"I am seeing some serious impacts that I don't think have been fully appreciated," said Pearson, a registered professional biologist and leading authority on the small fish.

You might not be familiar with the Nooksack dace, but streamkeepers and environmentalists have been working since the 1990s to stop the freshwater fish from going extinct, even taking the federal government to court over its failure to protect it.
The sediment spill happened at a "vulnerable" time of year for the fish, said Pearson, when the dace have normally burrowed down between rocks and boulders to find a quiet spot to spend the winter.