Log Lunch with Sonya Auer, A gift from the grave: How salmon parents nourish their offspring even after death.

Professor Sonya Auer (right) and Professor Sarah Gardner (left)

Sonya Auer, Visiting Assistant Professor of Biology, studies the ways in which animals cope with change in their environment. She gave a Log Lunch this week about her work on salmon in the highlands of Scotland. She explained how dams pose a barrier to salmon migration and are linked to decrease in salmon population. Atlantic salmon impact the environments they move through, especially freshwater streams because of their role as nutrient transport vectors. Professor Auer explained that after spawning in their natal freshwater streams, many salmon die and their decomposing bodies release nutrients into the ecosystem that eventually benefit their young. Macroinvertebrates feed off of the decomposing bodies and fry, or baby salmon, eat these macroinvertebrates. With dams in place, there is a net export of nutrients from natal streams because spawning salmon cannot get to the streams to spawn and die. Professor Auer and her team conducted a multi-year nutrient manipulation experiment to figure out how nutrients from decomposing post-spawning parents impact 1) macroinvertebrate availability, and 2) juvenile salmon growth and biomass. She found that nutrient restoration had a significant and persistent effect on both macroinvertebrate abundance and biomass. Her results also showed that nutrient restoration had a significant effect on the mean biomass of juvenile salmon. Overall, she concluded that parental nutrient had a huge impact on the freshwater. Professor Auer’s investigation uncovered the potential role that nutrient restoration could have in salmon conservation.

By Cristina Mancilla ’20