Deme J maintained a population of 8402 until there was a shift 4093.9 generations ago that decreased its numbers to 7706, a figure that has remained the same since.
time_units: generations
demes:
  - name: J
    start_time: .inf
    epochs:
      - start_size: 8402
        end_time: 4093.9
      - start_size: 7706
        end_time: 0