Genesis 1:20-23 - “ 20 And God said, “Let the water teem with living creatures, and let birds fly above the earth across the expanse of the sky.” 21 So God created the great creatures of the sea and every living and moving thing with which the water teems, according to their kinds, and every winged bird according to its kind. And God saw that it was good. 22 God blessed them and said, “Be fruitful and increase in number and fill the water in the seas, and let the birds increase on the earth.” 23 And there was evening, and there was morning—the fifth day.

Introduction
God's command for the proliferation of sealife and birds followed the appearance of the sun, moon, and stars. Whales are included as sealife and also resulted from God's command on Day 5. The problem is that whales appear to descend from land mammals, which appear to have been created on Day 6.
Consider that the key for seeded plants is that God's command was for their Evolution, and seeded plants are at the end of the Evolutionary chain (for plants). Rather than contradicting Evolution, scripture appears to prescribe it. Day 5 is similar...
20 And God said, “Let the water teem with living creatures, and let birds fly above the earth across the expanse of the sky.”
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22 God blessed them and said, “Be fruitful and increase in number and fill the water in the seas, and let the birds increase on the earth.”
"Let the water teem" (v. 20)
It is easy to read this command and think it was uttered when the seas were empty. However, this command refers merely to when the water was not teeming with sealife. There could have been some sealife already, though not much.
"Let birds fly... across the expanse of the sky" (v. 20)
Like sealife, this was uttered when birds were not filling the sky. There could have been some birds already, just not much.
The Key is God's Blessing (v. 22)
God's command in was to Jesus, His master craftsman: "Let the waters teem", "Let the birds fly across the sky". He then blessed the sealife and birds that already existed with a command to flourish. Catch that? The blessing came before they flourished.
Created "according to their kinds" (v. 21)
Most intereprete this phrase to mean that life was created to reproduce. However, scripture does not say that. Glenn Morton wrote, in "Why I Believe Genesis is Historically Accurate"...
Look at the object of this sentence and the modifying phrase, “Creatures… according to their kind.” God created creatures according to their kind. They were not commanded to reproduce according to their kind. Once again, a very different situation.
I misread this verse for years, because I did not believe that God created animals through Evolution. But, what is Evolution in the hands of God, if not the creation of creatures from creatures of the same kind?
Day 5: A Prescription for Evolution
On Day 5, God took the existing sealife and birds, and told Jesus to let them flourish. He then added a blessing for good measure. The domino was tipped, and based on the kinds of sealife and birds already in existence, other kinds evolved. Eventually, some evolved into land animals (spoiler: these aren't the land mammals from Day 6), and some of those evolved into whales... the creation of creatures from other creatures, according to their kind. But God did not make it happen; He "let" it happen.
Read about the KT Impact, and the conditions used by God on Day 5
Read about fish and bird Evolution
Read about whale Evolution, and why Day 5 does not overlap Day 6
Psalm 104:24-30
24 How many are your works, O LORD! In wisdom you made them all; the earth is full of your creatures.
25 There is the sea, vast and spacious, teeming with creatures beyond number— living things both large and small.
26 There the ships go to and fro, and the leviathan, which you formed to frolic there.
27 These all look to you to give them their food at the proper time.
28 When you give it to them, they gather it up; when you open your hand, they are satisfied with good things.
29 When you hide your face, they are terrified; when you take away their breath, they die and return to the dust.
30 When you send your Spirit, they are created, and you renew the face of the earth.
With Day 5 over, Jesus rode his chariot-cloud (the Holy Spirit) into the sunset, and into the sunrise of Day 6.