Abstract
Coral reefs are biodiversity hotspots which are heavily degraded by co-occurring anthropogenic stressors, including microplastics (MPs) and oil pollution. MPs and oil have been found to form aggregates, via adsorption of oil onto MPs. MPs may therefore act as a vector for heightened oil uptake into planktivorous fish, which are known to ingest MPs, though the impacts of these aggregates remain unassessed on coral reef fish. The present study experimentally investigated whether exposure to one of three treatments (“clean” microplastics (MPs), oil-weathered microplastics (OWMPs), and controls (no plastic)) had an ecological impact on the recruits of a common tropical damselfish Pomacentrus amboinensis (the Ambon damselfish). Polystyrene MPs were weathered in either seawater (MPs) or crude oil WAFs (OWMPs), to reflect MP pollution occurring in coral reefs with and without oil pollution. Exposure to clean MPs and OWMPs was shown to reduce the in-situ antipredator-behaviour and survival over time of Pomacentrus amboinensis recruits, with the greatest reductions observed in recruits exposed to OWMPs. Damselfish may therefore incur altered antipredator-behaviour and reduced survival when exposed to co-occurring MP and oil pollution, which may impact the commercially important species that damselfish act as prey for, as well as the wider coral reef ecosystem.