Could 10 tiny fry save Devils Hole pupfish from extinction?

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Scientists at a new research facility in the US have managed to hatch eggs from the endangered Devils Hole pupfish, whose adult population fell to an all-time low of just 35 earlier this year.

These eggs were the first to be collected from the wild and hatched in a controlled environment. The team at Ash Meadows Fish Conservation Facility in Nevada is hoping that if the fry can be grown on successfully to adulthood it could be the start of a new captive breeding programme, which could save these fish from extinction.

The $4.5 million facility was opened earlier this year and is located less than a mile from Devil's Hole — the deep, isolated pool in which the entire population of Cyprinodon diabolis feeds and breeds in an area of approximately 20 square metres, meaning it has the most restricted range of any vertebrate.

Ash Meadows Fish Conservation Facility is managed for the U.S. Fish and Wildlife Service and includes a 100,000 gal aquarium designed to be an exact replica of Devil's Hole itself, including dark caverns that extend underground and have to be accessed through a hatch next to the building.

This aquarium ranges in depth from 45cm/18" to 6.6m/22' and it will be used for a captive breeding programme if the fry currently being reared manage to make it to maturity.

According to a report in the Las Vegas Review-Journal, of the eggs harvested, 14 hatched and all but four of the fry have now made it to the three-week-old stage. The aquariums in which the young fish are being grown on are very different to those you'd want in your tank at home. They replicate the extreme conditions in Devils Hole, where the water is a constant 33°C/93°F and carries very little oxygen. Everything is computer controlled with back-up systems and automated alerts in case of problems.

Since population surveys began, numbers of the inch-long Devils Hole pupfish have not exceeded 553 individuals. For reasons that are still unclear, the population began to decline in the mid 1990’s and it hit a record low in spring this year.

With such a tiny population, scientists working at the facility have to ensure eggs are only harvested during periods when research has shown that the resulting fry are unlikely to survive.

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