The pond has been full of needles and cones since we built it in 1996. There has never been a way to keep them out nor remove them all. When the wind blows and it blows often here in winter the yard and pond is filled with small branches, cones and needles. The debris you can see on the ground in front of the pond covered the entire back yard....
Until they disappeared without a trace winter 2007, I had many goldfish from 1996 happily swimming around. I blame a kingfisher or heron for the disappearance. There were no bodies, no fins, no bones, nothing.