The Puyallup Tribe of Indians recently released their summary report on juvenille salmon monitoring in the Puyallup River watershed. The tribe operates a smolt trap in the lower river which counts outgoing salmon. The report covers research between January 18 and August 10, 2008.
The most significant finding in the report is the high number of unmarked (assumed not to be of hatchery origin) chinook. From the report:
A total of 4,760 unmarked Chinook migrants were captured in the screw trap between January 31st and August 9th. Fifty-three percent (2,517) was actual catch and 47% (2,243) was expanded catch. This is the highest number of unmarked Chinook captured in the smolt trap since the beginning of trapping on the Puyallup River in 2000. This year the trap was installed about one month earlier to investigate the possibility of missed catch in previous years. Between January 31st and February 15th, 29 Chinook were captured, 0.61% of total catch.
In general, catch was fairly consistent from the first fish until the last fish except for three individual peaks: the first peak was the second largest (239) and occurred on March 3rd, the second peak was the largest peak and occurred on May 14th (365) and the last and smallest peak occurred on June 29th (148). All peaks coincided with increases in flow. Catch is not used to describe migration timing of Chinook; instead daily production estimates are used. Hourly expansion was used to estimate catch for the peaks occurring on May 14th and June 29th peaks. As discussed previously, catch on the days when the trap was not fishing might not reflect the actual catch had the trap been operating.