Tuesday, January 05, 2010

Salmon & Streams

Most of us probably think of the larger rivers—which have mostly been dammed to provide water for communities and agriculture—when we think of spawning salmon, but many make their way up the smaller rivers and streams to spawn, and this story from Coast and Ocean examines how many of these smaller spawning areas are being enhanced for the salmon; which is very good news.

An excerpt.

“In 2001, a small miracle occurred in a stream south of the city of Arcata: the salmon came back. Lots of them. The stream, called Morrison Gulch, flows into Jacoby Creek, which empties into Humboldt Bay. Biologists knew it had once been spawning ground for salmon, because for several years they had counted hundreds trying to make their way upstream to mate--600 in one winter alone.

“But an old culvert under Quarry Road blocked the way; not one fish could make the jump into it from the pool below. Faced with such a barrier, some fish will try to find other places to spawn; others will die of exhaustion from their futile attempt to reach historic spawning grounds.

“Then, in August 2001, the County replaced the Quarry Road culvert with a wider one and regraded the stream above and below to raise the channel, allowing the fish to move freely through the new culvert. With the barrier gone, the salmon moved right back into the stream. That winter, biologists counted 70 coho returning to spawn, and the following winter they observed 238 adults and 116 redds (spawning nests).

“What happened in the Jacoby Creek watershed is happening, or beginning to happen, in many watersheds along the coast from Del Norte County to Monterey. In the past ten years, through collaborative efforts by counties, state and federal agencies, private landowners, and nonprofit organizations, almost 300 miles of streams have been reopened to salmon and restored to conditions favorable to the fishes' survival. At a time when everything else seems to be going wrong for West Coast salmon, this achievement is a ray of sunshine.

“Culverts and other small stream barriers may seem trivial compared to the large and intractable difficulties salmon face--drought, water diversions, hydropower dams, changes in ocean productivity--but there are so many of them that they have effectively locked fish out of huge areas of spawning habitat. A 2004 report by the Coastal Conservancy identified more than 19,000 barriers in California's coastal watersheds, at least 1,400 of them severe or impassable.

“Even obstacles that are not completely impassable to adult salmon can exhaust the fish before they reach spawning grounds, or keep juveniles, which can't jump as high as adults, from reaching tributaries that serve as safe havens during floods. "It's a huge problem," said Tom Weseloh, North Coast manager for California Trout. "If you've got a barrier at the mouth of a watershed, the whole watershed is impaired."

“Long before people knew about the life cycles of anadromous fish, they understood that salmon needed to be able to move freely up- and downstream. In his 2003 book King of Fish: The Thousand-Year Run of Salmon, geologist David R. Montgomery wrote of a 12th-century English statute requiring that English rivers "be kept free of obstructions so that a well-fed three-year-old pig could stand sideways in the stream without touching either side." Pigs were not at issue; the purpose was to protect salmon.

“Despite many such laws and restrictions over the centuries, the needs of fish have rarely been considered when roads and other structures were built, until recently. In California's early days, many coastal roads were cut right next to creeks for the logging industry, and streams were constricted and blocked by pipes and culverts. In 1935, federal fisheries biologists surveying streams in the Klamath and Shasta National Forests reported that culverts were cutting off salmon from the Klamath River and other main streams, and recommended that small bridges be used instead. They were ignored.”