What does Genesis 1:22 mean?
For the first time in Genesis, God gives a direct spoken blessing. Specifically, He blesses all the creatures of the seas and the birds. His blessing is about reproduction and fertility and comes in the form of a command to these creatures: Be fruitful and multiply. In other words, God both commands the birds and fish to multiply and blesses them with the ability to do so. In making this statement, Genesis is declaring that God is not only the creator of life; He is the one who enables life to reproduce itself. He alone is the giver of fertility, of new generations.That's important for us to hear on several levels. First, to worship any other god in hopes of being blessed with fertile crops or herds or human families is a waste of time. Only God grants that blessing.
Second, whatever our position on how and when God created, Genesis insists that He is the one who blesses all creatures with the ability to reproduce another generation of their kind. Reproduction doesn't happen without Him. For all of its beauty, the creation account of Genesis provides very few actual details. What's meant to be understood, however, is profound: God and God alone is responsible for the design and existence of life.
Finally, we see in this verse that reproduction is a blessing. God grants new life as a gift and to fulfill His own purposes.