Coastal Cutthroat Trout as Sentinels of Lower Mainland Watershed ...

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12Vancouver Island. Large streams with >130 km 2 were predominantly inhabited bysteelhead trout while small streams with drainage areas
13accounted for much of the variability of cutthroat abundance in small coho-cutthroatstreams, using 119 sites from Bella Coola and south (r 2 = 0.55; Rosenfeld et al. 2000).Anadromous Cutthroat Only ReachesAnadromous + Resident Cutthroat ReachesResident Cutthroat Only Reaches700Cutthroat Trout Biomass g/100 sq m60050040030020010000 1 2 3 4 5 6 7 8Average Summer Wetted Width m9Figure 1. Juvenile cutthroat trout standing crops (total cutthroat biomass per 100 m 2 ) inRegion 2 stream reaches versus wetted summer stream width (adapted from Deleeuw andStuart 1982: widths averaged from 1-2, 2-3, 3-5, 5-8 and 8+ m).Biomass data for rearing coastal cutthroat trout were also plotted by DeLeeuw and Stuart(1982) against average percent stream gradient. This clearly showed that streams of zerogradient supported zero rearing cutthroat, and streams near 0 to 0.5 % gradient supportedfew cutthroat. Typically, zero gradient reaches are sloughs or ditches, particularly withinthe lower Fraser Valley. In striking contrast, higher gradients from 0.5 % to >7 %supported high biomasses per unit area (Figure 2). Of note, resident trout reachessupporting higher biomasses per unit area were within the 4-8 m range of summer wettedwidths with moderate gradients of 2 %, the latter likely associated with boulderysubstrates and lower competition with sympatric juvenile coho salmon.As for the lentic waters of sloughs, ponds and lakes, cutthroat use is related to postglacialaccess, and to availability of nursery streams as well as the quality (cover) andproductivity (food availability) of the main water body. Further, some sloughs andditches are frequently only migratory corridors. Velocities can be low, and summer tofall conditions (particularly water temperature and/or dissolved oxygen) can be unsuitablein summer (unless groundwater-fed). Conditions may improve in fall to spring (Slaneyand Northcote 2003). For example, although velocities and depths are suitable in somesections of Mountain Slough and lower McCallum Ditch near Agassiz, they are
Page 1 and 2: Coastal Cutthroat Trout as Sentinel
Page 3 and 4: 3Sea-run cutthroat caught and relea
Page 5 and 6: 5EXECUTIVE SUMMARYA provincial stra
Page 7: 74. Cutthroat Nursery Habitat Resto
Page 10 and 11: 10Cutthroat trout are prized by man
Page 14 and 15: 14excessively warm and too low in d
Page 16 and 17: 16prefer pools in allopatric condit
Page 18 and 19: 18that are warmer and more producti
Page 20 and 21: 20Comparative benefits to densities
Page 22 and 23: 222, 23 % saltwater age 3 and 15 %
Page 24 and 25: 24are sexually immature (Leider 199
Page 26 and 27: 26management concerns are related t
Page 28 and 29: 28practices. Life-history profiling
Page 30 and 31: 30available in south coastal Britis
Page 32 and 33: 32Cutthroat smolt survivals are abo
Page 34 and 35: 34unproductive or oligotrophic stre
Page 36 and 37: 36were only small variable numbers
Page 38 and 39: 38Populations of juvenile cutthroat
Page 40 and 41: 40Unlike flood boxes with sluice ty
Page 42 and 43: 42weight/m 2 /yr (Wipfli and Gregov
Page 44 and 45: 44juvenile fish and non-target spec
Page 46 and 47: 46Figure 12. Trend in sea-run cutth
Page 48 and 49: 48at Hood Canal in Puget Sound (Big
Page 50 and 51: 50years owing to operational constr
Page 52 and 53: 5249 adult cutthroat were counted (
Page 54 and 55: 54Table 4. Areas of anadromous and
Page 56 and 57: 56population estimation and samplin
Page 58 and 59: 58Clayburn Creek, Draper Creek, Win
Page 60 and 61: 60females in 2000; hatchery females
Page 62 and 63:
625.2.4. Cutthroat Stream Stock Man
Page 64 and 65:
64Table 7. Cutthroat lake (stream)
Page 66 and 67:
66because piscivorous Taylor Lake c
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68and- Angler use was largely at th
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70spawners. This suggests that prot
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72• Public education initiative t
Page 74 and 75:
74Management Strategy 3: Recovery o
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76successful (Ptolemy 1997), and fu
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78It is widely assumed that most ad
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80annual frequency of repeat spawne
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82• Refinement of the minimum siz
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848. ReferencesAndrusak, H. and T.G
Page 86 and 87:
86Clark, B.J. 1988. The status of c
Page 88 and 89:
88Glova, G. L.1987. Comparison of a
Page 90 and 91:
90Knight, R. and J. Teskey. 1992. H
Page 92 and 93:
92eastern Fraser Valley. Prepared f
Page 94 and 95:
94Thomson, A.R. and Associates. 200
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969. GlossaryIt should be noted tha
Page 98 and 99:
98large woody debris (LWD): Entire
Page 100 and 101:
100Appendix 1. Known coastal cutthr
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102CHEAMSLOUGHCHEEKYERIVERCHEHALISR
Page 104:
104CRANBY LAKE LAKE ERROCK SAKINAW
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Coastal Cutthroat Trout as Sentinels of Lower Mainland Watershed ...

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