One more factor is weighing on the delta smelt, which I didn’t address in my story today: Pollution from agriculture.
Agricultural runoff has commonly been cited as having a serious effect on the smelt’s population. But Bill Bennett, the University of California, Davis research ecologist I spoke with, said toxic runoff doesn’t play as significant a role as has been thought. It’s a persistent but minor problem, he said.
Forensic analyses of the smelt have shown that 10 percent or less had encountered contamination from runoff. The effects are “sub-lethal,” Bennett said.
“It’s the equivalent of what someone’s liver would look like after a few nights of binging,” Bennett said. “But not a lifetime at the pub.”