Shortly before state water officials announced today that most urban water providers will no longer be subject to mandatory conservation targets, three environmental groups pleaded with the same panel for emergency flows through the Delta to prevent extinction of the smelt. It’s normal for some smelt to die off this time of year as juveniles mature into adults, Jon Rosenfield, a conservation biologist with The Bay Institute, told the State Water Resources Control Board. But something must be done to help a larger share of those babies make it to adulthood this year, he said.