the organ or part of a fish which takes oxygen out of the water and transfers the oxygen to the blood of the fish; usually located one each side at the place where the head becomes the body; and usually seen from the outside as a large curved slit in the side of the fish
– Respiratory organs used by aquatic animals to obtain oxygen from, and release carbon dioxide to, the surrounding water In oysters, they are the largest organ and consist of four folds In addition to respiration, oyster gills are directly involved in feeding by creating water currents, collecting food particles, and moving food particles to the labial palps for further sorting They also serve to separate masses of eggs released from the ovary during spawning into individual ova for efficient fertilization