THE SPATIAL DISTRIBUTION OF ANGUILLA JAPONICA AND ANGUILLA MARMORATA IN THE PEARL RIVER

This study analyzed the resources status and spatial distribution of Anguilla japonica and Anguilla marmo-rata in the Pearl River based on the data collected from 2015 to 2017. A total of 41 Anguilla japonica individuals with the average age of (4.2 ± 1.3) years were collected in these three years, and 93% individuals were sexually immature. A total of 12 Anguilla marmorata individuals with the average age of (4.3 ± 1.0) years were collected and 83% individuals were sexually immature. Anguilla japonica could migrate to the Heshan section of the Hongshuihe River with the percentages in individuals and in weight both less than one percent. Anguilla marmorata could migrate to the Shilong section of the Xijiang River with an occurrence rate less than one in 200. This indicated that the wild Anguilla spp. resources in the Pearl River are extremely rare and need to be protected. Redundancy analysis shown that river fractals and river width play important roles in spatial distribution for Anguilla japonica, while river width and river depth play important roles for Anguilla marmorata. This study is a part of a long-term investigation for the wild Anguilla resources of the Pearl River, and the results could be instructive to the conservation and management of Anguilla resources.