Development of a technique to estimate the horizontal distribution of lit fishing vessels in the East China Sea using satellite luminescence

Abstract

The East China Sea is a semi-enclosed sea, surrounded by Japan, China, South Korea and Taiwan, and is continuously influenced by lit fishing vessels overexploiting fishery resources. Quantitative analysis of this fishing activity is essential to sustainable resource management. Recent advances in satellite remote sensing technology, notably the introduction of the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite, which gathers luminescence data, have enabled the detection of lit fishing vessels operating at night. In the present study, we collected in situ observation data (ship radar images and visual observation data for lit fishing gear types) for the period when the Suomi NPP satellite passed over the East China Sea at night. The geographical position of each fishing gear type was extracted from the radar image and compared with the corresponding position of satellite luminescence in order to obtain the luminescence specific to each fishing gear type. We statistically analyzed the luminescence data to specify the luminescence range of each fishing gear type. The luminescence range of Chinese lit falling-net fishing vessels during nighttime fishing operations was distinguished from the ranges of other fishing gear types. We are now able to estimate the horizontal distribution of Chinese lit falling-net fishing vessels from Suomi NPP satellite luminescence, using its own luminescence range.