Psalm 107:38 New English Translation

³⁸He blessed^[a] them so that they became very numerous.
He would not allow their cattle to decrease in number.^[b]

Psalm 107:38 tn “Bless” here carries the nuance “endue with sexual potency, make fertile.” See Gen 1:28, where the statement “he blessed them” directly precedes the command “be fruitful and populate the earth” (see also 1:22). The verb “bless” carries this same nuance in Gen 17:16 (where God’s blessing of Sarai imparts to her the capacity to bear a child); 48:16 (where God’s blessing of Joseph’s sons is closely associated with their having numerous descendants); and Deut 7:13 (where God’s blessing is associated with fertility in general, including numerous descendants). See also Gen 49:25 (where Jacob uses the noun derivative in referring to “blessings of the breast and womb,” an obvious reference to fertility) and Gen 27:27 (where the verb is used of a field to which God has given the capacity to produce vegetation).
Psalm 107:38 tn The verbal form in this line appears to be an imperfect, which may be taken as customary (drawing attention to typical action in a past time frame) or as generalizing (in which case one should use the English present tense, understanding a move from narrative to present reality).

New English Translation (NET)