One effective form of protection now being used in Chilean longline fishing for Patagonian toothfish is the so-called “umbrella system” in which the hooks are set in bunches shrouded by cone-shaped net sleeves that prevents birds from taking the bait when the longlines are dropped overboard.Although originally designed to reduce whale predation, the umbrellas have been very effective at reducing bird kills. Other measures include trailing aerial streamer lines to discourage birds from diving for trailing bait.