5
Probability of survival through the egg and larval stages are low (99.9% dies)
The number of individuals that survives the critical first 5 months (0-group) corresponds with numbers that reach age 3 years.
Total numbers of 3 year olds define the year-class strength.
However; processes important for larval survival and growth may differ between ecosystems
We know that most of eggs and  larval cod dies. And we also know that the ones that survives the first 5 months of their life, are the ones that we fish 3 years later. There fore to understand fisheries recruitment we can have to understand the underlying properties that control growth and survival though the first 5 months. Still, these processes may rely n the ecosystem that we are interested in and can be varying widely between ecosystems.