From MotherJones.com:

 “Globally, we’ve hungered for 3.2 percent more seafood every year for the last five decades, double the rate of our population. Yet more than four fifths of the world’s wild fisheries are overexploited or fully exploited (yielding the most fish possible with no expected room for growth). Only 3 percent of stocks are considered ‘underexploited’—meaning they have any significant room for expansion. If we continue to fish at the current pace, some scientists predict we’ll be facing oceans devoid of edible marine creatures by 2050.

Aquaculture could come to the rescue. The Food and Agriculture Organization of the UN predicts that farmed fish will soon surpass wild-caught; by 2030, aquaculture may produce more than 60 percent of fish we consume as food.

One of the most pressing concerns about aquaculture, though, is that many farmed fish are raised on a diet of 15 million tons a year of smaller bait fish—species like anchovies and menhaden. These bait—also known as forage fish—are ground up and converted into a substance called fishmeal. It takes roughly five pounds of them to produce one pound of farmed salmon. Bait fish are also used for non-food products like pet food, makeup, farm animal feed, and fish oil supplements.

It may appear as though the ocean enjoys endless schools of these tiny fish, but they too have been mismanaged, and their populations are prone to collapse. They’re a ‘finite resource that’s been fully utilized,’ says Mike Rust of NOAA’s Fisheries arm. Which is disturbing, considering that researchers like those at Oceana argue that forage fish may play an outsize role in maintaining the ocean’s ecological balance, including by contributing to the abundance of bigger predatory fish.

And that’s where Belov’s trout come in: Though he swears no one can taste the difference, his fish are vegetarians. That means those five pounds of forage fish can rest easy at sea. It also means that the trout don’t consume some of the other rendered animal proteins in normal fishmeal pellets: like bone meal, feather meal, blood meal, and chicken bi-products.”