Why Are Coho Salmon Disappearing?

After the rains finally fell this year, Scott Creek in the Santa Cruz Mountains roared back to life. And with it, the renewal of a timeless drama beneath these waters -- the salmon coming home and exhausting themselves to reproduce.

Sean Hayes: "About three weeks ago, she would have looked like your perfect, beautiful, silver salmon."

Sean Hayes and Bruce MacFarlane have a vested interest in this stream. They come here to count the returning steelhead and coho salmon. The numbers, not like they used to be.

Bruce MacFarlane: "Coho populations probably were in the hundreds and now they're in the tens."

It's another possible effect from climate change -- a product of Pacific Ocean warming that limits the southern range of these fish. It's especially crucial for the coho which have an absolute lifespan and timeline.

Bruce MacFarlane: "They're locked into three years. They've got to be able to get into their stream at three years to spawn. The stream has to have enough water, the quality of the water has to be good enough."

It's not so much a matter of coho salmon surviving as a species, but coho salmon surviving on this creek. It is all about the food chain. If the coho disappear, who knows what may follow next.

In order to give the salmon their best chance, MacFarlane and Hayes now help them with what amounts to an elaborate insurance policy. For many of these fish, life begins in a hatchery, upstream.

Bruce MacFarlane: "Each of those jars has the fertilized eggs from one fish."

But science played a large part in deciding which fish.

At a database in their Santa Cruz lab, each envelope has part of a fin containing genetic material. Before breeding any two fish, MacFarlane runs a match to assure that they are not related. He's looking for biological diversity.

Bruce MacFarlane: "We want a strong fish. We want a strong population."

Those fish get a good start. In this pond alone there are some 45,000 of them. And while hatchery fish tend not to be as hearty, they do retain their wild genes. Most will go downstream.

But each year, MacFarlane and his crew will keep a few as brood stock in case of a dry winter. They estimate that each of these salmon is worth about $20,000 dollars in time, research and labor.

Bruce MacFarlane: "No fishing is allowed here. You can't get a fishing permit for this pond."

On Scott Creek, nature has her way and the fish do return, with a little help from men.

Bruce MacFarlane: "I say they have an intrinsic right to be here, in and of themselves, and we know that they have a role to play because they have existed and they've gone on for as many years as they have. Who are we to reduce that diversity?"