The weekly wash-up (February 7th)

River and water news – February 7th, 2014

Pacific salmon inherit magnetic sense of direction  New research has shown salmon can detect and respond to the Earth’s magnetic field. The finding may help explain how the fish can navigate across thousands of miles of water to find their river of origin. In essence, fish possess a “map sense” determining where they are and which way to swim based on the magnetic fields they encounter. Experiments used fish that had never left the hatchery and thus we know that their responses were not learned or based on experience, but rather they were inherited.

Call to improve access to fluoridated drinking water  The National Rural Health Alliance (NRHA) is calling on the federal government to take action to improve access to fluoridated drinking water in rural and remote areas. The NRHA says fluoridation of drinking water is widely regarded as the most cost effective health promotion intervention available in a wealthy country such as Australia, because of its positive impact on dental health. In 2010-11 there were over 60,000 preventable hospitalisations related to dental conditions.

California is experiencing its worst drought in 500 years. Photo by S. Linke.

Some parts of California are always dry but towns and farmers are now experiencing their worst drought in 500 years. Photo by S. Linke.

California in grip of ‘worst drought in 500 years’   The crisis in California is unfolding in ways expected and unexpected. Without rain to scrub the air, pollution in the Los Angeles basin, which has declined during the past decade, has returned to dangerous levels. The impact has been particularly severe on farmers and ranchers with animals running out of feed and crops unplanted. In the worst scenario, drinking water would have to be brought by truck into parched communities and additional wells would have to be drilled to draw on groundwater.

Melbourne water supplies: Don’t flush successful conservation down the drain  Melburnians were the world’s best water-savers between 2000 and 2010. Water use per person was 40% less than the decade before. Without this water-saving effort, Melbourne’s drinking supplies would have run dry around June 2009. But last month water use peaked at 255 litres a person up from 146 in 2009-10. A recently released water strategy says, under a ”business as usual” scenario two additional desalination plants may be required, at a total cost of $6 billion. Water conservation has been contributing more than 200 billion litres of water a year to water supplies – more even than the total capacity of the desalination plant. It is too good to waste.

The Mexican Axolotl may be extinct in its native range.

The Mexican Axolotl may be extinct in its native range.

Mexico’s “water monster” axolotl may have disappeared   Mexico’s salamander-like axolotl may have disappeared from its only known natural habitat in Mexico City’s few remaining lakes.The axolotl is known as the “water monster” and the “Mexican walking fish,” and its only natural habitat is Lake Xochimilco, which is suffering from pollution and urban sprawl. A recent three-month attempt to net axolotls found not one of the creatures.