Next STEM lecture features a fish story

There are fewer fish swimming in the American River and that’s a major concern for California and the topic of the next Science, Technology, Engineering and Mathematics (STEM) lecture, 7 p.m. Tuesday, Nov. 18 in the University Union’s Redwood Room.

The lecture will be given by Sacramento State professor and hydrogeologist Tim Horner. Horner has watched the dramatic decline in salmon and steelhead species and has focused his attention on their habitat.

“Since 2002, adult salmon and steelhead populations on the American River have decreased to 2 percent of their former level,” says Horner. “That's a huge decline, and we need to get a handle on the reasons."

Horner said the declining fish populations have been linked to any number of conditions, including global warming, ocean conditions, commercial or recreational fishing, delta water demands, sediment input, water diversions, water quality, dams and water releases. He has a few ideas of his own, and will talk about possible stresses to American River fish.

Horner and his students have worked on local stream restoration projects and have collected information about the health and habitat suitability for steelhead and salmon on the American River.

“We have helped to characterize conditions that are ideal for salmon and steelhead spawning and will use them as a target to guide habitat restoration projects,” says Horner.

Horner specializes in groundwater/surface water interaction, and teaches undergraduate and graduate classes in sedimentology, field geology and hydrogeology. He joined the Geology Department in 1993.