A circle hook is a fishing hook whose barbed point curves perpendicularly toward the shank. In conventional hooks, or J-hooks, the hookpoint runs parallel with the shank. When a circle hook is swallowed into the stomach of a fish, its circular design keeps the hook from penetrating vital organs until the fish turns, at which point the hook slides up toward the point of resistance, the fish’s jaw, and becomes embedded.
A circle hook prevents a caught fish from becoming gut- or throat-hooked, which commonly occurs with J-hooks. The mortality rate of fish caught with circle hooks is lower than with conventional hooks, an important consideration of catch-and-release practice, or releasing caught fish unharmed. Circle hooks are popular with fishing novices because fish are hooked by their own momentum, rather than the angler setting the hook. Although J-hooks hook more fish, more fish are landed with circle hooks.
Fishermen through the ages have used circle hooks. In Latin America, Pre-Columbian Indians used circular-shaped hooks made of seashell; in ancient Japan, fishermen used reindeer horn to fashion curve-shaped hooks; Pacific coast Native Americans also used hooks that were not unlike circle hooks used today. In modern times, circle hooks have been a tool of the commercial longline fishermen for decades.
Circle hooks primarily are used with live or dead bait. When baiting your hook, avoid burying the hookpoint into the bait, which would prevent it from catching on the fish’s mouth. The Cardinal rule when fishing with a circle hook is don't set the hook . After the fish has swallowed your bait, allow the fish to swim and create tension on your line. When you feel the fish tug on your line, again, do not set the hook. Instead, begin reeling. As the fish turns away from the line because of the slight tension you’ve created, the hook will slide into the fish’s mouth and hook itself. After landing the fish, you can remove the hook using a simple twist using needle nose pliers or with a dehooking device.
To get a literal feel for how a circle hook works, tie a length of monofilament line to a circle hook and grasp the hook inside your palm. When pulled straight up, the hook will slide out of your hand unimpeded. However, when the line is pulled to either side of your hand, the hook will slip along your hand and as it comes out of your hand, it will start to hook it.