Foraminiferal-based biotic indices to assess the ecological quality status of the Gulf of Gabes (Tunisia): Present limitations and future perspectives

•Biotic indices based on benthic foraminifera are efficient tools to evaluate pollution in the Gulf of Gabes (Tunisia).•Indices based on epiphytic foraminifera reflect environmental conditions in seagrass meadows.•The Djerba Island considered as “pristine” seems also affected by pollution.