|Document Type:||Contract Report|
|Title:||Smolt passage behavior and flow-net relationships in the forebay of John Day Dam (Part 2)|
|Author/Editor:||Albert E. Giorgi, Lowell C. Stuehrenberg|
|Publisher:||National Marine Fisheries Service|
|Contracting Agency:||Bonneville Power Administration. Portland, Oregon|
During 1984, our research program in the forebay of John Day Dam had three separate but complementary phases: monitoring current patterns, defining fish distribution with purse-seine sampling, and assessing the value of a new application of radio tag methodology designed to examine passage behavior of juvenile salmonids.
Preliminary results from purse-seining operations in 1984 support observations made in 1983, i.e., discharge from the John Day River and the turbid plume it forms in the forebay may have a pronounced effect on the distribution of smolts as they approach the dam. The implication of these data is that the plume may be shunting salmon toward the Washington (spill) side of the river, where they would be more susceptible to spill passage. These findings will be subsequently analyzed in conjunction with 1983 data and therefore must be considered preliminary at this time. Data describing the current patterns during 1983 and 1984 will be incorporated into an overall analysis of the relations of current patterns and John Day River discharge to fish migration patterns.
A new research application of radio-tag methodology was successfully executed. From 57 to 100% (mean 79%) of the individuals in various groups of smolts fitted with radio tags and released 6 km upstream from John Day Dam successfully migrated to and were detected at the dam. Furthermore, it was possible to positively identify the specific passage route (spillway, powerhouse, fishladder, or navigation lock) used by each uniquely coded individual.