RCN Marine Disease Modeling and Transmission Workshop

Example solution for single species single population model with recruitment (abalone2)

There are two recruitment possibilities: recruitment from the local population or recruits coming from a remote (undiseased) population.

Both of these cases are in the same matlab model code. Different parameter choices activate one or the other recruitment processes. It is possible for both to be active at the same time, of course.

Local Recruitment

model parameters: local recruits PAR.ReproS 0.02 PAR.ReproI 0.01 PAR.Carry 100 PAR.Carry2 10 PAR.Repro2 0.01 PAR.Imm 0.0 PAR.Diff 0.0 PAR.IPinfect 0.003 PAR.Iinfect 0.001 PAR.Dinfect 0.0008 PAR.Imort 8.d-2 PAR.Bmort 0 PAR.DeadDecay 1.5 PAR.Irelease .015 PAR.Drelease 1.0 PAR.IPremove 0.001
As a diagnostic, the infection rate for the three different processes are calculated from the model solution. The lines represent the particle infection rate (solid line), the infected contact infection rate (dashed line) and the dead infected contact infection rate (dot-dashed line).
The immigration rate from remote population by either immigration (constant motion) or diffusion (concentration dependent). This case has no exchange activated.
The local and remote population recruitment rate. For this case, both susceptible and infected local animals can reproduce. The remote population simply grows to its carrying capacity, but does not participate in recruitment.

Recruitment by immigration

model parameters: local recruits PAR.ReproS 0.0 PAR.ReproI 0.0 PAR.Carry 100 PAR.Carry2 10 PAR.Repro2 0.01 PAR.Imm 0.001 PAR.Diff 0.001 PAR.IPinfect 0.003 PAR.Iinfect 0.001 PAR.Dinfect 0.0008 PAR.Imort 8.d-2 PAR.Bmort 0 PAR.DeadDecay 1.5 PAR.Irelease .015 PAR.Drelease 1.0 PAR.IPremove 0.001
As a diagnostic, the infection rate for the three different processes are calculated from the model solution. The lines represent the particle infection rate (solid line), the infected contact infection rate (dashed line) and the dead infected contact infection rate (dot-dashed line).
The immigration rate. As animals arrive from the remote population, they become infected. Clearly, the remote population is being drained of animals.
The local and remote population recruitment rate. For this case, there is no local reproduction. As the remote population declines due to exchange with the local population, the reproduction rate is declining.