In this study, we estimate the interannual spatial and temporal distributions of fishing grounds at night in the East Sea based on satellite and in-situ data. We observe that the 15℃ thermal front moves in the north-south direction according to the movement of the warm water (above 18℃) in the Tsushima Warm Current (TWC) area, forcing the cold water area (below 10℃) to either expand or shrink. The interannual variations of sea surface temperature (SST) in winter represented by the indicator SST of 6℃ are consistent with the east-west zonal areas in the central East Sea which represented over 1℃ standard deviation of SST in February during 1990-2000. Annual SST in the fishing grounds of common squid fishing vessels, observed both by fishing vessels and satellites range from 9-22℃, with the satellite-observed data having a larger range than the fishing vessel-based ones. The interannual distributions of the common squid fishing grounds in the East Sea are mostly concentrated in the TWC area in the southwestern part of the East Sea and in the coast of southern Honshu and Hokkaido in Japan. The interannual distributions of the nighttime fishing vessels are consistent with the catches investigated from the fishing vessel.

Abstract
 1. Introduction
 2. Materials and methods
 3. Results and discussion
  3.1. Temporal and spatial distributions of SST
  3.2. Distributions of SST, squid catches and nighttimefishing vessels
 4. Conclusion
 References

• Sang-Woo Kim(Fisheries Resources and Environment Division, East Sea Fisheries Research Institute)
• Jin-Wook Lim(Fisheries Resources and Environment Division, East Sea Fisheries Research Institute)
• Hee-Dong Jeong(Fisheries Resources and Environment Division, East Sea Fisheries Research Institute)
• Jong-Hwa Park(Fisheries Resources and Environment Division, East Sea Fisheries Research Institute)
• Ji-Suk Ahn(Fishery and Ocean Information Division, NFRDI) Corresponding author