TABLE 2

Estimates of Ne and Ne/N for Marsh Creek chinook salmon based on three methods (Equations 1, 2, 3) using demographic data from Table 1

e
GenerationYearsEquation 1Equation 2Equation 3e/Na
Generation length 4 years
11958–1961137220579860.48
21962–19652939320024840.78
31966–19692640304327230.89
41970–19732615280822340.80
51974–19776629945660.57
61978–19811887051100.16
71982–19853494271570.37
81986–19896509147620.83
91990–19934305033210.64
Harmonic mean e(9) (9 generations)5849643760.39
Generation length 5 years
11959–19631970284915160.53
21964–19684349459839750.86
31969–19732879319825560.80
41974–197895314858240.55
51979–19832193451910.55
61984–198891911309900.88
71989–19935035833610.62
Harmonic mean e(7) (7 generations)7169926070.61

A generation is assumed to include either 4 or 5 years of spawners. Nbi/Ni is assumed to be 1 each year.

  • a e from Equation 3 divided by e = NT from Equation 2.