Boilie a boilie is a hair rig (the bait is not attached directly to the hook) which allows the boilie to sit off the back of the hook. This not only means that the bait will behave more naturally in the water (for example when disturbed by feeding fish) it also will often make the difference between a good hook hold and a bad one. Due to the nature in which a carp feeds the bait is blown out of the mouth soon after it has been picked up and the fact that the bait can move independently from the hook
Catch and release lures are usually hooked cleanly in the mouth, minimizing injury and aiding release. Other studies have shown somewhat lower survival rates for fish gut-hooked on bait if the line is cut and the fish is released without trying to remove the hook. Catch and release is a conservation practice developed to prevent overharvest of fish stocks in the face of growing human populations, mounting fishing pressure, increasingly effective fishing tackle and techniques, inadequate fishing regulations and enforcement, and habitat degradation. Sports fishers have been practicing catch and release for decades, including with some highly pressured fish species. Opponents of catch