Endangered Razorback suckers and Colorado pikeminnows in the Colorado River, USA, are suffering from a lack of water flow.
Due to a water shortage for the fifth year in a row, officials have had to suspend high flows use to enhance the habitat of the fishes, says a report in The Daily Sentinel. The extra water is needed to flush away sediment and aquatic vegetation, but despite heavy rains in April, a lack of snow earlier in the year has lead to a water crisis.
The Razorback sucker, Xyrauchen texanus, is listed on the IUCN Red List as Endangered, while the Colorado pikeminnow, Ptychocheilus lucius, is listed as Vulnerable.
Hydrologist George Smith of the US Fish and Wildlife Service told The Daily Sentinel: "Nobody wants to part with any water in a year like this," Smith said. "Most of the reservoirs are not going to fill this year, and there's no extra water in the system.
"I think everybody probably knew this was coming."
Smith added that the fish had managed to survive for five years without the extra flow, so hoped that the effects wouldn't be long lasting.
Both the Razorback sucker and the Colorado pikeminnow have a very low population doubling time of just 14 years, which does not make them very resilient to problems which affect their reproduction.