Genesis 1:22 New English Translation

²²God blessed them^[a] and said, “Be fruitful and multiply and fill the water in the seas, and let the birds multiply on the earth.”^[b]

Genesis 1:22 tn While the translation “blessed” has been retained here for the sake of simplicity, it would be most helpful to paraphrase it as “God endowed them with fruitfulness” or something similar, for here it refers to God’s giving the animals the capacity to reproduce. The expression “blessed” needs clarification in its different contexts, for it is one of the unifying themes of the Book of Genesis. The divine blessing occurs after works of creation and is intended to continue that work—the word of blessing guarantees success. The word means “to enrich; to endow,” and the most visible evidence of that enrichment is productivity or fruitfulness. See C. Westermann, Blessing in the Bible and the Life of the Church (OBT).
Genesis 1:22 sn The instruction God gives to creation is properly a fuller expression of the statement just made (“God blessed them”), that he enriched them with the ability to reproduce. It is not saying that these were rational creatures who heard and obeyed the word; rather, it stresses that fruitfulness in the animal world is a result of the divine decree and not of some pagan cultic ritual for fruitfulness. The repeated emphasis of “be fruitful—multiply—fill” adds to this abundance God has given to life. The meaning is underscored by the similar sounds: בָּרָךְ (barakh) with בָּרָא (baraʾ), and פָּרָה (parah) with רָבָה (ravah).

New English Translation (NET)