Review of catch and effort for albacore tuna by Korean tuna longline fishery in the Indian Ocean (1965-2017)

This paper describes the fishing characteristics of Korean tuna longline fishery, with a focus on catch and CPUE trends for albacore tuna in the Indian Ocean from 1965 to 2017. The number of active fishing vessels showed the highest value in the mid-1970s, after that sharply decreased to 7 vessels in 2011 and 2012, while a slight increasing to 13 or 14 vessels in recent years. The albacore tuna catch peaked at about 10 thousand ton in 1974 and sharply decreased thereafter. Since 2009 it showed an increasing over 600 ton in 2013 and 2014 but decreased again in 2016. The CPUE of albacore tuna had a big jump in the early 1970s and showed a steady trend at a low level from 1980s to the early 2000s. However, it started to increase after 2003 and sharply increased from 2011 to 2014, but again decreased in 2016. And the main fishing ground of albacore tuna by Korean longline fishery was formed between 25°S and 45°S of the western Indian Oceans off South Africa and the eastern Indian Ocean off the Western Australia