Site description A very large, isolated, chloro-carbonate alkaline lake, the northernmost and by far the largest of the chain of Rift Valley lakes in Kenya. The Omo river delta at the extreme northern end of the lake lies within Ethiopia (IBA ET069). Turkana’s water is brackish, but drinkable, and the lake holds freshwater fish. The c.600 km of lake shore vary greatly in substrate, from rock (most of the southern sector, the central eastern shore, and North, Central and South Islands) to pebble, sand (most of the north-western shore, and patches elsewhere) and mud (at Loiyengalani, El Molo and Allia Bays, the Omo delta and the inlets of the Turkwel and Kerio rivers). Beds of the submerged plant Potamogeton pectinatus occur in the most sheltered muddy bays. The country surrounding the lake is semi-desert with sparse vegetation: annual rainfall averages less than 250 mm (substantially less in some places), and it may not rain for several years at a stretch. South and Central Islands are National Parks and, in the north-east, c.13% of the shoreline is protected within Sibiloi National Park.
Key Biodiversity See Box for key species. Turkana is an extremely important waterbird site: 84 waterbird species, including 34 Palearctic migrants, have been recorded here. Over 100,000 Calidris minuta may winter, representing more than 10% of the entire East African/South East Asian wintering population (cf. Rose and Scott 1997). As well as supporting many wintering Palearctic migrants, the lake is a key stop-over site for birds on passage. Waterbirds are distributed all around the lake, but the highest densities are on mud and pebble shores; particular concentrations occur in sheltered muddy bays and the Omo delta. At least 23 species breed here, including Ardea goliath, and up to 50 pairs of the regionally threatened Rynchops flavirostris have bred on Central Island (but have now shifted to less disturbed localities). Other regionally threatened species include Casmerodius albus (occurs in small numbers, with 60 estimated in February 1992); Ephippiorhynchus senegalensis (nine estimated in February 1992) and Circaetus cinerascens.
Non-bird biodiversity: Lake Turkana is rich in fish, with 47 species, seven of which are endemic. The sheltered muddy bays with beds of waterweed Potamogeton are important for fish spawning. The fish in turn support a large population (estimated at some 14,000 in 1968) of Crocodylus niloticus.