We just found this photo when looking through some of the older pictures from the trip. It was taken on our first evening at La Jolla (just North of San Diego) along with a number of pictures taken at sunset that evening.
In the preceding picture the man fishing looks solid enough (he appears as a silhouette), but in the picture shown here it appears that you can see right through the man (particularly the edge of the rock seen through his legs). The photo has not been edited or manipulated in any way. I have uploaded a copy of the picture file (unreduced in size and unaltered) in which you can zoom in on the man to see the full effect - click on the picture here to open the full file.
Is it a ghost or is there another explanation?