Lake Bermin is a small lake in the volcanic chain

Cameroon line

The Cameroon line is a chain of volcanoes.It includes islands in the Gulf of Guinea and mountains that extend along the border region of eastern Nigeria and western Cameroon, from Mount Cameroon on the Gulf of Guinea north and east towards Lake Chad....

 in the Southwest Region of Cameroon

Cameroon

Cameroon, officially the Republic of Cameroon , is a country in west Central Africa. It is bordered by Nigeria to the west; Chad to the northeast; the Central African Republic to the east; and Equatorial Guinea, Gabon, and the Republic of the Congo to the south. Cameroon's coastline lies on the...

. It is a volcanic lake with a crater rim that rises to a height of about 150 feet (45.7 m). This highly isolated lake is roughly circular in shape, lacks an inflow, but has an outflow into the Cross River

Cross River (Nigeria)

Cross River is the main river in southeastern Nigeria and gives its name to Cross River State.It originates in Cameroon, where it takes the name of the Manyu River....

 system.

Despite its very small size, it supports 9 endemic species of tilapiine cichlid

Tilapiine cichlid

The Tilapiini is a tribe within the family Cichlidae commonly known as tilapiine cichlids. Most of the taxa herein are called "tilapias", a diverse and economically important group containing the genera Oreochromis, Sarotherodon and Tilapia. A number of smaller genera, such as Alcolapia, Danakilia,...

 fishes (T. bakossiorum

Tilapia bakossiorum

Tilapia bakossiorum is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, T. bemini

Tilapia bemini

Tilapia bemini is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, T. bythobates

Tilapia bythobates

Tilapia bythobates is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom ....

, T. flava

Tilapia flava

Tilapia flava is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, T. gutturosa

Tilapia gutturosa

Tilapia gutturosa is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, T. imbriferna

Tilapia imbriferna

Tilapia imbriferna is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, T. snyderae

Tilapia snyderae

Tilapia snyderae is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, T. spongotroktis

Tilapia spongotroktis

Tilapia spongotroktis is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

, and T. thysi

Tilapia thysi

Tilapia thysi is a critically endangered species of fish in the cichlid family. It is endemic to Lake Bermin in Cameroon. It is threatened by pollution and sedimentation from human activities, and potentially also by large emissions of carbon dioxide from the lake's bottom .-Source:* World...

). This number of endemic fishes per area is the highest recorded anywhere. Genetic

Genetics

Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....

 evidence suggests that these probably were the result of sympatric speciation

Sympatric speciation

Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap or are even identical, so that...

. All are critically endangered

Critically endangered

Version 2010.3 of the IUCN Red List of Threatened Species identified 3744 Critically Endangered species, subspecies and varieties, stocks and subpopulations.Critically Endangered by kingdom:*1993 Animalia*2 Fungi*1745 Plantae*4 Protista-References:...

 by pollution

Pollution

Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...

 and sedimentation

Siltation

Siltation is the pollution of water by fine particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments, and to the increased accumulation of fine sediments on bottoms where they are undesirable...

 from human activities, and potentially also by large emissions of carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 (CO₂) from the lake's bottom (compare Lake Nyos

Lake Nyos

Lake Nyos is a crater lake in the Northwest Region of Cameroon, located about northwest of Yaoundé. Nyos is a deep lake high on the flank of an inactive volcano in the Oku volcanic plain along the Cameroon line of volcanic activity...

).