Prangers are very effective on all fish in southern Australia. With 20 odd years diving with AUF clubs i have taken jew, snapper, king, black king, tuna etc. Only draw back is you need to get hone your skills to get closer and place a good shot when using prangers. Straight shafts you can shoot further away and a good body shot. The diver who shot the marlin at an alliman shield was Ted Lougher form north shore club, dived with the club for some 15 years. From memory it was some 40-60Kgs. one of three shot with pranger sin the sydney comp scene. Other memorable catches on prangers from the coral sea was a 50 Kg doggie by Gunter and a 75 KG by Paul Christey. In the early days of diving the coral sea we all used prangers. aim was a kill shoot or loose the fish and not you gear. For comp diving i prefer prangers, good in caves and close work.