Abstract:The genus Lucifer is a type of macro-planktonic crustacean and serves as a food for various fish species. Some Lucifer species can be an indicator species for fishing grounds. Utilizing data from six sampling investigations conducted annually from 2016 to 2021 in the Pearl River estuary during August, this study investigated the relationship between the distribution characteristics of Lucifer hanseni and water masses and explored the adaptability of L. hanseni to temperature and salinity. The results showed that the average abundance of L. hanseni varied from 9.26 to 31.09 ind/m3 , with the index of clumping between 57.00 and 236.32, indicating a strong spatial aggregating distribution. According to K-means cluster analysis of water temperature and salinity, the survey region could be divided into three water masses: runoff, brackish-mixed and high-salinity water. L. hanseni is mainly assembled in the south area of Lantau islands, which is characterized by high salinity, and spread northerly to the runoff and brackish-mixed water. The spread range, with the northernmost distribution area near Humen, was determined by the strength of high-salinity water and the abundance of L. hanseni. L. hanseni was generally recognized as a warm water species, which is corroborated by the results of this study. The average abundance and number of distribution stations of L. hanseni in each investigation were significantly positively correlated with the average sea surface temperature. Previous studies presented varying results on the salinity adaptability of L. hanseni. L. hanseni was previously regarded as a nearshore-, offshore-, or estuarine low-salt species. In this study, positive correlations were observed between the abundance of L. hanseni and sea bottom salinity (SBS) in most surveys. The highest abundance was consistently noted within the salinity range from 29.5 to 31.0, implying that the distribution pattern of L. hanseni was closely related to SBS in the Pearl River estuary during the summer. In conclusion, L. hanseni was a nearshore species.