Treasures of the sea and the Blue Economy

You know natural resources from land: soil, forests, minerals. The ocean is a giant storehouse too. Anything in the ocean that is useful or valuable to us is a marine resource. They come in two groups (Fig. 1.17):

• Living resources: fish; useful natural substances from sea creatures (bioactive natural products, used for things like medicines); other sea creatures (marine bio-organisms); and plants that grow under the water (submerged aquatic vegetation). Fish that live over the continental shelf, from 0 to 200 m deep, are coastal (neritic) fish; those beyond the shelf, deeper than 200 m, are oceanic fish.
• Non-living resources: minerals; and energy: conventional (oil and natural gas), non-conventional (biofuels and gas hydrates), and ocean energy: tidal, wave and current energy, offshore wind, and OTEC (Ocean Thermal Energy Conversion, which makes power from the difference between warm surface water and cold deep water).

Why they matter (Fig. 1.18):

• Food and jobs: fish are a big source of protein, and fishing and fish farming (aquaculture) feed millions of families.
• Materials: sand and gravel, and minerals from the deep sea floor.
• Energy: oil and gas under the sea, and clean blue energy from tides and waves.
• Trade and tourism: about 90% of world trade by volume travels by sea, and coastal tourism earns billions.
• Culture: the sacred conch (shankha) and cowrie shells (kapardika), once used as money, are seen as treasures from the Samudra Manthana.

Countries with long coasts, like India, gain the most. But if we take too much, the sea runs out. Use the sea like a good tenant uses a house: take what you need, and hand it on in good shape.

The Blue Economy. The World Bank's idea: use ocean resources so that the economy grows, people get better livelihoods and jobs, and the sea's ecosystems stay healthy, all three together. The UN's Sustainable Development Goal 14, 'Life Below Water', sets the aims:

• cut marine pollution;
• protect marine ecosystems;
• tackle ocean acidification (the sea turning more acidic);
• regulate fishing, so fish are not caught faster than they can breed;
• conserve marine areas;
• end harmful subsidies (government money that encourages over-fishing);
• increase the economic benefits people get from the sea.