Re-introduction of the “Extinct in the Wild”Yarqon bleak, Israel

Summary

The Yarqon bleak (Acanthobrama telavivensis), a cyprinid endemic to Israel's coastal river system, was reduced to three isolated populations by 1999 and pushed to the brink of extinction by a severe drought that year, prompting Tel Aviv University to rapidly build a rescue breeding facility and capture roughly 150 surviving fish just before their remaining habitats dried out, achieved through emergency cooperation between the university and three government authorities with no formal feasibility study possible given the urgency. Within three years the lab had bred the 150 rescued fish into over 10,000, developing husbandry protocols for spawning substrate, water temperature and larval diet from scratch, since almost nothing was known about the species' biology beforehand. A first release of about 5,000 adults into the Yarqon River in 2003 survived but failed to reproduce, traced to a lack of suitable spawning substrate and juvenile shelter; an experimental pond engineered with gravel, stone and native plants then confirmed thousands of juveniles could be produced once proper habitat was recreated. Building on this, roughly 9,000 laboratory-born fish were released across 12 mostly engineered sites in 2006-2007, and surveys from 2007-2009 found juveniles thriving at most sites, with the species reproducing in the wild for two to three consecutive years and its population increasing significantly. Major difficulties included an almost total absence of prior scientific knowledge and inadequate funding, met largely through volunteer effort. The project rates itself Highly Successful, crediting captive breeding, dedicated research, public engagement and a government water guarantee for returning a species listed Extinct in the Wild back to nature.