Status and temporal changes in reef fish communities in Hon Cau marine protected area, Binh Thuan province

Abstract

A study on the status and temporal changes in communities of coral reef fishes in Hon Cau Marine Protected Area was carried out at 12 reef sites in August 2020 in combination with the data from previous studies. A total of 351 species belonging to 128 genera and 45 families of coral reef fish were recorded. The average density in 2020 was 237.3 ± 82.8 individuals/100m2, mainly occupied with small-sized fishes (accounting for 86.8% of total density) and ornamental fish, with the dominant families of damselfishes, wrasses, and cardinalfishes, while the the large-sized fish accounts for a very low rate. Target fishes were found in very low density and dominated by herbivorous feeders (especially rabbitfishes). The area around Hon Cau Island have species diversity (accounting for 94.4% of total species recorded in 2020) and a density of reef fish compared to the Breda shoal and coastal areas. The analysis results show that there were three distinguished assemblages of reef fishes, in which the reef fish communities around Hon Cau Island are different from the shoal and coastal areas. After nearly ten years of establishing Hon Cau MPA, coral reef fish density is maintained relatively stable in the area around Hon Cau Island and significantly decreased in Breda shoal and the coastal areas. There is an increase in the density of herbivorous fishes, while the large-sized and inextricably linked to the coral reef (groupers, snappers, sweetlips, butterflyfishes) with very low or reduced densities over time.