The researchers studied the benthic polychaetous community in northern Kyeonggi Bay in September 1995. They found that benthic polychaetes were the most common group, with 60 species identified. The highest density of these creatures was in Yumha Channel near Incheon Harbor. The most dominant species was Heteromastus filiformis. The bay was divided into four regions based on species composition. The offsea/channel region had the most species, while Incheon Harbor had the highest density of benthic animals. The study suggests that pollution in Kyeonggi Bay, particularly in Incheon Harbor, has remained consistent over the past decade.