It is the yellowish green gland under the gills. After cooking, discard the cooking water. If you decide to release your catch, use special equipment such as artificial lures or barbless hooks, or crimp the barb on a standard hook. These devices make it easier to remove the hooks from the fish. Follow these tips to safely return the fish to the water.
Time is essential, so quickly land and release the fish.
Keep the fish in or over the water as much as possible. Gentle handling of the fish is essential. Hands should be kept wet at all times while handling the fish. Do not put fingers in the gills or eyes. Remove hooks quickly using longnosed pliers.