Salini is one of the last remaining salt marshes in the Maltese Islands. The former much larger marsh system of Marsa was reclaimed in the 19th century, rendering that of Salini the largest extant system. In the past the marshland used to be more extensive, covering areas now occupied by Kennedy Grove afforested site. Is-Salini is characterised by the intermixing of sea and fresh water, the latter originating from a complex of valley systems that drain into the area. This forms an estuary with salt marsh and fresh water vegetation. A canal runs on the left and to the right of the salt pans. This canal, known as Tas-Sokkorsu provides freshwater to the marsh. The estuary of Is-Salini is very dynamic and dependent on the accretion and deposition caused by dead sea grass foliage.
The salt marsh is very species diverse and the species composition at is-Salini is different from the other salt marshes in the Maltese Islands, since it is a mixture of fresh water elements and marsh species. This site supports a number of endemic flora and fauna as well as a considerably large number of rare, endangered and/or locally threatened species.
MEPA scheduled is-Salini as an Area of Ecological Importance and Site of Scientific Importance as per Government Notice No. 402/96 in the Government Gazette dated 25 June 1996.