The Sea is Our First Home!

Have you ever seen a picture of the earth taken from a spaceship? If you have, wasn't its beautiful blue color incredible?

This beauty of our earth graced by the presence of water is what gives it other name, the "water planet." Among the other planets in the solar system, as far as we know, the earth is the only one with oceans. Mars has nothing but ice and on Venus the temperature is way too high for there to be any water.

There are many songs about the big wide sea. But just how big is the ocean? Let's find out.

Almost 70 percent of the earth is covered by the ocean and the average depth of water is 4,000 meters. That means that if, for example, Japan's tallest mountain, Mt. Fuji, was moved into the ocean, the water would cover it completely! The deepest ocean in the world is 10,000 meters deep. In this case, if you could stack up three Mt. Fujis, one on top of the other, and put them in the ocean, only the very tip of the top one would stick out!

The sea appeared on earth soon after the earth was created, and from it came the first signs of life. Human beings and other living things can all be traced back to the sea, meaning that it was our "first home." Even now, no matter how advanced our society becomes, all living things on earth, including us human beings, could not exist without the sea.

So, what kind of condition is our precious ocean in now? What's the relationship between us people and the sea?

The sea has many purposes such as supplying food, energy and various resources. It is also used to transport people and goods. Finally, it helps balance the climate of the entire world and releases oxygen into the atmosphere.

Now let's take a look at food that comes from the sea.

How often do you eat fish? The average Japanese person eats 70 kilograms of fish per year. Compare this to the rest of the world that has an average of just 15 kilograms per year. So this means that Japanese people eat nearly five times the amount of fish eaten by other people around the world! Since the sea surrounds Japan, fish (along with rice) has been the most commonly eaten food in that country.

Fifty years ago, the total weight of fish caught in a year (the global fish catch) was 1,900 tons. But technological developments in the world's fishing industry, such as fish detectors and boats, called trawlers, which pull huge nets behind them, have made it possible to catch huge numbers of fish at once. The global fish catch skyrocketed to nearly 90 million tons in 1989 but ever since then, that number has been getting smaller. Meanwhile, the world's population has gone from 2.5 billion people 50 years ago to 6.4 billion today.

Next, let's compare the world population with the total global fish catches of the last 50 years. Up until ten years ago, the amount of fish caught from the sea, per person, grew from 7.5 to 17 kilograms. However, over the last ten years, while global fish catch has stayed the same, the population has quickly grown. So, the amount of fish per person is slowly shrinking. Can you think of ways we help protect fish in the sea?

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