The deaths within days of 11 sturgeon, a species unchanged for thousands of years, have puzzled scientists
When the first spindly, armour-clad carcass was spotted in the fast-flowing Nechako River in early September, Nikolaus Gantner and two colleagues scrambled out on a jet boat, braving strong currents to investigate the grim discovery.
Days later, the remains of 10 others were spotted floating along a 100km stretch of the river in western Canada.