How Healthy is the Morro Bay National Estuary?

by Jack McCurdy

That was the dominant theme and question posed at the triannual State of the Bay conference held on May 14-15 in Morro Bay. The answer: it depends on what measure is used.

But there seems to be clear agreement on one thing: the Estuary "faces significant challenges to its health." And "ongoing efforts to protect and restore the Estuary are critical to its continued health," the Morro Bay National Estuary Program (NEP), which conducted the conference, emphasized. And most important, individual and collective action by residents and visitors will decide if the Estuary and its health survives. It is human abuse that has caused the its feeder creeks and the Estuary to deteriorate over the past 80 years.

What Can Be Done?

The biggest threats to the Estuary include the continuing flow of soil and debris down Chorro and Los Osos creeks. The creeks cause sedimentation to fill up the Estuary along with bacteria and chemicals that are harmful to aquatic life and humans alike. There are even what is called "a new category of pollutants known as emerging contaminants" that represents added concern.

These are "chemicals, pharmaceutical,s and personal care products" that apparently are being used in greater amounts and are finding their way into the creeks and the Estuary at a higher rate.

And yet, in seeming contradiction, the amount of dissolved oxygen, which fish and other sea creatures breathe to survive, is still "good" in all parts of the Estuary, except at Baywood Pier and just east of there, as of the last samplings in 2008.

 The NEP's State of the Bay conference in the Community Center was attended by an estimated 50 persons on Friday afternoon, May 14, and about 30 on the morning of Saturday, May 15. (The NEP is an independent, nonprofit organization that was formed after Morro Bay was declared a National Estuary in 1995. It receives most of its funding from the U.S. Environmental Protection agency. Its office is at 601 Embarcadero, Suite 11, Morro Bay.)

Its report to the conference, titled "Estuary Tidings," concluded that conditions in the bay are "mostly stable." That means overall, but not consistently among the eight indicators that the NEP used to gauge the health, which were framed as questions:

       1. Is the bay clean enough for support of commercial shellfish farming?

Yes, there are three "farms." But two are closed  to harvesting "due to historically elevated bacteria levels or due to a lack of water quality data."

The California Department of Public Health, which inspects the farms to assure that they meet regulatory standards for clean water, has found that the water is clean enough in three areas in the central part of the Estuary. "Waters are regularly monitored for fecal coliform, whose presence indicates that fecal contamination may have occurred," the NEP report said. "Since bivalve shellfish are filter feeders, pollutants in the water can become temporarily concentrated in shellfish and cause illness in humans who eat them."

2. Is Morro Bay safe for swimming? Yes, in most areas.

Are creeks safe for recreational contact? Not consistently.

"Most of the bay sites monitored for bacteria showed levels safe for swimming. However, at some sites in the back bay, bacteria levels were above the recommended threshold in 10% to 20% of samples collected. The majority of creek sites posed a safety risk in at least 20% of samples collected." "Bacteria, viruses and protozoa can cause illness in humans, who may ingest water while swimming." This could hold true for those kayaking or boating as well, if they come in contact with the water, the NEP said.

3. Does water quality levels in creeks and the bay support fish and aquatic life?

 Yes, habitats are healthy in most areas, but some are degrading.

The NEP monitors the habitat quality of the creeks each spring, and these data are compiled into a scoring system that indicates the health of the riparian ecosystem.

This monitoring detected the "emerging contaminants" but showed good dissolved oxygen levels at five of seven locations in the Estuary. One of the emerging contaminants is called "nonylphenol," a chemical used in many common products and is under study by the San Luis Obispo Science and Ecosystem Alliance (SLOSEA). It has been identified in "significant concentrations" in water and sediment samples from the Estuary and in goby fish there.

4. Does Morro Bay support healthy eelgrass beds?

Yes, after declines in the 1990s, eelgrass acreage has shown continued recovery.

Eelgrass is an underwater plant that represents an important habitat and source of food and shelter for many fish and invertebrates as well as wintering black grant geese. It is recognized as "a good indicator of ecosystem health because it is sensitive to poor water quality."  The acreage of eelgrass in the Estuary has changed significantly over the past 50 years and took a dive after the 1994 fire along Highway 41 east of Morro Bay. It burned a large area of the Estuary's watershed, and, coupled with subsequent El Nino rainstorms, resulted in major erosion, causing sediment to bury some eelgrass beds and a severe decline in eelgrass acreage. Since 1997, there has been a steady recovery in eelgrass beds up to more than 80% of what it was before the fire.

5. Are important habitats being protected, enhanced and restored?

Yes, over 3,000 acres of habitat have been protected and over 400 acres have been restored or enhanced.

The Estuary and watershed are comprised of many diverse habitats that are critical to the survival of native plants and animals, including some species found nowhere else in the world. Healthy, intact habitat also protects water quality in feeder creeks and the Estuary.
Habitat loss and degradation occurs through poorly-planned development, poor land management, invasive exotic species and pollution. The NEP has employed these strategies in partnership with other groups to counter these threats:

—Conservation agreements with landowners upstream from the Estuary to protect land from development and preserve traditional uses such as farming
—Land acquisitions to protect rare habitat, endangered species and water quality. More than 1,100 acres have been purchased in the watershed since 1995.
—Restoration projects to restore ecosystems altered or destroyed by human activity. Such a project was completed in 2008 by the NEP and its partners on Walters Creek, which had been blocked by the U.S. military in the 1940s. The original flow and natural vegetation was returned to the Creek    .
—Enhancement projects in cooperation with landowners to remove invasive species, install riparian fencing or reduce groundwater extraction to increase stream flow, which are designed to deter bacteria and pathogens flowing into creeks and eventually the Estuary.

6. Is the Estuary filling in at an unnatural rate?

Yes, sedimentation of the Estuary has been accelerated by man-made disturbances within the watershed.

Estuaries gradually fill as part of a natural geologic process, but this process has been accelerated as much as 10 times the natural rate for the Estuary. One study indicates that the source of 50% of current marsh sediment is from human disturbance within the watershed. The Estuary is receiving more sediment from the watershed, and that buildup is complicated by reduced tidal flushing caused by the construction of the causeway and jetty at the harbor entrance during World War II. This rise in the elevation of tidal and sub-tidal flats is converting the shallow waters and eelgrass beds to mudlfats and marshes—all of which could result in a shift away from a marine-estuarine habitat to a salt marsh wetland-freshwater riparian habitat.

Preventing or limiting erosion in the watershed is the first step in slowing sedimentation of the Estuary, and the most cost effective way is implementing best land management practices through such measures as soil conservation by installing livestock fencing to minimize access to creek banks, which allows deep-rooted plant communities to thrive and curb the erosion that results in sedimentation.        

7. Are the bird populations that depend on Estuary habitat stable?

Yes, most populations appear stable over the last 15 years, although brant and snowy plovers require continued monitoring.

Bird populations have declined everywhere over the past 100 years. The Estuary is home for more than 200 species of birds and an important stop on birds' Pacific Flyway. Data in the Estuary Tidings show a fluctuating number of shorebirds in and around the Estuary, but the last counts since 2005 are higher than those between 1988 and 1991. However, the the number of brant geese in the Estuary and throughout California has declined significantly over the past 10 years, which reflects a loss of habitat, the report said, and has resulted in the California Department of Fish and Game listing it as a species of special concern.

The population of the snowy plover, which nests on beaches, declined sharply around the Estuary between 2004 and 2008 (the most recent year with data) and has been protected under the Endangered Species Act since 1993. Special fencing was installed by Fish and Game starting in 2002 on the sandspit to protect plovers during their nesting season.

8. Does the Estuary and watershed support a healthy population of steelhead trout?

No, viable steelhead habitat exists, but persistent problems contribute to population decline.

Steelhead populations have decreased on the Central Coast and within the Estuary's watershed, mostly in streams flowing into Chorro Creek,  resulting in it being designated as a threatened species. Declining water habitat, and the loss of cold water, food and protection from predators, are the main reasons. The loss of water results primarily from wells that reduce stream flows, restriction of creeks by roads and dams, erosion into creek beds from developments and invasive plants and aquatic species.