220 
Fishery Bulletin 113(2) 
Figure 3 
Examples of lamprey wounds observed on (A) American shad (Alosa sapidissima ), 
(B) Chinook salmon ( Oncorhynchus tshawytscha), (C) shiner perch ( Cymatogaster 
aggregata), and (D) Pacific herring ( Clupea pallasii) caught in the lower Columbia 
River estuary during 2008-2012. The western river lamprey ( Lampeira ayresii) in 
panel A was observed attached to the American shad. 
both species were found throughout the estuary (rkm 
5-53) (Fig. 1). 
The winter-early spring timing of the occurrence 
of Pacific lamprey adults observed in our analysis is 
earlier than the timing previously reported for adults 
in the Columbia River and other rivers, although lim- 
ited winter sampling makes comparisons problematic. 
In the Columbia River estuary, adult Pacific lamprey 
were observed during April-May by Dawley et al. 4 , but 
4 Dawley, E. M., R. Ledgerwood, and A. L. Jensen. 1985. 
Dawley et al. were not sampled during winter or early 
spring. Adults have been counted crossing Bonneville 
Dam (rkm 235) between early May and late Septem- 
ber, and the highest counts were recorded in July (Fish 
Passage Center [FPC] query page for dam counts of 
Beach and purse seine sampling of juvenile salmonids in the 
Columbia River estuary and ocean plume, 1977-1983: Vol- 
ume I: Procedures, sampling effort, and catch data. Final 
Report of Research funded by Bonneville Power Administra- 
tion. [Available from Northwest Fish. Sci. Cent., Natl. Mar. 
Fish. Serv., 2725 Montlake Blvd. E., Seattle, WA 98112-2097.] 
