Rare pupfish population found

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Scientists have discovered a population of endangered Desert pupfish in man-made research ponds in Salton Sea, California.

It is unknown how the pupfish made their way into the ponds, but experts now hope that the population will be able to provide them with critical research opportunities that could shed more light on this scarce fish.

The ponds had been set up for research on the Salton Sea ecosystem and migratory birds; however, that primary purpose may now change following the discovery of this population.

Healthy populationIt is estimated that over 1000 Desert pupfish, Cyprinodon macularius, are now resident within the research ponds, which are run by the US Geological Survey (USGS), US Bureau of Reclamation, Imperial Irrigation District, and the California Water Resources Control Board.

A more detailed survey of the population, which has been branded as a "scientific windfall" by Dr Douglas Barnum, a scientist with the USGS Salton Sea Science Office, is expected to take place once the necessary permits have been obtained.

The Desert pupfish are a native to Salton Sea in California, as well as the Colarado river, Gila river, Arizona and northern Mexico, however it is a bit of a mystery how they managed to find their way into the research ponds.

Breeding activityDr Saiki, a fisheries biologist with the USGS Western Fisheries Research Centre's Dixon Duty Station, said that many of the pupfish seen "are juveniles, which suggests substantial breeding activity within the ponds."

This could suggest that the water found in the ponds is suited to Desert pupfish, however Dr Saiki did warn that the researchers would have to observe how many of these fish "survive to adulthood before the real value of this habitat can be understood."

Research opportunitiesThe Desert pupfish are well-known for being able to withstand extremes of temperatures " and are found in hot springs that can reach 45C. The fish are also able to tolerate salt, being found in water with a salinity of up to 20%. The water found in the research ponds themselves are actually a blend of freshwater from the Alamo River, and saltwater from Salton Sea.

The mix of the two water sources was being used to control the salinity in the ponds, which was part of the research being carried out for the restoration of the Salton Sea Ecosystem.

It is hoped that this population of the scarce Desert pupfish will allow for further research into their water requirements " including those of temperature and salinity, as well as dissolved oxygen levels.

They hope also to gain an insight into the fishes interactions with other fish, and the effects of predation on the population, in order to gain a greater understanding as to why these fish have become endangered.

Dr Barnum told the USGS that "now that pupfish have been observed in the research ponds, we will modify the original goals and objectives allowing for this critically important line of research."