• **Migration**

The migration process is either leaving or entering the species from an island. Biogeography-based optimization also used a population of candidate solution for optimization similar to partial swarm optimization and another population-based search method [31]. Depiction of all candidate solutions is complete as a vector of actual statistics. Now, all real statistics is considered in the population as suitability index variable (SIV). SIV [32] is similar to the output power of generating components in load frequency control. Few best solutions are the same in the resultant iterations; the migration process arranges to avoid the best solutions from being changed. Emigration rate [33] and immigration rate [34] for habitat contain '*k'* species is express as:

$$
\lambda\_k = I \left( 1 - \frac{K}{\eta} \right) \tag{6}
$$

$$
\mu\_k = \frac{Ek}{\eta},
\tag{7}
$$

where *E* represents the emigration rates, *I* represents the maximum immigration rates, and η represents the maximum number of species, respectively.
