Adult Arctic Grayling were caught and tagged in the Kuparuk River. A second fishing campaign occurred later in the summer, and any fish that was recaptured was remeasured to determine growth. Phosphorus addition has occurred since 1983; station sites are relative distance from the original 1983 phosphorus dripper. Stations include sites in a reference, recovery, and fertilized reach. Reaches were defined based on the location of phosphorous addition (see methods). Arctic Grayling were caught early in the field season, tagged, and recaptured late in the field season.
Since 1983, the Streams Project at the Toolik Field Station has monitored physical, chemical, and biological parameters in a 5-km, fourth-order reach of the Kuparuk River near its intersection with the Dalton Highway and the Trans-Alaska Pipeline. In 1989, similar studies were begun on a 3.5-km, third-order reach of a second stream, Oksrukuyik Creek. Fish were collected on each river. Station locations, representing kilomter values certain distances from original phosphorus dripper (see method) were noted.