Catch and release is easily one of the greatest advancements in improving our fisheries over the last two decades. One of the things that has helped with the mortality rates of released fish in recent years is the use of circle hooks. These tend to hook the fish in the corner of the mouth and are far less likely to be swallowed.
In this piece from a decade ago Dr. Hal Schramm analyzed the growing use of circle hooks, especially for catch and release. They have become essential for saltwater and very popular for freshwater as well.
Even though the numbers for freshwater fish looked skeptical back then, Hal tried them and found success. He invited others to try their own experiments with them. One thing to keep in mind is that hooksets aren't as necessary, which may be a habit that isn't easy to break. What have you anglers out there found?