My friend had invited me along with him and his family to the ocean. It was vacation for the family, but for him and me it was the beginning of a week of serious business. We had an obsessive hobby to pursue. As avid and long-term freshwater fisherman, we were thrilled by the thought of catching those large and exotic saltwater fish we had seen on television a billion times before. Yet little did we expect there to be such vast differences between our freshwater fishing and the saltwater fishing, which we were about to pursue. We learned through trial and much error that in order to have a successful saltwater fishing experience we had to make adjustments to all the freshwater tackle, tactics, and gear we knew. Just as in any other sport, understanding gives rise to advantage and success. As serious fishermen, we had dedicated much thought to understanding the fish, hypothesizing their behavior. One understanding we had already gained through previous experiences was that fish readily eat the prey that is normally available. This, we concluded, was a sort of defense against fishermen and their foreign lures and was acquired through the fishes" own previous experience of eating a lure. In applying this understanding to our fishing, we performed a routine food chain analysis to find out what our lures needed to imitate. The results were that the part of the food chain just beneath our quarry consisted mostly of small fish such as anchovies and young yellowtail, smaller than those shad and bluegill normally eaten in freshwater ponds. To compensate for this difference we would have to use lures smaller than those we were used to using. Luckily we had some. With smiles on our faces we cast our wisely selected lures into the ocean, but we then encountered our first problem of saltwater fishing. Our lures wouldn't sink. As soon as they hit the water, the ocean current would just buoy them to the surface and, soon after, down current into the line of a nearby fisherman.