Nandita Kohli

This is a screen grab of the Nonindigenous Aquatic Species Database. This database is used to track the spread of invasive aquatic species across the United States landscape.

This is a map of the nets on the Upper Klamath Lake in Oregon. The Western Fisheries Research Center carefully monitors juvenile Sucker populations for signs of population recovery and to better understand where they habitate.

Lost River and Shortnose suckers are on the verge of extinction in Upper Klamath Lake. Age data indicate that almost all adult suckers remaining in the lake spawning populations were hatched in the early 1990s.

Since 2009, the WFRC has partnered with Real Time Research to study bird predation of suckers. Scientists scan large nesting sites of fish-eating (piscivorous) birds, looking for PIT tags from juvenile and adult suckers that have been eaten by the birds.

We pack up, leave shore, and head toward our first target—a set of trap nets--with tempered hopes of finding something exceedingly rare: evidence of surviving juvenile suckers. After hours on the lake and around 20 nets void of juvenile suckers, we steer the boat back towards the marshlands near our truck. 

Its early morning as we pass a green expanse of farmland and pull into a parking lot with a boat ramp sloping into the massive waters of Upper Klamath Lake. Paving machines drone next to us, widening the road winding along the lake shore.

This is a photo of the endangered Klamath Sucker in Upper Klamath Lake, OR. Through decades of research, scientists of the USGS Western Fisheries Research Center have determined that, over the last 30 years, something has prevented young suckers from reaching adulthood.

This is a photo of fieldwork on the pilot Chinook egg survival study occurring in the Sacramento River, California.

This is a photo of a Chinook salmon fry taken by U.S. Fish and Wildlife, Roger Tabor, a Fish Biologist at the Western Washington FWCO.

This is a photo of a cutthroat trout being measured. It will then be used in experiments to understand the sublethal effects of the toxic tire byproduct chemical, 6PPD-quinone.

Salmon life cycles from egg to spawning adults with text explaining each life phase. 

This is a fish lifecycle diagram with the redd (egg), alevin, fry, and adult stages shown.

In this image, scientists are exposing fish to the toxic chemical, 6PPD-quinone, to better understand the toxin's effects. This work is being done at the Western Fisheries Research Center wetlab. The science is then used to develop solutions to the toxin.

This is the lower Granite Lock and Dam. Lower Granite Lock and Dam was authorized by the River and Harbor Act of 1945. The project includes a dam, a navigation lock, powerhouse, a fish ladder and associated facilities. It provides hydropower, navigation, flood risk management, fish and wildlife habitat, recreation and incidental irrigation.

This is the chemical structure of 6PPD-quinone, a toxic byproduct of the tire additive, 6PPD, which is used to make vehicle tires strong and safe on the roads. This toxic byproduct gets into runoff and into streams. This causes mortality in certain salmonids.

This is an infographic showing different fish and their sensitivity to 6PPD-quinone, on a logarithmic scale.

This is the tire chemical 6PPD. 6PPD is a common rubber antiozonant found in vehicle tires. It is mobile within the rubber and slowly migrates to the surface via blooming. On the surface it forms a "scavenger-protective film" that reacts with the ozone more quickly than the ozone can react with the rubber.

This is a diagram of a cross section of a dam. This diagram is to show where gas bubble trauma could occur.