How much protein has been removed from the oceans by humans in the last 50 years?Paul
This question is a real stumper. First, it’s important to note that an exact number is impossible to calculate because we don’t know the exact composition of the global seafood catch. While the UN’s Food and Agriculture Organisation makes official attempts to log all the fish caught in a given year, those numbers don’t account for unreported fishing and bycatch that is discarded back to sea.
Alternatively, the Sea Around Us initiative provides an estimate of all the fish caught yearly, including the reported catch plus an estimate of illegal fishing and bycatch, among others. That makes it a better resource to help us calculate this kind of number, providing global catch estimates for the years 1950 to 2018.
For the purpose of answering this question (and to keep it simple), we’ll focus only on wild-caught fish, and not include aquaculture (fish farming). On fish farms, producers are artificially rearing their stocks, so it can confuse the picture of actual ocean ecosystem turnover.