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  • For 3 billion people around the world, seafood provides a significant source of protein and nutrition.

  • But recent studies show that 33% of wild fisheries are overfished, while another 60% are fished at their maximum capacity.

  • In fact, over half the seafood we eatfrom finfish and shellfish to seaweed and algaeisn't caught in the wild.

  • It's grown through aquaculture, or aquatic farming.

  • Farmed seafood is one of the fastest-growing food industries, expanding in volume by 5.8 percent each year

  • But different methods of aquaculture come with different advantages and issuessome of which echo the serious problems we've seen in industrial agriculture.

  • So how can we avoid repeating the mistakes we've made on land, at sea?

  • What aquaculture approaches are we currently using, and what does a sustainable way to farm the ocean really look like?

  • One of the most common aquaculture methods involves large pens made of nets, where fish are farmed offshore in floating cages roughly 1,000 square meters in size.

  • Commonly employed off the coast of Chile and in the fjords of Norway, these fish, like many industrially farmed animals, occupy stressful, overcrowded pens.

  • They produce massive amounts of waste, polluting the surrounding areas and potentially spreading diseases to wild species.

  • Worse still, since the antibiotics employed to fight disease aren't fully absorbed by the fish, they get excreted back into the environment.

  • Net pens are also susceptible to escapes, unleashing huge numbers of fish which compete for resources and weaken the local gene pool with genes adapted for captivity.

  • Escaped fish can even disrupt local ecosystems as invasive species.

  • Other techniques, such as man-made coastal ponds commonly used for shrimp farming in Southeast Asia, create additional environmental problems.

  • Just like net pens, these ponds are prone to spreading pollution and disease.

  • Their construction also frequently destroys important ecosystems like mangroves and marshes, which protect coastal areas from storms, provide habitats, and absorb tons of greenhouse gases.

  • One way to solve these problems is to farm fish on land in completely contained systems.

  • Tanks and raceways can recirculate and filter water to prevent pollution.

  • But even fully contained facilities still contend with another major hurdle: fishmeal.

  • About 10% of the seafood caught globally is used to feed animals, including carnivorous farmed fish.

  • Researchers are working on fish feed made of insects and plant-based proteins, but for now many inland fish farms are connected to overfishing.

  • All these obstacles can make sustainable aquaculture feel a long way off, but innovative farmers are finding new ways to responsibly farm the seas.

  • The most promising solution of all may be to look lower on the food chain.

  • Instead of cramming large, carnivorous fish into pens, we can work with natural ocean systems to produce huge amounts of shellfish and seaweeds.

  • These low-maintenance flora and fauna don't need to be fed at all.

  • In fact, they naturally improve water quality, filtering it as they feed off sunlight and nutrients in the seawater.

  • By absorbing carbon through photosynthesis, these farms help battle climate change, and reduce local ocean acidification while creating habitats for other species to thrive.

  • Shifting to restorative ocean farming could provide good jobs for coastal communities, and support healthy plant and shellfish-based diets that have an incredibly low carbon footprint.

  • In just 5 months, 4,000 square meters of ocean can produce 25 tons of seaweed and 250,000 of shellfish.

  • With the right distribution network, a series of small farms, collectively the size of Washington State could feed the planet.

  • Farms like these are already popping up around the globe, and a new generation of farmers is stepping up to pursue a more sustainable future.

  • Done properly, regenerative ocean farming could play a vital role in helping our oceans, our climate, and ourselves.

  • If overfishing continues at its current rate will the ocean run out of fish?

  • Check out this video to learn more.

For 3 billion people around the world, seafood provides a significant source of protein and nutrition.

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B2 US TED-Ed fish ocean farmed shellfish seafood

Could underwater farms help fight climate change? - Ayana Johnson and Megan Davis

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    Hon Man Fai posted on 2019/06/23
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