Aphanius saourensis extinct in the wild

Only Critically Endangered freshwater fish species of North Africa likely to be extinct in the wild

Mahmoud Bacha & Jörg Freyhof

The freshwater biodiversity of North Africa has been assessed against the IUCN Red List criteria in 2010 (García et al., 2010). With 27 % threatened freshwater fish species, their status is surprizingly good for such an arid area. Only one species, Aphanius saourensis, had been assessed as Critically Endangered.

Aphanius saourensis from a captive population

Aphanius saourensis is endemic to the Oued Saoura basin in the Algerian Sahara. Once it might have been widespread throughout the basin, but when it was last time found in 2004, only one remnant population (near Mazzer) had remained. When the species was described in 2006 (Blanco et al., 2006), it was already mentioned that “The presence of introduced North American Gambusia sp. poses a serious threat, with current densities of Gambusia to Aphanius being more than 100 to one. Excessive ground water withdrawal for agricultural purposes, the drying of wetlands, and water pollution are, along with the introduced Gambusia, the major threats to the survival of this species. Its survival is unlikely in the wild, but a small captive breeding program is underway“. In 2013, the German Killifish Association (DKG) in collaboration with Jörg Freyhof (IUCN FFSG chair the European Region) funded a small project to support Mahmoud Bacha and Chabane Benamirouche from Algeria to search again for the species at its type locality and other waterbodies in the Oued Saoura. Mahmoud and his team spent five days in the area and checked the type locality and all adjacent water bodies but with depressing results only. Beside Gambusia holbrooki, only alien tilapia (Oreochromis niloticus) could be found. This is the third extinct freshwater fish species in the Maghreb. There was no trace of the Aphanius. Naturally, a negative record is difficult to make and there might be still the chance to re-discover the species in the wild. But based on the actual results, we should treat the captive stock, which exist in some European countries, in a way as if the wild population would be gone. The next question is, if the Aphanius could be re-introduced to the wild? As its extinction in the wild was caused by the impact of alien species, these must be removed from the future re-introduction site. This might be a real challenge, even in a dry area as the Algerian Sahara. It should be noted, that there are at least four more North African species which might be at the very brink of extinction: Aphanius apodus, Barbus reinii, Ptercapoeta maroccana and Salaria atlantica. These have not been assessed yet or have been assessed as Data Deficient, as no data were available from the poorly known area. More detailed fieldwork is urgently needed to search for them, not to discover in some years, that they are also just gone extinct.

Literature cited.
Blanco, J. L., Hrbek, T. & Doadrio, I. 2006. A new species of the genus Aphanius (Nardo, 1832) (Actinopterygii, Cyprinodontidae) from Algeria. Zootaxa, 1158: 39 – 53.

García, N., Cuttelod, A. & Abdul Malak, D. 2010. The status and distribution of freshwater biodiversity in Northern Africa. Gland, Switzerland, Cambridge, UK, and Malaga, Spain : IUCN, xiii+141pp.