Abstract:The jumbo flying squid () is a short-lived cephalopod species widely distributing in the eastern Pacific Ocean. Presently, international squid-jigging fishing vessels from China, Japan, Peru, and Chile target this species. China mainland started to exploit in 2001 and now has the largest squid fishery in the world. The oceanic waters off Peru are abundant and important fishing grounds. China has hundreds of fishing vessels operating in these waters, outside of the exclusive economic zones of Peru. The habitat is strongly affected by climatic and environmental variability at different spatial and temporal scales. In this study, two critical environmental variables[the sea surface temperature (SST) and sea surface height anomaly (SSHA) from 1950 to 2015] that affect the abundance and distribution of were used to calculate the habitat suitability index in the waters off Peru. We also evaluated the effects of El Niño and La Niña events on habitat suitability. The integrated HSI values were calculated by the Arithmetic Mean Method. The El Niño and La Niña years from 1950 to 2015 were defined by the 5-month running mean of the SST anomalies in the Niño 3.4 region (5°N-5°S, 120°-170°W) and measured by SSTs above or below a threshold of +0.5℃/-0.5℃ for 5 consecutive months. The intensity of each anomalous event was identified from the National Oceanic and Atmospheric Administration (NOAA). The results suggest that strong El Niño events, compared to weak and moderate El Niño events, are associated with warmer SST and higher sea surface height (SSH). These changes led to smaller suitable areas of SST and SSHA, thereby decreasing the suitable habitat range. During weak La Niña events, SST was warmer and SSH was higher, but during moderate and strong La Niña events, SST was colder and SSH was lower. The range of suitable habitats during strong La Niña events was significantly wider than that during moderate and weak La Niña events. Moreover, as the intensity of El Niño increased, the latitudinal gravity centers of the suitable habitat shifted southward, and as the intensity of La Niña increased, the latitudinal gravity centers of the suitable habitat shifted northward. Our findings suggest that there are significant differences in the environmental conditions of the squid fishing ground during El Niño and La Niña events. These differences directly affect the range of suitable habitats and spatial distribution of .