Weather conditions for the site had been perfect for more than a week, so we travelled to Roa Island on Sunday 1st. April with high expectations of having a good interesting dive. Looking down on the water from the lifeboat gantry the conditions looked OK, so we kitted up and took the plunge.  Much to our surprise after we had covered only a few metres from the shore  the underwater visibility was no more than half a metre. It was quite light but there was very fine silt suspended in the water. As we progressed deeper it became more and more gloomy. At the deepest point (10.7m) in the middle of the channel it was completely dark and impossible to see anything. We swam slowly back up the slope to into shallower water, about (5m deep). here the bright sun penetrated the silty water a little more and the diverse marine life that we are used to seeing in the channel came into view. In the very small field of vision there were numerous species of crab, tiny anemones, sponges, common whelks, mussels and a small number of the  beautiful hydroid, Tubularia indivisa with tentacles extended. On returning to shore we  discovered that dredging operations were being carried out in the Channel and had been for a number of days.  This was the reason for the poor visibility and our far less than perfect dive. It was though the first of April !