Lake Bisina
Lake Bisina, also known as Lake Salisbury and Lake Bisinia, is a freshwater lake in eastern Uganda. It is a satellite lake of Lake Kyoga, which it drains into, and the two are to some extent directly connected by papyrus swamps. During the high-water rainy season, Lake Bisina can be up to deep and often directly connects with the smaller Lake Opeta, but during the dry season the two are clearly separated.
Conservation and ecology
Lake Bisina is one of Uganda's 33 Important Bird Areas and since 2006 a Ramsar-listed wetland of international importance.The lake is important for fish, notably several threatened haplochromine cichlids like Haplochromis orthostoma, H. argenteus, H. latifasciatus, H. lividus, H. martini, H. maxillaris, H. nubilus, H. parvidens, H. phytophagus and a number of undescribed species. Although Nile perch was introduced to Lake Bisina in the early 1970s, recent surveys have not detected this species, which has been implicated in the extinctions of many haplochromine cichlids elsewhere. A few tilapia species have also been introduced to Lake Bisina and they are still present, along with the native Singida and Victoria tilapias. Other, more widespread fish species found in Lake Bisina include marbled lungfish, and various species of catfish, African tetras and elephantfish.
Surveys of Lake Bisina’s aquatic plants recorded 15 vascular aquatic plant species plus Chara spp.. The same study mapped aquatic plant patterns across the lake and reported plant communities associated with depth and water clarity gradients.
Lake Bisina’s wetlands support specialist wetland birds. NatureUganda surveys note breeding activity and the conservation importance of papyrus and seasonally flooded wetland habitats in the Bisina catchment. A targeted survey report records the Fox’s Weaver as a highly range-restricted species linked to seasonally flooded wetlands in north-eastern Uganda, including Lake Bisina’s catchment and fringes.
NatureUganda baseline reporting highlights pressures from cultivation, grazing, wetland conversion and sedimentation as key risks to wetland functions and biodiversity in the Bisina–Opeta wetland system. Species-focused field reports also point to habitat loss and modification in seasonally flooded wetlands as a core threat for restricted-range wetland birds recorded in the wider Lake Bisina catchment.
Geography and hydrology
Lake Bisina lies about 15 km north of Kumi town and about 20 km east of Soroti. The lake covers about 192 km2 and sits around 1,050 m above sea level. It is surrounded by papyrus swamp and a broad floodplain linked to the Apedura River, which drains parts of Karamoja toward the lake system.The lake is shallow. In field sampling between February 2008 and August 2009, depths at sampling locations ranged from 0.6 to 5.0 m, with an average of 2.89 m.