- International Seafood Sustainability Foundation" /> - International Seafood Sustainability Foundation" />
A fishing method used in the open ocean targeted to dense schools of pelagic tuna‑species. It consists of a large vertical net that is deployed around an entire area to surround the school of fish. The purse seine has floats along the top line and chains or weights at its bottom to allow the net to sink. Once the fish school is encircled, the net is closed underneath the school by hauling the purse line at the bottom of the net, which is called “pursing”. As the volume of the net becomes smaller, the fish become more concentrated and the catch can be finally scooped out using a brailer. Purse seines can also be used to catch fish congregating around a fish aggregating device (FAD), which can result in higher levels of bycatch.