But what if we want food to be cheaper, not just take up less surface area. After all, if so much of the ocean’s surface is being left unused, it doesn’t really matter what we put there as long as it is producing cheap food to feed the poor.
New seaweed farming methods have recently been developed in which seaweed is attached to a rope which is suspended as much as 100 feet down under the surface of the water. Using this extremely low cost method of farming seaweed it can be grown even in waters far too deep for it to ever touch the bottom, a great distance from shore. Seaweed in general is not a demanding crop to farm; after planting, farmers can simply leave it in the sea to grow until it is ready for harvest. It requires no fertilizers, pesticides, or other agrochemicals. A great deal can be grown in a short time: annual yields average 21 tons of dry weight per hectare. By comparison, about 12.1 tons of corn can be harvested per hectare in the highly productive fields of the United States.
At my local Walmart, I can go and buy a can of shucked, de-cobbed, washed and canned corn for about 89 cents per pound (you can try this yourself at your local grocery store and compare prices) so assuming that seaweed also reduces the need for most of the labor and machinery used in farming corn, let’s assume that we can cut that cost in half. That would mean that seaweed could be grown, processed, and sold anywhere in the world for only about 45 cents per pound, and still the areas growing it would be producing more in raw quantity than either corn or potatoes could by comparison.
In most cases, the process of growing seaweed helps their nearby environment. They suck up nitrogen and phosphorus from the oceans, thereby reducing acidification and eutrophication of water bodies. They also capture carbon dioxide as they grow, which make them carbon-negative plants. By turning these chemicals into oxygen, they help to restore ocean dead spots.
Some large species of kelp grow even faster, with some farms producing as much as 25 tons per acre in only 5 months! Many of these large species of kelp can grow as much as 1 foot per day, meaning that instead of having only 1 or 2 harvests per year, harvests can be continual guaranteeing that consumers will have only the freshest ingredients at all times.
Not to mention, if we can get kelp farms consistently producing around 25 tons per acre every 5 months, we could feed the world’s population, cheaply, with an area of ocean only the size of Washington state. Now imagine how little land we would need if we could drop salmon prices as well!