"The presence of large sturgeon is just one indicator that the waterway is recovering from serious industrial pollution.
New York’s Hudson river, once known as America’s Rhine in a nod to the famous European waterway, played a pivotal role in bolstering American power at the cost of decades of foul pollution.
Last June, researchers were shocked to discover some startling evidence of the river’s belated recovery. Scientists searching for the endangered Atlantic sturgeon hauled a special sonar from the back of their boat, using sound waves to bounce down on to the riverbed and detect any creature swimming underneath. Incredibly, the outline of an enormous 14ft (4.3 metre) sturgeon appeared on the screen.
“I thought ‘this is a big one’ and when we got back I sent the image to some colleagues,” said John Madsen, a University of Delaware geologist who ran the research. “Typically we may see a fish as big as three metres, so to see something a metre longer than that is quite something. Everyone was surprised, they said: ‘wow you’ve got to be kidding me, that is crazy.’”"
Oliver Milman reports for the Guardian March 28, 2019.
