Marine protected areas ineffectively protect seagrass and coral reef fish communities in the Phu Quoc and An Thoi archipelago, Vietnam

Abstract

Abstract The Phu Quoc marine protected area (MPA) is a multiple‐use MPA that was established in 2007 and is a component of Vietnam’s National MPA System. The MPA is divided into two spatially separated zones based on habitat type: a seagrass zone and a coral reef zone. In this study, visual census data were collected in 2018–2019 and were used to derive fish biomass and community diversity metrics as proxies for ecosystem condition and function (trophic and mobility). The effectiveness of the MPA in protecting fish communities in the seagrass and coral reef zones was evaluated. An updated characterization of the Phu Quoc fish communities, and an assessment of fish community variation among regions and between habitat types, is provided. In total, 125 species representing 74 genera of 40 families were recorded. Omnivores were the most abundant (38%), followed by planktivores (24%), whereas piscivores (2%) were scarce. There was an especially low density of high‐value fishery target species such as Haemulidae (<0.01%), Carangidae (<0.2%), Lethrinidae (<0.3%), Lutjanidae (<0.4%), Serranidae (<2%), and Chaetodontidae (<3%). Alarmingly, fishes with a total length of >20 cm only accounted for 1% of the total individuals. Species and functional composition were similar between protected and unprotected areas but differed among regions and between habitats. These results suggest that the protection of fishes provided by Phu Quoc MPA at the time of this study was ineffective. The taxonomic composition of fish communities has remained relatively unchanged over the last approximately 25 years, with the density of large fishes and commercial species remaining low. There is capacity to improve MPA performance by providing adequate resources for threat management and using evidence‐based decision‐making in management. The 2020 rezoning and expansion of the Phu Quoc MPA is discussed with regards to prioritizing biodiversity and coverage targets.