Why did salmon farming start?

Salmon farming got started because there was not enough fish for everyone. Everyone can get salmon even if it is not the salmon season if you farm salmon. The population is growing so we have to find more food. By farming salmon, there will be more seafood supply and half of the world's seafood is farmed. There is fresh salmon in every season, and fresh salmon is healthy. Commercial fishing can only harvest salmon at the right time of the year.