If wishes were fishes

With our farming land running out, it's time to turn to the barren oceans to feed the world's poor, writes Ian Jones

Food does not just come from the land. Protein-rich food also comes from the ocean. At present, fish contribute 20 per cent of animal protein intake in low-income, food-deficient countries. But unlike the refined techniques developed to increase the yield from the land, the ocean is still treated as virgin territory only suitable for hunting and gathering.

Only in a few coastal areas have we introduced ocean farming.This mariculture has initiated the farming of monocultures but pollution and cost restrict this effort to producing food mostly for the tables of the world's billion rich citizens. The high cost ensures it does not contribute to the feeding of the poor.

In fact, much mariculture uses wild fish as feedstock.The sardines and other smallfish that could contribute to the diet of the poor are used to fatten the high-value carnivorous fish like salmon. Fattening carnivorous fish on wild stock is wasteful–it takes five kilograms of feed fish to produce one kilogram of salmon.

As the agrarian society has expanded, it has gained resources by clearing virgin land, and exploiting the environmental capital. The supply of land-based environmental capital is now almost exhausted. Feeding the extra two billion people requires us to lookfor unused environmental capital.

Vast, barren oceanic regions cover 70 per cent of the globe, while regions rich in sea life are restricted to the ocean edges. In these productive coastal regions, over fishing is endemic and fish consumption per head of population is declining. Could the desert regions of the ocean help feed the poor by providing low-cost protein?

We know that it is just a few simple elements, in particular nitrogen that limit ocean productivity over about 60 per cent of the sunlit regions of the ocean. The ocean would blossom if nitrogen, phosphorus and iron were provided to the surface. Intentional fertilisation of farmland is a long-established practice but the idea is novel for the open ocean.

Just as on the land, where scientists have demonstrated that the addition of certain missing nutrients lead to a greatly increased productivity, so it would be with the sea. Nitrogen in particular is in short supply in the sunlit regions of the ocean.

The production of food on land has doubled during the last 30 years. Careful introduction of ocean enrichment could double the wild fish catch during the next 30 years. This could be carried out progressively and in small regions so thatany unintended consequences could be limited. By increasing the base of the food chain rather than concentrating on one species, biodiversity could be maintained.

The not-for-profit Ocean Nourishment Foundation is championing this idea. It believes the ocean is our last environmental asset to address poverty. Doubling the fish catch would allow fish supply to the poor to stay constant despite population rises. But it is also necessary to bring the human population under control before this last resource is exhausted. Food security leads tofewer children per family. Provide food security and birth rates will decline.

But what about the cost? University of Sydney engineers have estimated the capital required to produce and deliver the nitrogen needed to increase marine protein production in the open ocean. This is far less per tonne of fish produced than is already invested in global fishing fleets to catch a tonne of wild fish.

The nutrients (fertiliser)would be delivered to 20-kilomtre radius patches of ocean away from the shore where large schools of sardines could fatten on the lush meadow of phytoplankton. Rather than expending effort searching for fish, fishermen could focus on enriched ocean areas where fish would gather. The capital invested in fishing vessels could return more income and vessels would expend less fuel per tonne of fish.

Strict management and radar surveillance of fishing in these marine feedlots would eliminate over fishing. The expense of producing and delivering the nutrients would only be a fraction of the value of the small pelagics fattened. Marine protein has high omega-3 content and small amounts of fish can provide humans with much of their protein. The enhanced phytoplankton growth stores more greenhouse gas than that generated from fossil fuel used in producing and capturing the fish, providing an additional benefit.

Yes, there are some environmental uncertainties. Learning by doing can reduce these uncertainties.Human malnourishment is a real and present danger while the uncertainties are yet to be revealed.