I have had that condition on my pond on and off all spring, especially after I fired up my aeration and added dye. I'm no expert on this but I think what you have is a crop of phytoplankton algae on its last leg. Here's my reasoning.
Algae has a hard time living and growing in water that is high in DO. As your Oxygen content grows with circulation the algae starts to die off some and rises to the surface in the form of that scum. It usually looks like a sheen of oil on the water until the wind stacks it up. It will eventually decompose and sink over time.
That being said, just to make sure, if you can touch it and it seperates,like oil on water, then it is likely pollen. It's hard to tell them apart sometimes just looking at it.
Either is an unsightly mess and can make you concerned, but so far, I havent seen any ill affects on the fish. It will eventually clear up, but you can expedite the process with a little copper sulfate sprayed over it. If it turns brown quickly, its algae. If not...pollen.
If it starts turning a bright green and has an acidic smell, then you have a real problem with blue green algae and it needs to be dealt with as it is toxic. Copper sulfate will kill it, but be cautious on how big an area you treat. I wait for it to stack up and just spray the thickest part, wait a few days for the wind to do its thing, then spray it again. It will destroy any DO in that area, but your fish can move to good water.
.10 surface acre pond, 10.5 foot deep. SW LA. The epitome of a mutt pond. BG, LMB, GSF, RES, BH, Warmouth, Longear Sunfish, Gambusia,Mud Minnows, Crappie, and now shiners!!...I subscribe!!