SAN GREGORIO -- This flat, arrow-straight section of San Gregorio Creek near La Honda looks perfectly healthy to the untrained eye, but biologist Jon Ambrose sees there is something amiss.
The streambed is too plain -- too tidy. There are no fallen trees or logs in the water, which has slowed to a late September near-trickle.
Though a lack of debris may sound like a good thing, it's disastrous for an ancient resident of these waters who recently disappeared: the coho salmon. The species relies on the wood to create deep, cold pools of water where they can escape the heat and hide from predators.
"You should not be able to drive a truck down a creek that's in a redwood forest," said Ambrose of the National Marine Fisheries Service, looking out over the creek. "And right now you could."
The lack of downed trees in San Gregorio and other creeks -- the result of well-meaning landowners either cleaning up or trying to prevent flooding -- is one of many reasons for the slow extirpation of the Central California Coast coho salmon. The spawning runs of these oceangoing fish helped sustain human life in the Bay Area for thousands of years, but their numbers dropped sharply with the arrival of Western settlers. Their population has since collapsed from about 56,000 in the 1960s to perhaps a few thousand today.
To combat this decline, the National Marine Fisheries Service spent five years compiling an encyclopedic recovery plan for the Central Coast coho. The fish is an evolutionarily significant unit, or regional subset, of the Pacific coho, which is found as far north as the Bering Sea. Smaller than its relative the Chinook salmon, the coho avoids big river systems in favor of creeks. Once abundant in streams from northern Mendocino County to Santa Cruz, the Central Coast coho was listed as endangered in 2005 and is now on the verge of extinction.
The plan, a roughly 2,000-page tome that lays out specific recommendations for 28 watersheds on the Central Coast, was released in September. Now comes the hard part: making it happen. The strategy, which would cost $1.5 billion to pull off, is purely advisory and comes with no extra funding.
Sam Herzberg, a San Mateo County parks planner and director of a group of Central Coast officials focused on coho and steelhead trout recovery, supports the plan but is skeptical whether it will be effective.
"It's got no mandates and no money to implement any of (the recommendations)," he said.
Ambrose, an author of the plan, said it will nonetheless serve two crucial functions. First, it will funnel existing sources of money as well as the energy of government and private entities toward the most effective recovery projects. Second, the plan will help educate private landowners about how to manage their portions of creeks where coho have historically been found.
The plan argues there are societal and economic benefits to reviving the coho, which has long served a vital role in human culture on the Pacific Coast. Restoration projects create jobs as well as benefit other fish species such as steelhead trout, the plan's authors contend. Creating sustainable coho and steelhead populations would give a boost to fishermen and enhance coastal tourism.
For those who work to save the coho, the plan is not only a blueprint for recovery but also a long-awaited call to action. Kellyx Nelson, executive director of the San Mateo County Resource Conservation District, hopes it captures the public imagination the way a famed campaign to save California condors did after the bird's population dropped to just 22 in the 1980s.
"The coho needs a California condor moment," Nelson said.
The recovery plan identifies nine creeks south of the Golden Gate that are essential to pulling the coho out of the extinction vortex: three in San Mateo County and six in Santa Cruz County.
The status of coho in the San Mateo County creeks is especially dire, according to Ambrose. Monitoring has been spotty, he said, but Pescadero Creek is believed to have none. San Gregorio Creek hasn't had any since 2008, and the 2010 and 2011 spawning runs in Gazos Creek failed.
The causes of the Central Coast collapses are varied but include:
Along San Gregorio Creek, for instance, 98 percent of the land is in private hands. Brussels sprouts farmers and homeowners along the creek have the right to take water from it using metered pumps. Portions of state Highway 84 that eroded have been reinforced with stark rock walls. The road has destabilized slopes along the creek, causing sediment to wash downhill during winter storms.
Here and elsewhere, a simple thing like removing wood from the stream, repeated hundreds of times over many years, has serious consequences. Fallen trees and logs push water down into the streambed, scouring out deep pools for juvenile salmon and sorting gravel by size, creating ideal spawning beds elsewhere in the creek. The wood also provides sanctuary during winter storms so juvenile salmon, which spend a year in the stream where they hatch before heading out to the Pacific Ocean, are not swept out before they are big enough to survive.
The recovery plan includes many recommendations, from establishing hatcheries and felling trees into streams to replacing old culverts and bridges that impede fish passage. But arguably the top job for Ambrose and other proponents is informing landowners how to take small but significant steps to help the fish.
"It's really hard to motivate people to save a fishery when they don't even know it's there," Ambrose said.
One key method for improving coho habitat involves persuading landowners to use less water from local creeks or amend their water-diversion permits so they can store the water, rather than use it right away. This latter option allows people to remove water during wet winter months, ensuring there's more for the fish in the summer.
But that can be tough sell to wary landowners. And it involves a mess of bureaucratic red tape, said Nelson of the Resource Conservation District. One switch of a permit, she noted, can require approval from a handful of local, state and federal agencies.
"The irony to me," Nelson said, "is the extent to which regulations intended to protect natural resources inhibit our ability to protect natural resources."
And while some landowners may be amenable to pitching in for the coho, others will be harder to persuade. Ambrose acknowledged that distrust of government is common among rural landowners, who sometimes chafe at what they perceive as intrusive and burdensome regulations.
One way to deal with that issue is to involve third parties, such as resource conservation districts and farm bureaus, to work with the landowners.
"As time goes by people may not necessarily like us," he said, "but they come to realize that we're not there to shut them down."
Contact Aaron Kinney at 650-348-4357. Follow him at Twitter.com/kinneytimes.