How "full" were the oceans before commercial farming became mainstream?

Hello All,

Wanted to ask, but I imagine the seas were multiple of every fish and other sealife imaginable, before commercial fishing came to be mainstream. So even say, 100 years ago I imagine it was a night and day difference.

Massive pods of whales, dolphins etc.

Any articles or stories of how blooming with life the oceans were say, before the 20th century?

Mistyped title, should have been fishing instead of farming.