Bellamya (Bellamya crawshayi)
Bellamya crawshayi is classified as Endangered (EN) on the IUCN Red List (1).
Bellamya crawshayi is a large freshwater snail endemic to Lake Mweru in Central Africa, where it is threatened by global climate change (1). It is a member of the family Viviparidae, commonly referred to as the ‘mystery snails’, which have a worldwide distribution. These snails tend to have a large, spiral shell, with six or seven whorls and a thick lip. The shell is usually dark greenish with dark bands and has a thick, horny disc covering the opening (2) (3).
Bellamya crawshayi is endemic to Lake Mweru, which spans the border between Zambia and the Democratic Republic of the Congo (1).
A freshwater species, Bellamya crawshayi is found on sand and mud substrate in Lake Mweru (1).
Owing to its rarity, little is known about the specific biology of Bellamya crawshayi. However, snails of the family Viviparidae tend to be suspension feeders, lying for long periods in mud with the mouth facing upwards, using specialised gills to filter food particles from the water. They are also viviparous (2).
While the population of Bellamya crawshayi is currently thought to be stable, this species is endemic to a single lake that is rapidly decreasing in size as a result of environmental changes, including global climate change. Lake Mweru is increasingly drying out and becoming shallower, and may in fact be completely dry within the next 50 years. The lake is currently only around three metres deep on average, but when it reaches between one and two metres in depth, monsoon rains mix the mud and water, resulting in increases in salinity and a decrease in oxygen levels. Bellamya crawshayi is extremely vulnerable to these changes, which are already known to have caused the extinction of related species in other lakes (1).
Bellamya crawshayi has not been the target of any known conservation measures. Recommended actions for this species, as well as for other animals inhabiting Lake Mweru, includes population monitoring and research to determine how best to mitigate the threat of climate change (1).
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- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Viviparous: giving birth to live offspring that develop inside the mother’s body.
- Whorls: in animals, the spirals or convolutions in the shell of a snail. In plants, a set of leaves, flowers, or branches that spring from a stem at the same point and encircle it.