What data are needed
and who will provide them?
¥Nt+1 = Nt+B-D+I-E
¥
¥ For PseudocalanusÉ
¥ N = population  Bucklin, Durbin
¥ B = birth rates  Runge
¥ D = mortality  Runge, Ohman
¥ I = immigration   Pringle, McGillicuddy
¥ E = emigration   Pringle, McGillicuddy