Table 2.
Diet variables
|
Fish responses
|
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Diet composition % | Prey energy density (J g−1 w.w.)a | Prey Hg ± SE(ng g−1)b | Fish Hg (mg kg−1 w.w.)c | Hg uptake (mg)c | Specific consumption rate (J g−1 d−1)c | Specific growth rate (J g−1 d−1)c | Specific respiration rate (%)(J g−1 d−1)c |
Benthic diet | |||||||
Libellulids (48) | 4284 | 134 ± 31 | |||||
Gastropods (22) | 1807 | 205 ± 70 | |||||
Chironomids (19) | 2756 | 115 ± 14 | |||||
Coenagrionids (7) | 3365 | 188 ± 41 | |||||
Amphipods (4) | 3924 | 88 ± 19 | |||||
MEAN (Min Hg, Max Hg) | 3370 | 148 (111, 184) | 0.14 (0.11, 0.17) | 0.02 (0.01, 0.03) | 202 | 63 | 62 |
Cladoceran-dominated pelagic diet | |||||||
Cladocerans (75) | 2202 | 380 ± 61 | |||||
Copepods (25) | 2310 | 152 ± 25 | |||||
MEAN (Min Hg, Max Hg) | 2229 | 323 (271, 375) | 0.40 (0.33, 0.46) | 0.05 (0.04, 0.06) | 134 | 21 | 61 |
Copepod-dominated pelagic diet | |||||||
Cladocerans (25) | 2202 | 380 ± 61 | |||||
Copepods (75) | 2310 | 152 ± 25 | |||||
MEAN (Min Hg, Max Hg) | 2283 | 209 (175, 243) | 0.25 (0.21, 0.29) | 0.03 (0.03, 0.04) | 137 | 23 | 61 |
Mixed diet | |||||||
Benthic Prey (50) | |||||||
Libellulids (24) | 4284 | 134 ± 31 | |||||
Gastropods (11) | 1807 | 205 ± 70 | |||||
Chironomids (9.5) | 2756 | 115 ± 14 | |||||
Coenagrionids (3.5) | 3365 | 188 ± 41 | |||||
Amphipods (2) | 3924 | 88 ± 19 | |||||
Pelagic Prey (50) | |||||||
Cladocerans (37.5) | 2202 | 380 ± 61 | |||||
Copepods (12.5) | 2310 | 152 ± 25 | |||||
MEAN (Min Hg, Max Hg) | 2800 | 235 (191, 280) | 0.25 (0.22, 0.28) | 0.04 (0.03, 0.04) | 168 | 42 | 61 |
Prey energy density values from (Cummins and Wuycheck, 1971) and converted using dry weight: wet mass ratios from (Dumont et al., 1975) (Dumont et al., 1975) for zooplankton, (McPeek et al., 2001) (McPeek et al., 2001) for coenagrionids and assumed to be 0.2 for libellulids (Cummins and Wuycheck, 1971) (Cummins and Wuycheck, 1971).
Prey Hg values are from Table 1. See Methods for calculations of cladoceran and copepod values.
At 3.3 g wet weight.