weeds.

What is it? It is the first time I remember seeing it, and we have pestered denizens at this spot for over 40 years. It seems to start as a fine algea that clings to all the aquatic weeds and structure, seeming to smother a lot of stuff. I think it is not good. This pond seemed a bit slow. Top-water was be achieved, a BIT, through tenacious unwavering persistence. (read STUBBORNESS!)
10 minutes away, over one ridge, and just a bit further from the fog effects, we hit another pond and the residents drove us pleasantly insane with their top-water antics. Admittedly, the participants of this pond were sub 10", but one usually has at least one of these scaled by the "real" targets that reside there too.
Ya think the difference is due to water temps (no...did NOT check! ) or due to detrimental effects of the aquatic "black plague"?
.....lee s.