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

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CHAPTER 1. INDEX SITES Introduction In 2003, we continued our surveys of index sites in south Lake Washington to determine the temporal and spatial distribution of juvenile Chinook salmon. Index sites were initially surveyed in 2002. Results indicated that, from January to June, juvenile Chinook salmon were concentrated in the two sites closest to the mouth of the Cedar River. Because of cooler water temperatures in 2002, movement to more northerly sites may have been delayed. We repeated surveys of most of the index sites in 2003 to examine the level of variability between years and to determine if cooler temperatures in 2002 reduced movements to more northerly locations. Index site surveys were continued in 2004 on a limited basis to provide additional information for the City of Mercer Island. The city is planning to remove some aging sewer pipes along the shore of northwest Mercer Island; however, little is known about the abundance of Chinook salmon at this location. Methods 2003 surveys.-- Twelve index sites were surveyed in 2002; however, in 2003 we reduced the number of sites to nine so a two-person crew could easily get all the sites surveyed in one night. Of the nine sites, four were on the west shoreline, four were on the east shoreline and one was on Mercer Island (Figure 2). Sites typically had sand and small gravel substrate and a gradual slope; nearshore habitat that juvenile Chinook salmon typically prefer. Many of the sites were public swimming beaches. Habitat conditions of each index site were measured in 2002 (Table 2). Index sites were surveyed once every two weeks from February 4 to July 7. At each site, we surveyed a 50- to 125-m transect depending on the amount of high quality habitat available (sandy beach with gradual slope). Two transects were surveyed at each site, 0.4- and 0.7- m depth contour. Surveys were all done at night. Snorkelers swam parallel to shore with an underwater flashlight, identifying and counting fish. Transects widths were standardized to 2.5 m (0.4- m depth) and 2 m (0.7- m depth). Snorkelers visually estimated the transect width and calibrated their estimation at the beginning of each survey night by viewing a pre-measured staff underwater. Fish densities (Chinook salmon/m 2 ) were calculated by dividing the number of Chinook salmon observed by the area surveyed for each site and transect. A regression was developed between Chinook salmon density and distance of each site from the mouth of the Cedar River. 5
FIGURE 2.—Location of index sites in south Lake Washington used to study the temporal and spatial distribution of juvenile Chinook salmon. In 2003 (January to July), we surveyed four sites each on the west and east shorelines and East Mercer site on Mercer Island. In 2004 (February to June), the north Mercer and northwest Mercer sites were surveyed as well as the East Mercer, Kennydale Beach, and Gene Coulon Beach sites. The Cedar River, the major spawning tributary for Chinook salmon in south Lake Washington, is also shown. 6
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: Fry emerge from their redds from Ja
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 and 70:
Number of Chinook ff 700 600 500 40
Page 71 and 72:
column depth used by Chinook salmon
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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)
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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
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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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