Seaweed Farming

Seaweed production is on the rise worldwide, but people in North America have yet to embrace it as a food. That’s a shame, because it’s surprisingly powerful in the fight against water pollution and overfishing.

One of the major advantages of vegetarianism from an ecological perspective is that plant foods are far more efficient to produce than foods from animal sources. They require fewer harmful pesticides and fertilizers and smaller amounts of land.

But conventionally grown plant foods can still take a big toll on the environment. Imagine a food that could be grown without pesticides, without plant food or fertilizers–and without land.

That food is seaweed, and it’s set to have a profound impact on the future of environmentally responsible food production.

Aquaculture is the fastest growing food production activity in the world. In 2008, worldwide production of seaweed was around 16 million metric tons, worth about $7.5 billion. A small amount of this seaweed is used in cosmetic products and as a gelling agent, but in East Asia, where most of the production takes place, seaweed is overwhelmingly used as a food source. Seaweed is packed with protein, iron, vitamins A, B and C and a wide variety of healthy phytochemicals.

Seaweed is disarmingly easy to cultivate. For every temperature and depth of water there’s a suitable variety that will naturally thrive. Seaweed farms use thick lines or rope suspended in the water, a little like shellfish farms. The lines are seeded with seaweed of the appropriate type, then submerged in open tracts of the sea and left to themselves. All that’s required at harvest time is either chopping off the seaweed at the right length (allowing it to regrow for later harvests) or pulling up the lines entirely and then replanting from scratch. Some species of seaweed being grown in California are so bountiful that they can be harvested five or six times per year.

Not only does seaweed cultivation not require any pesticides or fertilizers, it actually improves the quality of the water it’s grown in. Brown seaweed fixes nitrogen, so harvesting it can clear areas of water polluted by nitrogen fertilizers from urban or agricultural runoff. Seaweed farming can also help protect vulnerable coral reefs by increasing the diversity of local algae.

Seaweed farming is also important environmentally because it encourages local people to protect and value their sea water and its resources. In less developed countries, seaweed farming is an essential source of employment and local food production. This eases pressure on local fish stocks and can reduce overfishing by reducing the economic necessity of fishing to survive.

Although the vast majority of seaweed production still takes place in countries like China, Japan and Indonesia, it’s slowly becoming more popular in the West. There are a growing number of seaweed farms in the US and Canada. But the biggest hurdle to overcome is increasing demand for fresh, unprocessed seaweed as a food. North American seaweed production contributes to the production of fertilizers and even biofuels, but if cultivation is ever to become a mainstream form of aquaculture, people will have to develop a taste for eating seaweed.

While Japanese processed seaweed products like nori are gradually becoming more popular, most people in North America have almost no experience of cooking with or eating seaweed in its natural form.

Hopefully this will change as seaweed farming becomes more popular and local communities begin to realize the health and environmental benefits of a locally sourced, pesticide and fertilizer free, renewable food source that can actually improve the local environment.

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