Just something to think about...
To my knowledge the only translations that render it "replenish" are modern revisions of the KJV. The NKJV, NASB, NIV and 1611 KJV (I believe - I'm not 100% certain on that last one) all render it "fill".
And God blesseth them, and God saith to them, `Be fruitful, and multiply, and fill the earth, and subdue it, and rule over fish of the sea, and over fowl of the heavens, and over every living thing that is creeping upon the earth.' Ge 1:28 Youngs literal translation