Free fish prove popular in Arizona

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Officials from Maricopa County Environmental Services in Arizona, USA have seen a surge in demand for the free Mosquito fish (Gambusia affinis) they offer to owners of pools, ponds and fountains in the area.

The Vector Control Division from the county has been distributing the hardy species to help deal with problem mosquito populations for the past 20 years, but has seen an upsurge in demand for the fish in the last two years due to residents' concern over the rise in cases of the Mosquito-borne West Nile Virus.

The virus causes fever and meningitis-like symptoms and can be fatal.

So far this year over 300 people have requested the fish, while the division itself employs 26 inspectors to deal with swimming pools left green through lack of maintenance at abandoned or empty properties, as well as those owned by residents no longer able to maintain their pools due to ill health or financial reasons.

After treating each pool with algaecide, they typically leave between 15 and 20 of the larvae-loving fish to deal with the problem parasites. Advice is also given to pool owners regarding the release of the fish into local waterways where the prolific Gambusia could compete with native fish species.

Gambusia affinis are native to the watershed of the Gulf of Mexico and are famed for their tolerance of a vast range of water conditions and are now thought to be the most widely distributed fish species in the world, largely due to often ill-advised introductions to control mosquitoes.

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