Why spider webs glisten with dew (Nature, 02.03.2010)

•February 4, 2010 • 1 Comment

Two driving forces acting on wet spider silk help it to capture water.

Researchers have puzzled out how spider silk is able to catch the morning dew. Their findings may lead to the development of new materials that are able to capture water from the air.

The study, published today in Nature1, examines the silk of the hackled orbweaver spider Uloborus walckenaerius. “Bright, pearl-like water drops hang on thin spider silk in the morning after fogging,” says study author Lei Jiang from the Beijing National Laboratory for Molecular Sciences. “It is unexpected and interesting. Human hair can’t do that.”

Dry spider silk forms a necklace-like structure. Two main fibres support a series of separate rounded ‘puffs’, each made up of tiny, randomly intertwined nanofibrils. When water vapour condenses onto these puffs, they shrink into densely packed knots, shaped like spindles (or two cones with their bases stuck together). Thinner connecting stretches of nanofibrils, separating the knots, become more apparent; these areas are called ‘joints’.

The researchers studied the webs under both electron and light microscopes. They noticed that as water condenses on the web, droplets move towards the nearest spindle-knot, where they coalesce to form larger drops.

The spindle-knots have a rough surface, because the fibrils within them are randomly interweaved. But the joints between the knots have a smooth texture, because their constituent fibrils run parallel to each other. It is this difference in roughness that helps water drops to slide towards the spindle-knots, sticking when they arrive.

The cone shape of the spindle-knots also drives droplets towards their centre. Once they hit the edge of a cone, drops are propelled towards its base, the least curved region, because of the pressure difference caused by surface tension.

Mimicking nature

Guided by their findings, the team made their own artificial spider silk using nylon fibres dipped in a polymer solution that, when dried, formed spindle-knots similar to those in natural spider silk. They anticipate that their studies of these fibres could lead to new materials for collecting water from the air.

“It is impressive that they were able to produce an analogue of wetted [spider] thread that duplicated the properties that they observed,” says spider silk expert Brent Opell of Virginia Tech in Blacksburg.

But it doesn’t seem likely that natural selection has directed the evolution of this particular spider’s silk for water collection, he adds. The spider’s thread seems to have evolved to work best when it is dry.

As Jiang and his colleagues show, when the spider silk is wetted, the fibrils are matted down. “From a spider’s perspective, this is a bad thing because it reduces the web’s ability to capture prey,” Opell says.

“The authors of this paper are studying an artefact,” says zoologist and spider-silk expert Fritz Vollrath of the University of Oxford, UK, “which is still interesting although it has no biological function”.

1.  Zheng, Y. et al. Nature 463, 640-643 (2010).


Top 100 Stories of 2009 #31 “Sun’s Changes Have Surprise Effects on Earth’s Weather” (DISCOVER, January/February 2010)

•January 19, 2010 • Leave a Comment

Scientists have long suspected that the sun affects climate on Earth, but that connection has proved hard to pin down. Researchers recently demonstrated that the 11-year cycle of solar activity influences weather in the tropical Pacific Ocean. Even then the exact cause remained obscure, since the sun’s brightness varies by just one-tenth of a percent. Two studies from 2009 are filling in the gaps.

In August an international team lead by Gerald Meehl, a climatologist with the National Center for Atmospheric Research, announced that the sun’s outsize influence results from its combined effects on our atmosphere and oceans. When the sun is at its most intense, ozone in the stratosphere absorbs more ultraviolet energy, making areas near the equator warmer than usual. The added heat changes wind patters, bringing more rain to the western tropics. At the same time, the extra sunlight causes more evaporation off the ocean, which adds to downpours in the western tropics. Simulations that modeled just one of these effects failed to match the real world. Meehl saw that the two mechanisms “feed off each other, producing a stronger response than either can alone.” His results should help climatologists predict monsoons in Asian and overall climate in North America and might someday allow them to estimate seasonal rainfall years in advance.

Meanwhile, Henrik Svensmark of the Technical University of Denmark and his colleagues are exploring a broader climate impact of solar activity. He believed that cosmic rays—energetic subatomic particles from outer space—help seed could-forming water droplets in the lower atmosphere. During peak solar activity, eruptions from the sun spew out huge clouds of plasma that shield Earth from those cosmic rays. After examining could cover and cosmic ray fluxes, Svensmark concluded that declines in cosmic rays lead to fewer clouds, implying that an active sun could lead to warmer surface temperatures. Following the strongest solar eruptions, he found that the sky lost 7 percent of its cloud water. Many scientists doubt the significance of these cosmic ray effects, but Svensmark sees the question as ripe for investigation. “The sun is doing natural experiments on Earth’s atmosphere, giving us the opportunity to test these ideas,” he says.

Top 100 Stories of 2009 #41 “Strange Gaze of the See-through Fish” (DISCOVER, January/February 2010)

•January 19, 2010 • Leave a Comment

© 2004 MBARI

The barreleye fish has eyes that gaze upward right through a transparent shield covering its head. This year ecologists at the Monterey Bay Aquarium Research Institute studied the first-ever underwater video of the strange fish. They also managed to recover one alive and get a good look at that shield, which may protect its eyes as it steals prey from stinging jellyfish.

On Global Geodynamics and Earthquake Forecasting: An Interdisciplinary Approach (LDEO News, Winter 08/09)

•July 3, 2009 • Leave a Comment

From the sudden, violent motion of a single earthquake to the more gradual convection of its interior over millions of years, Earth is a dynamic planet.

Geodynamics—the study of the forces and processes driving Earth’s tectonic plates—is an integrated science that draws from geology, geophysics, technophysics, seismology, fluid dynamics, and petrology. It’s natural for Lamont-Doherty scientists—enabled by the tradition of interdisciplinary studies and the breadth of expertise here—to pursue some of the most complex questions in geodynamics. With a combination of observation, theory, computation, and laboratory experimentation, they have begun to illuminate the most difficult problems and to provide the most relevant constraints.

Nowhere does this effort have more impact on society than when significant earthquakes occur. Large earthquakes are among the richest phenomena on our planet, and to study them provides insight not only into their hazard and risk, but also into the deformation processes in Earth’s crust and uppermost mantle. Questions pertaining to mantle convection and plate tectonic movement, formerly considered as two distinct scientific problems, are now being looked at as one coherent system.

It is incredibly productive to view the tectonic movements that triggered last spring’s earthquake in Wenchuan County—the Sichuan province of western China—in a geodynamic framework. Standard plate tectonics, in which rigid plates collide and generate earthquakes at well-defined boundaries, cannot explain entirely the forces that led to this disastrous event. Of course, the underlying cause is India’s collision with Asia, which has given rise to the Tibetan Plateau and the Himalayas. But rigid plate interactions are not sufficient to account for what happened in Wenchaun. Instead, a large body of work suggests that, in China and neighboring countries, the Eurasian plate is deforming internally. Much of this investigation has been an attempt to identify the nature of this deformation: Is it “platelike” (and thus explained by the localized shattering of the Eurasian plate into microplates), or is the deformation spatially continuous (thus behaving more like putty than pottery)? And which forces contribute to this unique style of deformation?

“Earth scientists want to know what happens at all scales—both geospatial and temporal—and how localized systems interact with larger, global ones,” says Ben Holtzman, a Doherty associate research scientist.


The 7.9-magnitude earthquake struck the semirural area outside of Chengdu at 2:28 p.m. on May 12, and aftershocks ranging between 4.0 and 6.9 on the Richter scale occurred over the next several days, weeks, and even months. Results were catastrophic, with more than 70,000 casualties. Most seismologists and engineers had estimated that ground tremors would reach only certain levels, and they built their civic infrastructure accordingly. “But the actual ground shaking recorded was three or four times greater than what had been projected,” says Arthur Lerner-Lam, associate director of Seismology, Geology and Tectonophysics at Lamont-Doherty. “How could we have been that far off?” he asks.
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The microbial biology of West Marin waste (Point Reyes Light, 04.16.2009)

•April 16, 2009 • 1 Comment


craptrap-1vacuumCow waste from Straus Family Creamery and human sewage from a Marshall manhole could help scientists develop better tests for the presence of harmful pathogens. Last month, Lawrence Berkeley National Laboratory postdocs Eric Dubinsky and Cindy Wu, assisted by Shariff Osman, conducted a census of poo microbes. Cattle and septic wastes were separately loaded into diffusion chambers—with semi-permeable membranes keeping bacteria in while allowing water and minerals in and out. The chambers were hung inside crab traps  (left top) and submerged into Walker Creek at Gale Ranch (below) and Tomales Bay by Nick’s Cove (above). At various time intervals, large syringes extracted the diluted wastes, which were then filtered under vacuum (left bottom) to concentrate bacteria onto disks and frozen on dry ice. Their DNA will be placed onto the PhyloChip—a new gadget developed by Gary Andersen that differentiates between 32,000 bacteria types. Current water quality tests don’t discriminate between contamination sources, leading to unnecessary beach closures and ranch restrictions. The team will determine which bacteria are unique to humans and which are unique to agriculture, and how those bacteria react in fresh versus salt water over time. Using that information, they hope to formulate a suite of indicator microbes that can accurately assess water safety.


District says it will spray everyone (Point Reyes Light, 04.09.2009)

•April 9, 2009 • Leave a Comment

In a move unauthorized by his board, the manager of the Marin/Sonoma Mosquito and Vector Control District cancelled the district’s No Spray agreement. Last week, over 500 Marin and Sonoma residents who were previously on a No Spray list received a certified letter stating that the list was replaced by a 48-hour notification system.

West Marin residents fear that Jim Wanderscheid’s decision violates a five-year agreement they have with the district that prohibits spraying other than during emergencies.

“People on the No Spray List don’t want just to be notified, they don’t want to be sprayed,” said Fred Smith, the district’s West Marin representative. “The district board of trustees never voted to eliminate the No Spray list. I plan to make sure it remains intact.”

The letter stated that residents would be given a 48-hour advance notice if their home is within 3,000 feet of an area scheduled to be treated for adult mosquitoes using a truck-mounted spray unit, or fogger. Advance notice would not be given before other control efforts, including hand-held adulticide sprays.

Last year, the board voted to implement a notification system. “I was assured that it would not affect the No Spray list,” said Sandra Ross, the Mill Valley representative. “There are people who for medical reasons can’t be sprayed. And the spray will get on window sills, the children’s play equipment and the dog’s drinking bowl.”

According to the letter, the district will assume that residents are not interested in being notified if they do not submit their contact information by May 1. But the regular April meeting of the district, which would give people an opportunity to discuss the issue, has been cancelled. “The compounded problem is, the board won’t even meet before May 1,” said Frank Egger, the Fairfax representative.

The letter is unsigned, and the names of all the trustees are listed on the left-hand side. “I’ve had some irate phone calls, irate emails from people who say, ‘I saw your name on that letter, why did you do this to us?’” Egger said. “It’s kind of a shock to all of us. To have the manager make that decision without the board is inappropriate. I want to see the No Spray list expanded, not eliminated.”

Ross spoke with Wanderscheid after the letters were sent. “I said, ‘There are people who can’t get out of the way, and they have a right not to be sprayed.’ And he said, ‘They don’t.’”

A signature is required for residents to be included in the new notification program, but by signing the letter, residents acknowledge that there is no longer a No Spray list. “The No Spray list and the notification system are not the same,” Smith said. “I think of the two as complementary.”

Inverness Park resident Rick Gordon called it a catch. “The phrasing suggests that a response indicates acknowledgment that there is no longer a No Spray list, and non-response indicates that you don’t care to be notified about spraying. Sounds like a legal Catch-22.”
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Beyond the TV graveyard (Point Reyes Light, 04.02.2009)

•April 4, 2009 • 1 Comment


Thirteen thousand pounds of electronic waste—as much as two elephant seal bulls or five Prius hybrids—were dropped off at the Dance Palace on Saturday.

For over eight hours, Jesse Alcala, who grew up in Point Reyes Station and owns All About E-Waste in Martinez, collected obsolete or broken electronics and used batteries from hundreds of people, for free. All the electronic scrap was then sent to ECS Refining in Santa Clara, which will either remarket or recycle the waste.

West Marin’s e-waste fit onto 24 palettes of Gaylord boxes. Alcala is paid according to weight by ECS, a local e-Steward. “Everything gets broken down and remade in California,” Alcala said. “Nothing is sent overseas where kids are out there working for free, and they burn it like it’s okay.”

In order to strip e-waste for reusable parts, some developing countries burn off plastic to salvage metal. Carcinogens, neurotoxins and noxious fumes are released into the air, and refuse from the fires often drain into waterways. “What got me are the poor little kids slaving away out there. They shouldn’t be busting their butt for nothing and not knowing that it’s tearing up the earth,” Alcala said. “All that stuff in the air and in the water they drink can’t be good.”

As a leader in environmental regulation, California doles out money to promote and fund e-waste recycling. The Electronic Waste Recycling Act of 2003 reduced hazardous substances used in certain electronic products sold in the state and enacted an e-waste recycling fee.

Retailers collect an advance recycling fee from consumers for hazardous e-wastes—such as TVs, computer monitors and laptops and portable DVD players with LCD displays—that have toxic levels of copper and lead. These fees are turned over to the state. Effective this year, screens between four and 15 inches are charged a fee of $8; the fee for screens 35 inches and larger is $25. On Saturday, Alcala collected at least 137 TVs and monitors, some brought from as far as Bolinas.

An approved collector and recycler with California’s Covered Electronic Waste Recovery and Recycling Payment System, ECS is reimbursed by the state. Besides car batteries and copper wires from phone and laptop cords, everything Alcala collects is sent to Santa Clara. ECS processes scrap electronics by shredding and separating the components—ferrous metals like steel, precious metals, copper, aluminum and plastic. The steel and aluminum are recycled, and the copper and precious metals are sampled, prepared and sent to a smelter. The alloys and ingots are then ready to be further shaped.

Alcala receives 23 cents a pound for TVs and monitors and two cents a pound for electronic scrap. He and his wife, Audrea, started the company a year and a half ago. His plumbing, sandblasting and construction work began to slow down in the past few years, and when he went to recycle some old TVs, he learned about the electronic recycling from his friend, Charles Hurtado of Hurtado Recycling. All About E-Waste is Better Business Bureau accredited, and Alcala’s fleet now includes a Ford diesel F 350, a Jeep Comanche and a Ram 350. Alcala attended West Marin and Tomales High schools, but moved back San Francisco in the 1980s. One of his former teachers even dropped something off on Saturday.

“When we got here in the morning, there were already five cars lined up. We didn’t even have time to set up tables,” Alcala said. The 14-foot rental truck made three trips, and all his vehicles were loaded to the top.

Sony VCRs, Olympia typewriters, big cell phones from the early 1990s, fluorescent tubes and electronic toothbrushes covered the parking lot. Boxes labeled “JUNK” contained VHS tapes and cassettes that obsolete electronics once played. There was also a centrifuge, a FIRARD II therapeutic infrared light for arthritis pain and an Oscilloscope Type 545A for measuring frequencies. “I would use it to make a submarine set for a movie,” joked Joe Trejo, Alcala’s friend who came to help.

“People have been storing up stuff for years,” said John Sundberg, who shuttled between the Coastal Health Alliance and the Dance Palace in his Highlander. “The temptation to dump it haphazardly or squeezed it in with regular trash gets greater with time. Something like this makes it easy for us to do the right thing.”

Unloading fax machines and vacuum cleaners, Trejo said: “I pictured myself just sitting here, waiting, but people here are really conscious about the environment. It’s a sign of the area.”

Alcala added: “A man collected stuff from friends out of town and came back at least four times. One lady walked up with a hairdryer. It was a really good day.”

All About E-Waste Event will be at the Recycle Circus at the Dance Palace on April 19.

Tomales ranchers consider a field of wind turbines (Point Reyes Light, 04.02.2009)

•April 4, 2009 • Leave a Comment

Tomales ranchers are considering leasing land for the placement of wind turbines up to 20 stories tall. A Florida-based electric utility company has sent out feelers to gauge landowners’ interest, and some ranchers have already agreed to allow wind monitoring stations set up on their parcels.

“It’s a good idea but it needs to be done respectfully for the ranching community,” said Dominic Grossi, president of the Marin County Farm Bureau, which is generally in favor of clean energy, especially as a way to diversify income. “It can’t be too obstructive or interfere with the agriculture facilities and operations.”

Six months ago, representatives from Florida Power and Light approached a handful of individuals about developing wind energy. They were interested in a swath of land north of Tomales—in the wind corridor near Dillon Beach—south of Valley Ford and the Estero Americano.

“It’s a beneficial thing to make the area more diversified. If it could fly, it would be fine,” said Chris Cornett, whose parcel is on Fallon Road. Cornett would be collecting a check from the energy company if he rents out his land.

“They were getting our input to see how we felt about it,” he said. “I think it’s years away. You won’t see wind turbines here in the next few years, if it can even happen. They don’t have any go-ahead on anything.”

Cornett organized a meeting at Valley Ford town hall during the winter so representatives could address questions all at once. “They were just asking about leasing folks’ properties,” said Jeff Stump, easement program director for Marin Agricultural Land Trust (MALT). About 20 people attended. “Half of the people they approached are really skeptical about it, and the other half are open-minded about it,” said Cornett, who falls in the latter half.

Landowners at the meeting wanted more information than the Florida-based company could provide at the time. The company, on the other hand, couldn’t answer those questions without having a better sense of the project’s plausibility. “What they were looking for was an approval and to maybe get some long term leases going. They didn’t want to put their money into testing if everybody is against it,” Cornett said. “But everybody thought, ‘Go get permits and then we’ll see.’”

Florida Light and Power will need approval from the California Coastal Commission and the county. “The County of Marin is very interested in renewable energy, and I think that we all share a responsibility for developing new sources of energy that are less impacting on climate change,” said Supervisor Steve Kinsey. “They are proposing some very large wind turbine towers. I think they have a long, long, long way to go.”

According to Stump, there are a lot of hoops for the company to jump through, and MALT is one of them. “The process would start with MALT landowners coming to us,” he said.

Cornett added, “They’re not going to get any long term-leases until they come back with where and how many.”

Florida Light and Power has permission to test the wind and has secured short-term leases for test plots. Cornett is supplying a plot where a wind meter will be installed. There has to be a definite amount of wind blowing at a certain speed for a specific percentage of the time for the project to be worth it. If strong enough currents exist, there can only be one turbine per 50 acres, and they have to be spaced a certain distance from any dwellings.

The company currently obtains more than half of its electricity from natural gas, and they operate turbines in at least two of the main wind resource areas in California—the windfarm in Altamont Pass in Alameda County between Livermore and Tracy and the windfarm near Rio Vista in Solano County.

The Tomales project would probably supply power to local Pacific Gas and Electric.

There are two energy-producing windmills in Marin. Mark Pasternak, owner of Devils Gulch Ranch in Nicasio, faced opposition for his 80-foot windmill, which was approved in 2003. McEvoy Olive Ranch between Nicasio and Petaluma proposed one 210-foot wind turbine in 2005. The majority of the county planning commissioners voted against the windmill on account of its size—about as tall as a 20-story building—potential noise impact and, above all, aesthetics. In 2007, a much shorter, under 150-foot windmill on McEvoy Ranch was approved.

Bolinas Community Public Utility District proposed a windmill northwest of town in 2002; Inverness Public Utility District proposed developing wind energy in 1990.

“Obviously people want greener energy—they just don’t want to look at it and how it’s made,” Cornett said. “It would be like big windmills over the Point, I doubt people would want to see that. ‘Put that stuff somewhere we can’t see it.’”

Kinsey added: “There’s a critical policy issue that the community and county face reconciling our commitment to renewable energy with our longstanding passion for undeveloped viewsheds. In the foreseeable future, the thought of seeing windfarms like the Livermore Hills in West Marin is about as likely as a nuclear plant being built on Bodega Head.”

Abbotts plan (Point Reyes Light, 03.12.2009)

•March 14, 2009 • Leave a Comment


Point Reyes National Seashore has plans for a $2 million restoration of 300 acres of coastal dunes south of Abbotts Lagoon. It will use excavators to dig up European beachgrass and bury it in deep pits under at least three feet of sand.

“Dunes have been highly developed in California, and rare dune species are moving towards extinction,” said Ellen Hamingson, a vegetation biologist for the park.

The last remaining intact dune habitat in the park is south of Abbotts Lagoon, and it includes some of the largest expanses of rare native plant communities, such as the American dune grass and beach pea.

“Native dunes are becoming a rare thing on the coast,” said Cicely Muldoon, interim superintendent for the park. “It’s extraordinary habitat and any opportunity to restore it is good.”

The dunes are critical habitat to 11 species federally listed as endangered or threatened, including the Western snowy plover, Myrtle’s silverspot butterfly, which is golden brown with black spots, and the endangered plants beach layia and Tidestrom’s lupine.

“It’s an intersection of rare species and invasive species,” Hamingson said. The fleshy beach layia, with white and yellow flowers, and the Tidestrom’s lupine, with whorls of purple peaflowers, are overwhelmed by invasive plants.

Over 70 percent of these coastal dunes are dominated by two nonnative plants—European beachgrass and ice plant. Together, they are aggressively spreading in solid mats, making it hard for native annual plants to germinate. “It’s acres and acres of a few species,” Hamingson said. “There’s no species diversity.” The park began small patches of eradication in 2001.

European beachgrass—the tall perennial grasses rising up to six feet on the sand—and the ice plant—a succulent with daisy-like purple flowers—were both introduced to California in the late 19th century to help stop sand dunes from blowing onto roads and houses. Beachgrass roots reach 10 to 20 feet deep into the sand, and the stalks continue to grow even if covered by sand. Together with the ice plant, the beachgrass holds onto the sand, making it into a solid wall of dunes instead of the regularly spaced dunes that occur naturally.

“The nonnative plants have been reshaping the dune,” Hamingson said. “They change the structure of the dunes, making them higher and parallel to the beach, creating a solid wall that prevents the flow of sand.”

These dunes naturally occur perpendicular to the shoreline, with high and low areas. Dunes that are high and parallel to the shoreline prevent the opening of new areas available for native dune annuals, which, along with the plover, need open sand movement.

“Once we remove those two problematic invasives, the dunes will naturally move back into a more perpendicular alignment,” Hamingson said.

Dense swaths of nonnative plants take up nesting space for plovers, whose nests are just tiny indentations in open areas of sand where vegetation is usually absent. Removing the invasive plants would increase unvegetated dunes for nesting, increase corridors for foraging and protection of young and decrease predation by ravens and red foxes, according to park ecologist Lorraine Parsons, who presented on the project at the Red Barn on Wednesday night. Clearing out the invasive species will also increase dune habitat and foraging sources for the silverspot butterfly.

“The environmental assessment is dense, partly because of all the different kinds of mitigations for plants, butterflies, frogs, snowy plovers, wetlands, where we can or can’t work, when we can work where,” Hamingson said.

The report listed three options for restoring site, with work expected to begin in 2010. One alternative is to take no new action, to only continue the current small-scale techniques used on increments of land. Another alternative would cost about $21 million and would combine treatments including prescribed burning, herbicide, hand removal and mechanical excavation.

The preferred alternative is mechanical excavation and deep burial, with potential treatment of resprouts with targeted herbicide use. Excavators will dig out clean sand and create a pit at least nine feet deep. Beachgrass and its roots will be dug up, the invasive mass will be dumped into the pit and buried under at least three feet of clean sand. Bulldozers could be used to level the cap of clean sand.

Treatment would last 160 days, but maintenance could take about five years. Should there be resprouts, they would be removed by hand or spot-sprayed with herbicide. “That would be one person going out with a backpack and spraying directly on a plant,” Hamingson said.

“There will be negligible to minor adverse impacts to rare plants, with minor to major long term benefits,” Parsons said.

Four years ago, park staff experimented with various methods on a patch of 50 acres. “Using hands to dig up roots that deep is challenging,” said Hamingson. “And the level of follow-up needed is hard to manage because of regrowth.” With hand removal, staff had to return 17 times. “In smaller areas or newer patches, it might work, but there are things you can’t scale up to 300 acres.” These experiments indicated that the most effective treatment for restoring dunes is to remove all the invasive biomass and bury it underneath clean sand.

Restrictions will apply. No heavy motorized equipment may be used within 500 feet of nesting plovers. “The park has been intensively surveying and monitoring the beach for plover nests for years,” Hamingson said. Should herbicides be used, it would only be in areas with wind speeds less than 10 mph and with buffers to wetlands, nesting areas and rare plants.

Snowy plovers breed, nest and rear between March and September, the silverspot butterfly adults actively feed between June through August. “There isn’t a lot of flexibility with these sensitive species in terms of their timelines,” Parsons said.

Public comments on any aspect of the report and proposal will be accepted until March 20. Comments can be submitted online at http://parkplanning.nps.gov, emailed to pore_planning@nps.gov or faxed to 663.8132, or mailed to Superintendent, Point Reyes National Seashore, 1 Bear Valley Road, Point Reyes Station, CA 94956.

No salmon up the creek (Point Reyes Light, 03.05.2009)

•March 6, 2009 • Leave a Comment

Only a handful of fish were found in the Lagunitas Creek watershed this winter season—making it the lowest coho count on the record for Olema Creek.

Coho salmon—listed as endangered since 2005—return to spawn in creeks between November and late February, known as the spawner year. This is the fourth year of observable decline in the endangered coho salmon population in Olema Creek—a decline some believe has resulted from unfavorable ocean conditions and late winter storms.

“We know that quite a few fish made it out to the ocean. The return rates were just really low,” said Michael Reichmuth, a fishery biologist with the National Park Service, who just conducted his third coho salmon survey this winter.

“This year, what we normally see in the early summer is what we’re seeing in December and January,” Reichmuth added. “We ran out of water, which caused passage issues. The woody debris jammed, and fish couldn’t get around that during low flow.”

The total coho count for the season was two redds (or nests) and three fish observed on Redwood Creek, and two live coho with only one coho redd observed on Olema Creek. Last year’s counts were just as gloomy.

Between eighty and 180 return to Olema Creek from the ocean every year. During the 2004-05 spawner year, Olema Creek had at least 184 fish—but the numbers have decreased ever since. However, there is not enough data to statistically show a declining trend outside of the regular fluctuations in the population.

Survey cycle

After adult females lay their reddish-orange eggs in gravel at the bottom of the creek, they die. During spawner surveys this winter, Reichmuth and his volunteers counted live adults, carcasses and redds.

When the salmon hatch, they find their way six inches down into the gravel and emerge a few weeks or months later. This summer, Reichmuth will conduct snorkel surveys to count those fish that were spawned this winter. “Based on what we see in the summer, we can infer what happened in the winter,” he said. It will help him determine how successful the spawning was. After they emerge from the gravel, those young salmon will spend one year in freshwater creeks. Then in the spring, these 4-inch-long juvenile salmon—now called smolts—to out into the ocean.

Beginning mid-March, Reichmuth will use traps to catch smolts as they embark on their migration out to sea—it tells his how successful the spawning was during the 2007-08 spawner year. And it gives him an idea of how many fish he’ll be expecting to return in a year and a half—or spawner year 2010-11.

According to the 2007 trap numbers, plenty of smolts were seen leaving the creek system. “We know that a good number of smolts left and went into the ocean,” Reichmuth said. They grow in the ocean for a year and a half before coming back to the creeks to spawn. The juvenile fish that left in 2007 are the ones that should have returned this winter to spawn.

Coming back

Even though a good number of smolts swam out in 2007, they were greeted by poor ocean conditions. Upwelling in the ocean brings up nutrients and increases productivity. Instead, those fish faced reduced currents and a lack of upwelling. And they couldn’t find food when they first went into the ocean.

If they did survive for a year and a half in the ocean, there are still several obstacles to survival before returning to spawn in the Lagunitas Creek watershed this winter.

Before these recent storms, seafaring coho spawn had to deal with drought conditions before they could return to freshwater streams. “They might have come towards the creek too early,” Reichmuth added. “Well, normal timing for them, but early relative to the late storms we had.” The lack of rain forced low flows, and the fish simply couldn’t make it into the creek.

If there were high numbers of fish holding out near the coast waiting to come into the creek, predators, like seals and sea lions, could pick them up before they can swim in. “I’ve seen otters wait right at the mouth of Olema Creek,” Reichmuth said.

Likely, it was a combination of poor ocean conditions and the late storms. “A lot of salmon went out, but not a whole lot of spawners came back, and on top of that, without enough rain, the ones that do come back can’t even get into the creek,” Reichmuth said.

But 2008 had favorable ocean conditions—lots of upwelling and good currents. Reichmuth expects better returns in 2009-10, especially if the rains come at the right period of time.

“We are now past the typical window for coho spawning, and I don’t expect to find any new Coho spawning activity even after this last set of storms,” Reichmuth wrote in an email to his volunteers.

The late rains this winter could still help. Reichmuth will conduct another spawner survey next week, when the water clears up after this week’s storms, and there will be better visibility. Surveyors in Scott Creek near Santa Cruz, who have coated fish with tags that act like FasTrak on cars, have picked up signals that coho have gotten into creeks south of Lagunitas Creek watershed during the recent larger storms.

“There’s still enough water that if the fish want to come up, they will,” Reichmuth said. “Right now, the streams are pretty much wide open. I’d like to be surprised.”

For volunteer opportunities within the Point Reyes National Seashore, visit http://www.nps.gov/pore/supportyourpark/volunteer.htm