The sea is cerulean blue. The sea is green. Light falls on the water through storm clouds turning it as gray as steel. Waves hit the shore and when the water runs back into itself, beach stones rattle and jump.

A bright orange crab carapace, shucked in a growth spurt, spins in the current. It rolls over to reveal a smooth inner surface that is bright purple. Long tendrils of eel grass curl around it, as if making a nest, then another wave hits and all is obliterated in a foam of white water.

The waves have a cadence as soothing as a religious chant. But you cannot breath in time with the waves, nor match your stride to them. The sea has a rhythm all its own. And yet, as you walk along the shore, the ocean becomes part of you. It vibrates your internal ear and charges the air that fills your lungs. It penetrates the cornea, changing light, setting treasures before you on the sand (a whorled hermit crab shell, a piece of driftwood that looks like a serpent’s eye, a white rock as smooth as a sparrow’s egg) and then drawing them back with the next wave. Back into the unknowable mystery of the endless sea.

Geographers say there are four oceans in the world, and more than twice as many seas, but really there is just one, for they are all linked. The Pacific, which separates Asia from the Americas, joins the Arctic Ocean in the north and merges with the Atlantic and Indian Oceans to the south and east. So Chinese junks wash ashore on the West Coast of Canada, giant sunfish swim in from the tropics, and whales migrate through to the Bering Sea.

Along the ragged coast of British Columbia the world’s great ocean passes into a series of deep fjords, inlets, bays and straits, where the blue water reflects a dense green rain forest and is divided by dozens of islands, some with rugged shores, some with sweeping beaches of glacial sand. Here, between Vancouver Island and the mainland coast, lies one of the richest and most beautiful stretches of ocean on the planet. We call it the Strait of Georgia, in Canada, but thousands of years earlier, the native people who ranged along the coast had different names for it.

Whatever you call it, it is a rare, confined slice of a vast ocean network -- an inland sea that shapes life on the West Coast more than any other aspect of nature.

Millions of people are clustered along the Pacific Coast of North America. We use its waters as a transportation corridor, linking our ports to the ports of the world. We use it to haul log booms and other coastal freight, we fish in it for salmon, cod, herring and even krill. We sail on it, swim in it and wherever possible situate our buildings so that we can bathe in the light that reflects off it.

For all our dependence on the land, we are an oceanic culture.

And despite all that -- we pollute the sea and over-harvest its resources, driving stocks of salmon, ling cod and abalone to endangered levels; stripping shorelines of aquatic vegetation with caustic industrial waste and making beaches unhealthy with sewage.

As our population grows, living with the sea becomes an increasing challenge. In other places, the Sea of Cortez, the Gulf of Mexico, people are killing the waters that they love, turning vast areas into "dead zones" where nothing lives.

Here on the West Coast there are troubling signs that an incremental degradation of the Strait of Georgia has begun. Not the least troubling is the decline of salmon, which has been felt in California, Oregon, Washington, British Columbia and even Alaska.

Billions of dollars are being poured into habitat restoration projects in watersheds in two countries. The results are gratifying.

But while the governments of Canada and the United States are spending enormous amounts to rebuild salmon streams, they are simultaneously licensing commercial fishing operations that drag the seas with nets - or that scrape the bottoms in trawl fisheries, destroying everything to catch a few "desirable" species.

We know, as fishermen, that this doesn't make sense.

We say, let's stop this brutal, inefficient harvesting. Let's stop fishing down the food web, seining out herring, krill and other species that are vital as food for salmon. Let's stop polluting our oceans, killing salmon fry with our effluent. Let's stop penning Atlantic salmon in the open Pacific, where they can escape, infecting and competing with natural, wild, Pacific salmon.

We say taking care of our oceans is as important as taking care of our rivers and lakes. Because in the end, it is all linked together.

Look out over the sea, and before long gray rain clouds will gather. They will move the ocean inland, and it will flow back out again, forming the rivers we love to fish.

You do not need to be a coastal dweller to care about the sea. It is around all of us, all the time.