Contention 1 is Inherency – Overfishing has led to catastrophic declines in fish populations – aquaculture is the only sustainable way to produce fish
Walsh, 11 (Bryan, senior writer for TIME Magazine covering energy and the environment. Published July 7, 2011. Available at http://content.time.com/time/health/article/0,8599,2081796,00.html)
But we may be coming to that realization too late, because it turns out that even the fathomless depths of the oceans have limits. The U.N. reports that 32% of global fish stocks are overexploited or depleted and as much as 90% of large species like tuna and marlin have been fished out in the past half-century. Once-plentiful species like Atlantic cod have been fished to near oblivion, and delicacies like bluefin tuna are on an arc toward extinction. A recent report by the International Programme on the State of the Ocean found that the world's marine species faced threats "unprecedented in human history" — and overfishing is part of the problem.
Meanwhile, the worldwide catch seems to have plateaued at about 90 million tons a year since the mid-1990s. That's a lot of fish, but even if those levels prove sustainable, it's not enough to keep up with global seafood consumption, which has risen from 22 lb. per person per year in the 1960s to nearly 38 lb. today. With hundreds of millions of people joining the middle class in the developing world and fish increasingly seen as a tasty and heart-healthy form of protein, that trend will continue. The inescapable conclusion: there just isn't enough seafood in the seas. "The wild stocks are not going to keep up," says Stephen Hall, director general of the WorldFish Center. "Something else has to fill that gap."
Something else already does: aquaculture. Humans have been raising some fish in farms for almost as long as we've been fishing, beginning with Chinese fishponds 4,000 years ago. But it's only in the past 50 years that aquaculture has become a true industry. Global aquacultural production increased from less than 1 million tons in 1950 to 52.5 million tons in 2008, and over the past few decades, aquaculture has grown faster than any other form of food production. Today about half the seafood consumed around the world comes from farms, and with the projected rise in global seafood consumption, that proportion will surely increase. Without aquaculture, the pressure to overfish the oceans would be even greater. "It's no longer a question about whether aquaculture is something we should or shouldn't embrace," says Ned Daly, senior projects adviser at the Seafood Choices Alliance. "It's here. The question is how we'll do it."