The Black River is Jamaica's longest river. Its name refers to the darkness of the river bed that has been lined with thick layers of decomposing vegetation. Over 100 species of birds have been recorded in the Black River morass.
It begins as an underground stream in the Cockpit Country and emerges north of Siloah on the southern border of the Cockpits. The river flows into the Upper Morass where the waters merge with those of the Smith River and other smaller tributaries. It is dominated by thick rushes and is easily explored by canoe.
The Black River Lower Morass is the largest freshwater wetland ecosystem in Jamaica and the Caribbean. It is a biologically diverse and extremely complex natural wetland ecosystem that supports a large number of plants, animals and natural communities. The wetland is traversed by the Black River. It is fed by three rivers, the YS, Middle Quarters and Broad Rivers.
The need for protection of this area has become critical as threats have increased drastically (pollution from agriculture, aquaculture, industrial activities, and tourism).
The above information taken from the following web sites where further information can be found.