SOCKEYE SALMON- Safety Net

Over the course of their lives, Sockeye salmon carry out a migration of some two thousand miles. It’s a hazardous journey, so the Sockeye have evolved a kind of genetic safety net which could preserve the species if the migration were to fail. I’m Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Paul Kline is with the Idaho Department of Fish and Game. He tells us that, come Spring, most of the Sockeye salmon will begin their long migration from Idaho to the Pacific Ocean. A small portion of the fish, however, will stay just where they are.

“There is a form of Sockeye that we call residual Sockeye, that are resident to Redfish Lake. They are produced by the ocean going kind, but they select a life history of staying in the lake. And that’s a wild, natural life history safety net to protect the species in case there are environmental bottlenecks that may affect or threaten them.”

But if this migration is so dangerous, why don’t all Sockeye salmon live out their lives in the safety of Redfish Lake?

“While that residual element that stays in Redfish Lake that is produced by the ocean going kind is very important, the population does not develop the genetic diversity or variability that it needs to survive over a long term, just with that resident element. So you need both the ocean going form in addition to the resident form to guard against bottlenecks.”

So while most Sockeye salmon will migrate, they’ve also evolved a protective measure in case the migration fails. And, as we’ll hear in future programs, even this adaptation isn’t enough to protect the salmon migration from human interference.

Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I’m Jim Metzner.

SOCKEYE SALMON- Safety Net

An evolutionary safety net may not be enough to save Sockeye salmon from extinction.
Air Date:10/18/1999
Scientist:
Transcript:

Over the course of their lives, Sockeye salmon carry out a migration of some two thousand miles. It's a hazardous journey, so the Sockeye have evolved a kind of genetic safety net which could preserve the species if the migration were to fail. I'm Jim Metzner, and this is the Pulse of the Planet, presented by the American Museum of Natural History.

Paul Kline is with the Idaho Department of Fish and Game. He tells us that, come Spring, most of the Sockeye salmon will begin their long migration from Idaho to the Pacific Ocean. A small portion of the fish, however, will stay just where they are.

"There is a form of Sockeye that we call residual Sockeye, that are resident to Redfish Lake. They are produced by the ocean going kind, but they select a life history of staying in the lake. And that's a wild, natural life history safety net to protect the species in case there are environmental bottlenecks that may affect or threaten them."

But if this migration is so dangerous, why don't all Sockeye salmon live out their lives in the safety of Redfish Lake?

"While that residual element that stays in Redfish Lake that is produced by the ocean going kind is very important, the population does not develop the genetic diversity or variability that it needs to survive over a long term, just with that resident element. So you need both the ocean going form in addition to the resident form to guard against bottlenecks."

So while most Sockeye salmon will migrate, they've also evolved a protective measure in case the migration fails. And, as we'll hear in future programs, even this adaptation isn't enough to protect the salmon migration from human interference.

Pulse of the Planet is presented by the American Museum of Natural History. Additional funding for this series has been provided by the National Science Foundation. I'm Jim Metzner.