Initialisation Appendix Egg seeding example

This appendix provides an example of egg seeding initialisation. In OSMOSE 4.4, seeding is implemented through the reproduction process of the OSMOSE core simulator. In practice, it can be used either to establish the first reproducing population when mature individuals are initially absent, or as a safeguard against irreversible collapse by maintaining a minimal reproductive source.

A typical biomass-based configuration for oviparous species is:

population.seeding.year.max = 50

population.seeding.biomass.sp0 = 6420
population.seeding.biomass.sp1 = 8068
population.seeding.biomass.sp2 = 6916
population.seeding.biomass.sp3 = 9940
population.seeding.biomass.sp4 = 3000
population.seeding.biomass.sp5 = 37868
population.seeding.biomass.sp6 = 3316
population.seeding.biomass.sp7 = 28544
population.seeding.biomass.sp8 = 10720
population.seeding.biomass.sp9 = 186040

In this example, seeding is available for fifty years. For each focal species, the configured seeding biomass is used only if the species produces no eggs from mature schools and the simulation is still within the seeding period.

For viviparous species, the same logic applies, but the seeding quantity is specified as abundance instead of biomass:

population.seeding.year.max = 10
population.seeding.abundance.sp3 = 2.5e6

As a rule of thumb, a very low seeding value can be used as a collapse safeguard, whereas a larger seeding value can be used to help establish the first reproducing population when the model starts without mature individuals.