Bill, thanks for bringing up this subject again. We use circle hooks almost exclusively. They have reduced our immediate catch and release mortality to essentially zero. We have no way to measure long term mortality. We normally use fathead minnows for bait and worms only occassionally. Most of the people fishing our lake have little to no experience.
Some things that I've noticed agree with what Bill said. I look at every hook to make sure the point of the hook lines up exactly with the shank. If it doesn't, the hook will catch deep in the fish's throat. After awhile, the opening of the hook might bend open and you end up with a regular "J" hook. If the point of the hook doesn't line up or the hook opens up, I bend the hook back into shape with a needlenose pliers. We normally use #6 hooks. If we can't find circle hooks, I get #4 eagle claw hooks with leaders and bend them into circle hook shape.
Circle hooks are great for kids using worms for bluegills. For experienced fishermen fishing for bass, they can be extremely frustrating.
