Mary Collins School teacher Blythe Shelley touching
a leopard shark at the Aquarium of the Bay

So, how do the Bay's leopard sharks, soupfin sharks, sevengill sharks, spiny dogfish, and other shark species differ from "non-shark" fishes? Here are a few key distinctions:

#1. You could say that sharks don't have a bad bone in their bodies. In fact, sharks don't have any bones in their bodies. Sharks-along with their relatives skates, rays, and ratfish-belong to a diverse class of fish that have cartilaginous skeletons, unlike the bony skeletons of other fish.

#2. Body shape. If you look at most fish head on, they have a generally oval shape. Sharks, in contrast, tend to be more triangular with a wide, flat under-surface. Their broad pectoral fins give them lift as they move through the water, not unlike the wings of an airplane. This hydrodynamic shape is key to keeping sharks afloat (you'll see why as we move on to difference #3).

#3. Besides bones, sharks lack the air-filled swim bladders that most fish use for buoyancy (If sharks are airplanes, does that mean bony fish are hot air balloons?) Instead, sharks keep afloat with the help of a large, low-density liver, their unique body designs, and the physics of forward motion. If a shark stops swimming it won't necessarily drown-only some sharks need to swim to breath-but it will sink!

#4. While most fish have gills tucked behind a bony flap called an operculum, sharks exhale water through gill slits located behind their head. Five gill slits are typical, but some sharks -like the sevengill shark found in the Bay-have more. Most sharks use ram ventilation to breath, swimming constantly with their mouths open to keep water flowing over their gills. Bottom dwelling sharks, whose mouths may be buried in the sand, inhale water through an opening on the top of their head called a spiracle and pump water past their gills.

#5. A shark's skin is covered with tiny dermal denticles that differ from scales on most fish. As their name indicates, they bear a physiological similarity to teeth. Their unique structure helps reduce drag as the shark moves through the water-in fact, sharkskin helped inspire the high-tech swimsuits we saw at the Summer Olympics.

#6. Most fish spawn by releasing large numbers of unfertilized eggs and sperm into the water. Sharks, in contrast, reproduce via internal fertilization. Depending on the species, they then lay a much smaller number of fertilized eggs, or carry the eggs inside until they hatch, giving birth to live pups.

Old Adobe Elementary teacher Juliet James examining shark teethSadly, these unique creatures are declining all over the world due to overfishing, pollution, loss of habitat from coastal development, and climate change. And that's bad news not just for sharks but also for their ecosystems. Like lions and wolves, most sharks sit atop the food chain as apex predators; thus their disappearance can trigger a cascade of disruption up and down the chain.

All the more reason for us to study up.

Harvey O. Banks Pumping Plant

In my last post I wrote about visiting a treatment plant to see where our water goes after we've washed the dishes. Now, on this tour of the Banks plant, I'm getting a glimpse "upstream" of the kitchen tap and learning more about where our water comes from.

The scale of the SWP is mind-boggling: More than two in three Californians rely on it for at least part of their drinking water. It is the largest publicly built and operated water project in the country, encompassing 17 pumping plants, more than 30 storage facilities, and over 660 miles of canals and pipelines. At the south end of the San Joaquin Valley at the Tehachapi Mountains, the huge Edmonston Pumping Plant raises the water 1,926 feet-the highest single lift in the world. (If you're driving to Southern California, check it out on the right side of I-5 just before the Grapevine). Moving all that water around and hoisting it over mountains doesn't come easy (water is heavy, after all): The SWP is the largest single user of electricity in the state.

The Banks plant is named for Harvey O. Banks, Director of Water Resources when voters approved funding for the SWP in 1960. The project was ostensibly conceived as a solution to the problem that most of California's water is north of the Delta, while most of its people are to the south and west. Big agricultural interests in the southern San Joaquin Valley also benefited-hugely-from "surplus" water shipped south. (And lest we Northern Californians start feeling smug, keep in mind we receive a greater percentage of our total water supply from the Delta than does Southern California.)

The Banks plant draws water from the Delta through intake gates into Clifton Court Forebay. From there, the water is pulled up a channel to the Skinner Fish Facility, where delta smelt, Chinook salmon, and some 90 other species of fish are, theoretically, screened out so they won't get sucked into the pumps (More on fish screening in my next post). But getting squashed in the pumps is not a fish's only worry: The pumping actually alters the habitat by impacting salinity and flow, disrupting natural rhythms that serve as vital cues for migration and spawning. The old joke that in California water flows uphill toward power and money is not far off the mark: The pull of the pumps is so powerful it causes rivers to flow backwards-literally uphill.

Crashing fish populations, poor water quality, the vulnerability of Delta levees and our water supply to earthquakes or other disasters-all have added to the growing realization that we can't keep quenching California's thirst through big straws stuck in the Delta. Obviously the SWP is not going to stop pumping anytime soon. But we do need to find ways to reduce our reliance on the Delta-through conservation, water recycling, and increased regional self-sufficiency-and to restore the functioning of an ecosystem so devastated by our radical retooling of our waterways.

To learn more about the travels of sewage, I took a tour of the Las Gallinas Valley Sanitary District treatment plant led by Plant Manager Matt Pierce. The plant has been in operation for about 50 years and serves over 30,000 residents in north San Rafael.

After leaving sinks and showers throughout the District, wastewater travels through a network of pipes and pump stations. Once the sewage arrives at Las Gallinas, it passes through an inlet screen and a grit chamber, which together remove much of the dense, inorganic material-"like diamond rings," Matt jokes.

A lot of what happens at the plant is not that different from what happens in your compost pile: "It's basically bacteria at work," Matt points out. (The much bigger challenge for sanitation districts these days are all the unnatural things we're putting down the drain: household chemicals, personal care products, pharmaceuticals.)

From the grit chamber the sewage heads into a series of clarifiers, where gravity causes the organic solids to settle out. The biosolids pass through a thickener and then an anaerobic digester-the most, ahem, aromatic stop on our tour. After further thickening in storage ponds, the sludge is injected into a disposal field.

Meanwhile, the liquid from the clarifiers travels through two biofilters, where rotating arms spray the water over rock beds. The organic matter in the wastewater is a feast for microbial slime living on the rocks. In the nitrification tower, more microorganisms break down the ammonia in the water. In the final stages of treatment, the wastewater is chlorinated to kill any remaining bacteria, then dechlorinated since the chlorine is toxic to many aquatic species. Finally, the treated water is sprayed onto District fields or discharged into Miller Creek where it flows to San Pablo Bay.

The District has done a lot to minimize the environmental impacts of its operations. The plant is powered by a field of solar panels. The methane released in the sludge treatment process is captured and used to generate power and heat the digester. Some of the treated wastewater supports acres of fresh and saltwater wetlands-in fact the District's land is a favorite local gem for walkers and birders. And in a partnership with the Marin Municipal Water District, more than a million gallons of treated wastewater are recycled daily for landscape irrigation and other projects.

There are plans to make even fuller use of the reclaimed water. The Bay Institute-in partnership with the Sonoma County Water Agency, Las Gallinas, and three other North Bay sanitation agencies-has developed a plan to use recycled water for wetland and creek restoration and for agricultural irrigation. Legislation sponsored by Congressman Mike Thompson to establish the program passed the House late last year; Senator Dianne Feinstein has introduced similar legislation that we are hopeful will pass this year.

With California's growing demands for water, such creative means to conserve and recycle are critical to helping prevent this precious resource from just going "down the drain."


Ann Dickinson is Communications Manager for The Bay Institute (www.bay.org), a nonprofit research, education, and advocacy organization dedicated to protecting and restoring San Francisco Bay and its watershed, "from the Sierra to the sea."

The California freshwater shrimp is 10-legged crustacean in the family Atyidae.

Found only in a handful of Bay Area creeks, the shrimp is a detritus feeder that prefers glides (calm, slow-flowing sections of streams) with undercut banks, exposed roots, and overhanging vegetation. Adult females produce relatively few eggs-about 50-120-that stick to the mother's pleopods during winter incubation. The young measure about 6 millimeters and are released in late spring or early summer. They grow rapidly, reaching up to 2.5 inches as adults and ranging in color from translucent to rusty red.

The species' closest cousin, the Pasadena freshwater shrimp (Syncaris pasadenae), went extinct in the 1930s, leaving the California freshwater shrimp as the only representative of its genus. The California freshwater shrimp was listed under the ESA in 1988. Recently the U.S. Fish & Wildlife Service issued its 5-year review of the shrimp's status. The report concludes that the species is not ready for delisting, as it still faces many of the same threats as 20 years ago: loss of habit due to agricultural activities and development, water pollution, water diversions-even the construction of recreational summer dams for swimming and fishing.

But there is also good news in the report. At the time it was listed, the shrimp was known from 17 streams; it now has been found in 23. In one of these, the number of shrimp surveyed increased from 1,878 in 1991 to 4,407 in 2000. Many of the streams in which the shrimp is found have watershed management plans in place. And the report also acknowledged the ongoing work of STRAW to restore more than 50,000 linear feet of stream bank, creating new habitat for the shrimp-not to mention other native species.

When Congress passed and Richard Nixon signed the ESA in 1973, a little freshwater shrimp was not at the forefront of their minds. But there is an inspiring sense of democracy in the ESA as written: It empowers citizens to petition or sue the government to protect species. And it doesn't discriminate between the big, showy species and the small and obscure-but equally unique and imperiled-ones.

According to the US Fish & Wildlife Service, since 1973 the ESA has protected 99% of listed species from extinction. National Endangered Species Day is coming up May 16. Find out about ways to help celebrate.

Ann Dickinson is Communications Manager for The Bay Institute (www.bay.org), a nonprofit research, education, and advocacy organization dedicated to protecting and restoring San Francisco Bay and its watershed, "from the Sierra to the sea."

Recent news headlines have been full of Chinook salmon, but sadly the same cannot be said of Central Valley waterways. This fall, only about 90,000 Central Valley Chinook salmon returned to their home rivers and streams to spawn, down from more than 800,000 just a few years ago.

Like most salmon, Central Valley Chinook are anadromous, spending the bulk of their lives in the ocean but hatching and returning to reproduce in freshwater. The journey from the Valley through the Delta and San Francisco Bay to the Pacific, and back again, has always been a long and arduous one. In the past half century it has become even more difficult as the fish have increasingly faced an obstacle course of dams, pumps, and dewatered rivers and creekbeds.

Central Valley Chinook salmon populations include four runs-winter, spring, fall, and late fall-with each spawning not only at different times of the year but in different parts of the watershed. The dawning of the age of dams hit the winter and spring runs the hardest, cutting the fish off from their historic spawning grounds in the upper reaches of the watershed. Both runs are now listed under federal and state Endangered Species Acts.

The fall run, which spawns lower in the watershed, was less impacted by dam construction. In recent decades it has numbered more than 10x all the other runs combined and has been the mainstay of the California coastal salmon fishery. Now, even it appears to be in serious trouble: The count of 90,000 salmon this year was the second lowest on record and well below the minimum conservation target of 122,000 set by the Pacific Fishery Management Council. Also alarming is that the number of 2-year-old "jacks" returning was just 2,000, down from a typical count of 40,000. Since most spawners are 3-year-olds, these early returners are considered a good predictor of the size of next year's run.

Ocean conditions are one factor in the salmon decline, with rising water temperatures and more unpredictable upwellings-possibly resulting from global warming. But scientists are also pointing to overexploitation of our rivers and Delta-the "highway" for migrating salmon. The abrupt decline in the salmon population comes concurrently with the collapse of other fish species dependent on the Delta ecosystem, including delta smelt and longfin smelt. The salmon returning to spawn this year would have been juveniles headed to the ocean in 2005, the year Delta water exports hit a record high.

Between unfriendly ocean conditions and the degraded condition of the watershed, the salmon are facing a double whammy. But, as Bay Institute Senior Scientist Tina Swanson points out, "Apart from rolling back global warming, we can't really control ocean conditions. What we can do is drastically improve conditions within the watershed so that more adults can spawn successfully and more juveniles survive the journey to the ocean."

Ann Dickinson is Communications Manager for The Bay Institute (www.bay.org), a nonprofit research, education, and advocacy organization dedicated to protecting and restoring San Francisco Bay and its watershed, "from the Sierra to the sea."

For The Bay Institute, this year's Wild & Scenic Film Festival was particularly exciting because it included the first public screening of "Taking Root," a film-in-progress about our STRAW (Students and Teachers Restoring a Watershed) Project. I recently talked to David Donnenfield, who is co-producing the film with Kevin White (Kevin also has two films in this year's Ocean Film Festival: Restoring Balance: Removing the Black Rat from Anacapa Island and Returning Home: Bringing the Common Murre back to Devil's Slide Rock.) I asked David how the two came to be making a movie about kids working to save an endangered freshwater shrimp.

Taking Root is part of a larger project entitled How on Earth, which began with the goal to survey the spectrum of restoration work happening across the country. David and Kevin wanted to look at projects large and small, in different regions and involving different constituencies and different issues. They also were interested in documenting projects initiated by kids-one of the things that drew them to our STRAW Project, founded in 1992 by a class of fourth-graders.

David attended film school at UCLA (after he "got the bug" while starring in a high school film), but says he was always more interested in social issues than theatrical production. As to why he finds the topic of environmental restoration of particular interest, David points to the late environmentalist David Brower's 3-part concept of "Global CPR"– Conservation, Preservation, and Restoration. While we've all heard about conservation and preservation, David notes, "We felt that very little of the story of restoration had been told." That's a critical oversight, since "in the face of worldwide environmental decline, there is less and less to preserve but more to restore."

In talking about their process for making films, David explains that they do a lot of research up front to understand the issues, the players, and how the story fits into the "big picture." But there is also that sense of "serendipity and discovery" when they actually get out into the field, and that's a large part of what they bring back to the editing room.

And, in fact, editing is the next big challenge for Taking Root. Production on the full-length film (which will run about 1/2 hour) is nearly complete, but David and Kevin are still raising funds to complete the editing. Meanwhile, folks around our office are already looking forward to next year's Wild & Scenic Film Festival, where we hope to be nibbling organic popcorn and cheering the completed film's premiere.

Ann Dickinson is Communications Manager for The Bay Institute (www.bay.org), a nonprofit research, education, and advocacy organization dedicated to protecting and restoring San Francisco Bay and its watershed, "from the Sierra to the sea."