Table 1. Natural mortality rates estimated by life history invariant methods and estimates of the effort required to exceed the sustainable harvest associated with each mortality rate.
| # nights | # fishers | % families | ||||||
|---|---|---|---|---|---|---|---|---|
| Method | Formula 1 | M | F 2 | FMSY 3 | MSY (kg) 4 | required 5 | required 6 | participating 7 |
| Hoenignls from Then et al. [56] | 4.899 * tmax -0.916 | 0.37 | 0.06 | 0.32 | 330,869 | 22,058 | 220.6 | 14.6% |
| Paulynls-T from Then et al. [56] | 4.118 * K0.73 * Linf-0.33 | 0.27 | 0.15 | 0.24 | 255,285 | 17,019 | 170.2 | 11.3% |
| Gunderson [57] | 1.79 * GSI | 0.30 | 0.12 | 0.26 | 279,557 | 18,637 | 186.4 | 12.3% |
1 See S6 Fig for life history traits used in analysis.
2 F = Z–M, where Z is 0.42 from the length-converted catch curve analysis (S7 Fig).
3 F MSY = 0.87 * M, from Zhou et al. [31].
4 MSY = (1- exp(-F MSY )) * BIOMASS, where Hovsgol grayling biomass is 1,214,400 kg based on Ahrenstorff et al. [21].
5 Number of nights required to reach MSY assuming fishers use 50-m of optimal mesh gillnet each night (15 kg grayling night-1).
6 Number of fishers required to reach MSY assuming each fisher uses 50-m of optimal mesh gillnet 100 nights per year.
7 Percentage of families participating in the fishery assuming a resident population of 5,440 and average family size of 3.6 people per household (1,511 families; NSOM [19]).