I've dived Poole Bay rock patches for over 30 years and have always found them clean and covered with marine life. The small fry on these rocks need food as well as shelter to develop and grow, which they find in amongst the tube worms, anemones, soft corals, weed, algae and hiding holes. These things are the start of the food chain which ultimately supports the bream, bass and Pollack, so if there is now nearly an inch of silt covering them this sounds like a environmental disaster.
Unfortunately as most of the patches are around the 10 metre mark, only tidal flow will have an impact in dispersal and I have no idea how long this will take. A good blow won't change much unless we get wave heights in excess of 5 metres.
Gordon H