A circle hook is a fish hook which is sharply curved back to form a circular shape. It is rarely swallowed by the fish, though if swallowed, it can be easily pulled back. What is so great about this type of hook is that it hooks the fish in the corner of its mouth and not harm the gills or the internal organs. Believe it or not, when the fish swallows the bait along with the hook, all you have to do is slowly reel it in and it will not harm the internal organs but will just catch the corner of the mouth.
When using a circle hook, hook the bait at its fleshy part, away from the bones. This way, the bait won’t be stuck on the hook and defeat the purpose of using a circle hook as the bones might gut-hook the fish or lacerate the internal organs of the fish.
A circle hook is, perhaps, the greatest tool for catch-and-release fishing.
Also, if you have tried fishing even once, chances are you might have hooked a fish that is below the allowed limits for that species and must be released. If you were using a regular hook, then you must have cut the leader so as not to do further damage to the fish. However, biologists say that these hooks often slash at or damage the internal organs, gut, or gills of the fish so that its chances of survival are slim even when released immediately.
What is so great about the circle hook is that it works well on unattended lines – the fish eats the bait with the hook, tries to swim away, and is hooked in the mouth.
Whether you are fishing on a catch-and-release system or just fishing for any kind of fish that is you might release for not meeting the standards, you should try using a circle hook. You’ll find it quite useful in catching a lot of fish and improving their survival rate upon release.