Nearshore Habitat Use by Juvenile Chinook Salmon in Lentic ...

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Depth (m) . 0.6 0.5 0.4 0.3 2003 2004 0.2 Feb Mar Apr May Jun 37653 37683 37713 37743 37773 FIGURE 35.—Mean water column depth (m) where juvenile Chinook salmon were located in the index reach of Johns Creek, 2003 and 2004. Figure only includes dates when at least 10 Chinook salmon were observed. A total of only six Chinook salmon were collected in riffles (only sampled in 2004). They were collected in February and early March and were located in small pocket water behind boulders. Juvenile Chinook salmon density was highest in glides in February and early March. In both 2003 and 2004, the density in the beginning of March was about twice as high in glides than scour pools. The density in glides declined dramatically in late March and after the beginning of April, few Chinook salmon were present in glides and those that were present were almost always under overhanging vegetation. In April and May, the density in scour pools was 3 to 65 times higher than in glides. Juvenile Chinook salmon were present in scour pools throughout the study period (Figure 36). In February, they were located in shallow areas of the pool such as the edges and tailouts. After February, they were found in deeper water and by the end of March they were usually in the deepest part of the pool (Figures 37 and 38). Similarly to scour pools, Chinook salmon were present in the convergence pool throughout the study period, albeit at a much lower density (Figure 39). Chinook salmon in the convergence pool were usually close to the edge and associated with shoreline vegetation. One notable exception was in February, 2004 when most Chinook salmon in the convergence pool were located under the footpath bridge. Large numbers of juvenile Chinook salmon were also observed under the bridge in 2002. The March and April abundance of Chinook salmon in the convergence pool was higher in 2004 than 2003, even though the abundance in all habitats combined was higher in 2003. To compare the use of the convergence pool to the rest of the index reach, we calculated the number per stream length because the convergence pool is wide and Chinook salmon do not appear to use the large area in the middle of the stream channel. The number of Chinook salmon per stream length was 3 to 26 times lower in the convergence pool than the rest of the stream in 2003; however, in 2004 it was only 2 to 7 times lower (Figure 36). The water 59
column depth used by Chinook salmon in the convergence pool was similar to the average depth available. The deep areas (> 0.9 m deep) of the convergence pool did not appear to be used extensively by Chinook salmon. Instead these areas were often inhabited by large trout or largemouth bass (Micropterus salmoides), which may have influenced the distribution of juvenile Chinook salmon. 2.5 2003 Chinook / m 2 2 1.5 1 0.5 Scour pools Glides Convergence pool 0 2/1 Feb 3/3 Mar 4/2 Apr 5/2 May 6/1 Jun 7/1 Chinook / m 2 1.4 1.2 1 0.8 0.6 0.4 0.2 0 2004 Scour pools Glides Convergence pool 2/1 Feb 3/2 Mar 4/1 Apr 5/1 May 5/31 Jun 6/30 FIGURE 36.—Density (number /m 2 ) of juvenile Chinook salmon in three habitat types in the lower 260 m of Johns Creek, 2003 and 2004. Density in riffles is not shown because few fish were observed. Note different scales between years. 60
Page 1 and 2:
U.S. Fish and IU.S. Wildlife FishSe
Page 3 and 4:
SUMMARY In 2003 and 2004, we contin
Page 5 and 6:
An overhanging vegetation/small woo
Page 7 and 8:
Table of Contents Page SUMMARY ....
Page 9 and 10:
List of Figures Figure Page FIGURE
Page 11 and 12:
FIGURE 37.—Water column depth (m)
Page 13 and 14:
The major tributary to Lake Washing
Page 15 and 16:
Fry emerge from their redds from Ja
Page 17 and 18:
FIGURE 2.—Location of index sites
Page 19 and 20: most dates (Figure 4). Unlike 2002,
Page 21 and 22: Chinook/m 2 1 0.8 0.6 0.4 0.2 0 Wes
Page 23 and 24: 0.3 Mercer Island Chinook/m 2 0.2 0
Page 25 and 26: particularly valuable. Shoreline im
Page 27 and 28: FIGURE 8.—Map of south Lake Washi
Page 29 and 30: FIGURE 10—Map of south Lake Washi
Page 31 and 32: # of marked Chinook 40 30 20 10 0 A
Page 33 and 34: CHAPTER 3. RESTORATION SITES Introd
Page 35 and 36: Beer Sheva Park.—At Beer Sheva Pa
Page 37 and 38: Results Seward Park, 2003.—In 200
Page 39 and 40: 4 3.5 Chinook/100 m 3 2.5 2 1.5 1 0
Page 41 and 42: Martha Washington Park, 2003.—In
Page 43 and 44: 120 Chinook/100 m 100 80 60 40 20 s
Page 45 and 46: snorkeling and scuba diving were co
Page 47 and 48: Water column depth (m) . 0.80 0.60
Page 49 and 50: CHAPTER 5. FEEDING AT TRIBUTARY MOU
Page 51 and 52: FIGURE 28.—Location of four south
Page 53 and 54: FIGURE 29.—Photos of sites used t
Page 55 and 56: sampling. At night, Chinook salmon
Page 57 and 58: TABLE 5.—Diet overlap indices (C)
Page 59 and 60: TABLE 7.—Diet overlap indices (C)
Page 61 and 62: TABLE 10.—Diet composition of juv
Page 63 and 64: The lack of a large difference betw
Page 65 and 66: CHAPTER 6. USE OF NONNATAL TRIBUTAR
Page 67 and 68: shallow to snorkel were surveyed th
Page 69: Number of Chinook ff 700 600 500 40
Page 73 and 74: Chinook / m . 5 4 3 2 1 2003 - upst
Page 75 and 76: TABLE 13.—Diet overlap index (C)
Page 77 and 78: (P. Castle, WDFW, unpublished data)
Page 79 and 80: FIGURE 41.—Placement of Scotch br
Page 81 and 82: FIGURE 43.—Photo of a group of ju
Page 83 and 84: CHAPTER 8. LAKE QUINAULT SURVEYS In
Page 85 and 86: FIGURE 45.—Photos of large woody
Page 87 and 88: Similar to April surveys, the nears
Page 89 and 90: Chinook / 100m . 500 400 300 200 10
Page 91 and 92: Tabor and Wurtsbaugh (1991) conclud
Page 93 and 94: FIGURE 48.—Location of south Lake
Page 95 and 96: FIGURE 49.—Conducting visual obse
Page 97 and 98: FIGURE 52.—Photo of a group of ju
Page 99 and 100: ACKNOWLEDGMENTS We wish to thank He
Page 101 and 102: workshop, Shoreline, Washington, No
Page 103 and 104: Paron, D.G., and E. Nelson. 2001. S
Page 105 and 106: Werner, E.E., and D.J. Hall. 1988.
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Nearshore Habitat Use by Juvenile Chinook Salmon in Lentic ...

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