Table 10.
Observed number of CWTs from 2017 Canadian fishery sampling, estimated 2017 catch in Canadian fisheries of hatchery‐origin adult coho salmon via CWTs, ER (%) via CWTs of adult coho salmon in Canadian fisheries, estimated 2017 escapement of hatchery‐origin adult coho salmon, observed assignments via PBT from 2017 fishery sampling, estimated catch via PBT‐GSI, ER of clipped adult coho salmon, total adult 2017 escapement, adipose fin clip rate observed in escapement, and clipped hatchery component of adult escapement for selected coho salmon populations. N/A is not applicable as CWTs were not applied to the population
| Population | Coded‐wire tags | PBT‐GSI | Adipose clips | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Catch | Escapement | Catch | Escapement | |||||||
| Obs. CWTs (adults) | Estimated catch (adults) | ER | Hatchery‐origin | Obs. PBT | Estimated catch | ER | Total adults | Clip rate | Hatchery‐origin clipped | |
| Quinsam | 62 | 1,323 | 31 | 3,010 | 88 | 1,135 | 28 | 3,480 | 82.3[Link] | 2,864 |
| Puntledge | 3 | 142 | 10[Link] | 1,330 | 3 | 81 | 32 | 2,397 | 7.1[Link] | 170 |
| Big Qualicum | 40 | 1,365 | 22 | 4,834 | 71 | 1,679 | 22 | 6,933 | 84.9 | 5,886 |
| Robertson (swim‐ins)[Link] | 117 | 4,030 | 44 | 5,206 | 267 | 3,110 | 27 | 9,511 | 88.0 | 8,370 |
| Inch | 117 | 1,879 | 41 | 2,781 | 108 | 1,488 | 35 | 2,779 | 99.7 | 2,771 |
| Coldwater | 9 | 97 | 16 | 518 | 8 | 157 | 23 | 2,178 | 24.1 | 525 |
| Salmon | 4 | 51 | 10 | 453 | 5 | 87 | 16 | 676 | 65.4 | 442 |
| Nitinat (swim‐ins)[Link] | N/A | 23 | 723 | 33[Link] | 1,497 | 96.1 | 1,439 | |||
| Conuma | N/A | 10 | 399 | 20[Link] | 3,910 | 41.9 | 1,638 | |||
| Rosewall | N/A | 4 | 151 | 65[Link] | 80 | 100.0 | 80 | |||
| Goldstream | N/A | 7 | 746 | 96 | 99 | 33.3 | 33 | |||
| Tenderfoot | N/A | 41 | 852 | 55[Link] | 925 | 74.7 | 691 | |||
| Capilano | N/A | 135 | 3,089 | 21[Link] | 12,244 | 96.9 | 11,864 | |||
| Chilliwack (swim‐ins) | N/A | 253 | 5,507 | 28[Link] | 14,492 | 97.7 | 14,159 | |||
| Chehalis (swim‐ins) | N/A | 57 | 924 | 72[Link] | 587 | 61.5 | 361 | |||
CWT hatchery‐origin includes unclipped tagged which do not get counted in clipped hatchery‐origin for Quinsam River.
In 2014 broodyear, 12.8% of Puntledge fry release was clipped and tagged, and the remainder was released unclipped. In 2017 escapement sampling, a CWT loss rate of 31% was observed due to sampling for otoliths and CWTs from the same individual.
Total escapement to the Stamp River plus Robertson Creek was 21,175 adults. 9,511 adults is the hatchery return, which is all that was sampled.
Total escapement to the Nitinat River was 4,883 adults. Clip rate is from swim‐ins so total adults is just swim‐ins, same as Robertson Creek.
Minor components of the escapement were not enumerated; however, the exploitation rate can be considered reasonably accurate due to the very high percentage of total return that were enumerated in the hatchery swim‐in count at Nitinat River, Capilano River, and Chilliwack River.
Significant components of the escapement were not enumerated; consequently, exploitation rate was overestimated by a large but unknown percentage.