It is dominated by thick rushes and is easily explored by canoe. Sugar cane is grown on the land to the north of the Upper Morass where the fertilizer and pesticide run off has polluted the river. In the Elim area, a tasty variety of African perch known locally as the 'Jesus fish' is being cultivated to help combat the overfishing of Jamaica's coastal waters. Its local name refers to the miracle of the multiplication of fishes because it is a prolific breeder. Also found in these swamps is the 'Jesus bird,' a jacana that wades among the floating leaves of aquatic plants giving the impression of walking on water.
Jamaican colloquialism is uniquely descriptive and frequently imbued with biblical references.
It is in this region of the Lower Morass that 'shrimp' fishermen can be found tending their trap baskets that are similar in design to those still used by fishermen on the Niger River in Africa and brought to the island by slaves over 300 years ago. Upriver, the YS Falls are a delightful contrast to the somnolence of the Lower Black River. The cool, clear water rushes over three levels for 120 feet to form one of the largest and prettiest waterfalls in Jamaica. Large pools at each level allow for a refreshing swim and are accessed by stairs alongside the river. The Lower Morass supports a rich environment of shallow estuaries, marshland and mangrove swamps.