The human diet appears to have reached an important milestone, as worldwide fish farm production has surpassed beef production for the first time in the modern era.

That's according to figures from the United Nations and U.S. Department of Agriculture.

It's another sign of the fish farming boom, taking place across the globe, which has also seen more and more universities dedicate programs to aquaculture.

The UN’s Food and Agriculture Organization estimates that fish farm production has grown by six times over the last 20 years.

"There's a demand for fish protein," said research scientist Cyr Couturier of the Marine Institute at Memorial University of Newfoundland.

Couturier's research focuses on reducing the environmental impact of aquaculture.

He says he's not surprised beef has fallen behind food produced on fish farms.

'I think farmed fish will be part of the answer in terms of food supply.'—Janet Larsen, research director, Earth Policy Institute

"It's a good healthy source of animal protein, and I think that's another reason why there's a drive to produce more on the planet," Couturier said.

Everything from fish to seaweed and shellfish is farmed today. And not surprisingly, China leads the world in aquaculture.

"I think farmed fish will be part of the answer in terms of food supply," said Janet Larsen, research director with the Earth Policy Institute in the U.S.

Aquaculture is the least energy-intensive means of producing animal protein, but not all fish farms are created equal, says Larsen.

Some threaten ecologically-sensitive areas while farming certain species, such as salmon, causes a drain on wild fish.

"We're overfishing a lot of our smaller fish stocks like menhaden, herring or sardines so that we could grind them up into fish meal and fish oil to feed to these farmed fish," she said.

Larsen predicts that, for the first time, more fish and seafood will be produced on farms this year than caught in the wild, meaning the need for sustainable aquaculture is greater than ever.