Mangrove ecosystems are known as productive ecosystems with high ecological and economic
importance. Anthropogenic effects have destroyed these habitats in many cases. Evaluating ecological
and environmental status help to find stress sources in order to conserve them against more destruction.
Present study was designed to evaluate ecological health status of Bidkhun mangrove swamp, Bushehr
province, Persian Gulf. This habitat is surrounded by industrial establishments and is affected by
discharge of urban sewage. Investigating macrofauna structure and calculating ecological indices
including Simpson, Shannon-Wiener, AMBI and M-AMBI, were performed to assess its ecological
integrity. Sampling was done in six stations during four seasons. Macrofauna and environmental
parameter were investigated. Totally 35 macrobenthic species where identified. Polychaeta was the main
taxa. There were special and temporal changes in macrofauna composition. Generally, station four, which
was located close to sewage canal opening, had different macrobenthic and environmental features. High
concentration of nutrients as a result of sewage discharge, have led to algal bloom and decrease of
macrofauna density, consequently. Ecological status of present habitat was good or high in most stations
but it was poor and very bad in station four. Ecological indices showed that this station is extremely
polluted. Besides, invasive freshwater reeds have surrounded the mangrove trees in mentioned station.
It is concluded that discharge of sewage is main source of habitat degradation for Bidkhun mangrove
swamp. Hence, it is necessary to decrease its impacts by sewage treatment or stopping sewage
discharge.