Brooks Falls 30-minute-interval scan sampling, July 2002

Vaughn, Imes

During July 2002, interpretive rangers stationed at the Brooks Falls viewing platform were asked to count salmon, bears, and people at 30-minute intervals. The scan sampling methods used to record these counts were similar to those described by D.L. Boyd (1997. Brown bear Monitoring, 1996, 1997, Brooks Camp, Katmai National Park. Resource Management Technical Report NPS/KATM/97-001, Katmai National Park and Preserve, King Salmon, Alaska). As close to the hour and half hour as possible, the following information was noted: the number of single bears and family groups, the number of people on the falls platform, and a 1-minute tally of the number of fish that attempted to jump over the falls (see Attachtments 1 and 2 for data form and instructions). The possible hours of data collection were from 9:00am to 9:00pm; however, the actual hours during which data were recorded varied somewhat among sample days. Data were collected from June 30 to July 30 (with the exception of July 18, when either the data were not collected or the data form was misplaced). To provide visitors and staff with current information regarding bar and salmon activity at Brooks Falls, I periodically posted an update graph in the Brooks Camp visitor center the depicted daily average 1-minute counts of salmon jumping and daily maximum counts of independent bears at the falls (Attachment 3).