FISHERY BULLETIN: VOL. 87. NO. 4, 1989 



varied seasonally. In general, fish caught in 

 April and May (all wild fish) occurred to a 

 greater extent in shoreline areas where currents 

 were reduced than fish caught in June (—90% 

 hatchery fish). Nearly three times as many 0- 

 age salmon were collected ft'om the two mid- 

 stream stations (barges 2 and 3) in June than in 

 April and May (Table 3). Analysis of the number 

 of fish caught showed a highly significant inter- 

 action (P < 0.0001) between the April/May and 

 June groups and capture location (barge or 

 depth). 



Late-Summer Outmigrants 



Low numbers of juvenile fall and summer 

 Chinook salmon occurred at Hanford during late 

 summer (July to September). We captured most 

 of these fish (21 of 26) in the midchannel station 



(barge 3), and 68% of them were collected from 

 the bottom sets. CPUE at barge 3 was 2.2 

 fish/100 h of sampling (all depths combined). This 

 corresponded to only 1.6 fish/m'^ x 10'' of water 

 filtered through the nets. CPUE at barge 3 

 during the peak sampling interval (early August 

 1983) was 7.1 fish/100 h, or 4.7 fish/m'^" x 10*^ of 

 water filtered through the net. 



Distribution of Spring Chinook Salmon 

 Smolts 



Yearling-sized chinook salmon occurred 

 throughout the spring in 1984. Most fish origi- 

 nated from the estimated 4 million spring 

 chinook salmon released from upper Columbia 

 River hatcheries in late April. 



Catches of yearling chinook salmon were 

 gi'eatest at the midchannel station (73%, n = 



Table 3. — Estimates of proportional distribution (%) for wild versus 

 hatchery populations of 0-Age fall chinook salmon. Shoreline stations 

 were fished only at ~ 1 m depth. 



Q. 

 IB 



Q 



60 120 180 240 300 360 



Distance from Benton County Bank (m) 



Figure 7. — Cross-sectional distribution of 

 yeariing chinook salmon (h = 459) caught in 

 shoreline and barge fyke nets during spring 

 1984. Note: horizontal scale is reduced. 



782 



