Anton Lamboj


Ecological conditions and fish diversity of the Upper and Middle Waanje River in Sierra Leone

Associate Researcher
Unit for Integrative Zoology, Department of Evolutionary Biology
University of Vienna

Lamboj A.1 & Mansaray A.2
1Department of Evolutionary Biology, University of Vienna, Austria.
2Department of Aquaculture and Fisheries Management, School of Natural Resources Management, Njala University, Sierra Leone.

The fish fauna and aquatic systems of Sierra Leone/West Africa are just poorly explored, even though the country offers a respectable biodiversity and unique habitats. However, and this probably has something to do with its lack of awareness, the country has been extremely isolated since the beginning of the 1990s, when at first a terrible civil war raged there from 1991 to 2002 and later on, a series of Ebola outbreaks hit the country. First new biological research started after this, about 10 years ago.

The Waanjie River is a medium-sized river that originates in the southern part of Sierra Leone. It has its headwaters in the central south of the country, in a hilly region near the town of Kenema. It has a total length of about 177 km before it joins the Sewa River near the coast and then flows parallel to the country's coastline for another stretch under the name Kittam, before it flows into the Atlantic Ocean in the Sherbro Estuary. The river's catchment area covers a total of about 4,510 km2.

Here the results of a four-year period, focussed on some water quality parameters and the exploration of fish diversity in the upper and middle parts of the river during several seasons are presented. In totality, the water quality parameter values in the areas studied were relatively uniform and in good condition, with slight disturbance by local people through fishing and some domestic activities. The parameters range from 35 to 56 uS, GH, and KH from 0° to 2°. The pH values were between 6.6 and 7.6, and the water temperatures were between 23.2 °C and 25.6 °C. A total of thirty (30) fish species with stable populations were recorded from the areas surveyed. Notwithstanding, there was a good difference in species abundance and diversity, with the upper reach recording fewer (7 species) and the middle reach recording the highest (29 species). Due to the good status of the river, conservation of the river is recommended.