Pacific bluefin tuna (Thunnus orientalis) has been mostly caught by the Korean offshore large purse seine fishery in Korean waters. The annual catch of Pacific bluefin tuna caught by the offshore large purse seine fishery in Korean waters showed less than 1,000 mt until the 1990s except for 1997. The catch sharply increased to 2,401 mt in 2000 and recorded the highest of 2,601 mt in 2003, but the catch has generally decreased with a fluctuation thereafter. The main fishing ground of Pacific bluefin tuna of this fishery is formed around Jeju Island. However, it expanded to the Yellow Sea, the coastal of Busan, and the East Sea, which depends on the migration patterns of Pacific bluefin tuna by season. The CPUE standardization of Pacific bluefin tuna was conducted using Generalized Linear Model (GLM) to assess the proxy of the abundance index. The data used for the GLM were catch (weight), effort (number of hauls), catch ratio of Pacific bluefin tuna, moon phase by year, quarter and area. The standardized CPUE from 2004 to 2011, except for 2003 and 2010, showed a steady trend, and then increased until 2014. The CPUE in 2015 decreased, and in 2016 was higher than that in 2015. The result of GLM suggests that the effect of the catch ratio of Pacific bluefin tuna is the largest factor affecting the nominal CPUE.

The global warming related to GHG (greenhouse gases) emissions from industries is a major issue globally. Furthermore, GHG emissions from the fishery industries also represent an important issue, as indicated by "The Code of Conduct for Responsible Fisheries" at the Cancun, Mexico, meeting in 1992 and by the Kyoto protocol in 2005. Korea pronounced itself to be a voluntary exclusion management country at the 16th IPCC at Cancun, Mexico, in 2010. However, few analyses of GHG emissions from Korean fisheries have been performed. Therefore, a quantitative analysis of GHG emissions from the major Korean fisheries is needed before guidelines for reducing GHG emissions from the fishing industry can be established. The aim of this study was to assess the present GHG emissions from the Korean Purse seine fishery using the LCA (life cycle assessment) method. The system boundary and allocation method were defined for the LCA analysis. The fuel consumption factor of the purse seine fishery was also calculated. The GHG emissions for the edible fish were evaluated by determining the weights of whole fish and gutted fish. Finally, the GHG emissions required to produce 1kg of whole fish and 1kg of edible fish were deduced. The results will help determine the GHG emissions from the fishery. They will also be helpful to stakeholders and the government in understanding the circumstances involved in GHG emissions from the fishing industry.

Korean large purse seine fishery catches chub mackerel, sardine, jack mackerel, Spanish mackerel, etc. which are mainly pelagic fish species. The proportion of chub mackerel was 60% over in Korean large purse seine fishery. Sea surface temperature (SST) increased 0.0253℃ per year and total rising rate was 0.759℃ from 1980 to 2009 in the southern sea of Korea, where is mainly fishing grounds of Korean large purse seine. It was that p〈0.01 level was statistically significant. It is northward movement that the center of fishing grounds of chub mackerel by Korean large purse seine fishery moved 4.57km/yr. It was rapidly northward movement about 7.1km/yr, 8.13km/yr to move Spanish mackerel and bluefin tuna fishing grounds. However, the fishing grounds of jack mackerel were moved further south in the 2000s than the 1980s. Catch of tunas and bluefin tuna consistently increased in Korean waters. There was a significantly positive correlation between SST and catch of bluefin tuna in the fishing grounds of Korean waters.