Pink salmon migrate in huge numbers up the Indian River in Sitka National Historical Park every August. A recent paper written by Chris Sergeant with the National Park Service’s Southeast Alaska Network and three co-authors found that the combination of low river flow and abundant salmon can often cause low dissolved oxygen events that lead to fish mortality. River water diversion for human use and stray hatchery salmon – those fish that return to rivers instead of their hatchery of origin – have the potential to increase the magnitude and frequency of these low dissolved oxygen events through Southeast Alaska. The research is freely available online at Ecosphere.