Friends of Gualala River

by Peter Baye

published in the July & September, 2017 issues of The Calypso, newsletter of the
Dorothy King Young Chapter of the California Native Plant Society
reprinted with permission

Part 1 – Wigeongrass and Sago pondweed

Last April (2017), our local public radio station (KZYX) ran an excellent “Ecology Hour” program interviewing world-renowned oceanographer John Largier from University of California, Davis Bodega Marine Lab. Marginal to the discussion of the physical processes that influence the Mendocino Coast river estuaries was a reference by some callers and hosts, to “algae” in the river.

That was an unintended cue for this botanical gem column on the trio of native submerged aquatic vascular plants that variably dominate our estuarine rivers. They are not algae themselves, but can become covered by algae at some stages, and at a distance, are mistakenly identified as nuisance algal blooms. Nothing could be farther from the truth, since native submerged aquatic vegetation (SAV) beds are the standard of high estuarine habitat quality sought all over the world – qualifying as both ecological and botanical gems. But aquatic plants species, especially submersed species that complete their life-cycles under water, are also out of sight and thus out of mind for many observers. They are thus easily mistaken, by prejudice, for algae when visible at the water surface. That prejudice can lead to misguided demands for getting rid of falsely perceived “nuisance” algae.

So before we have to defend our pristine native SAV beds, let’s introduce two of a trio of revered dominant underwater plant species that cohabit Mendocino Coast river estuaries: wigeongrass, Ruppia cirrhosa and sago pondweed, Stuckenia pectinata (syn. Potamogeton pectinatus). The linear-leaved eelgrass, Zostera marina is the third species and it will be discussed in the Sept-Oct, 2017 issue of the Calypso. [below] Thick beds of wigeongrass, Ruppia cirrhosa, mantle upstream brackish reaches of the fully tidal Albion River estuary. Long frond- like shoots sway back and forth with each ebb and flood tide. July 1, 2017

WIGEONGRASS, Ruppia cirrhosa, is the most widespread and abundant of Mendocino’s estuarine SAV species: it occurs in every estuary, whether fully tidal or summer lagoon, in DKY’s [Dorothy King Young Chapter of the California Native Plant Society] territory. In some rivers, like Navarro, Albion and Big Rivers, it extends for miles. That fact makes it all the more astonishing that the genus doesn’t even appear in the Mendocino Flora (Smith & Wheeler 1992), and there are no reported herbarium or checklist records of it from Mendocino in the Consortium of California Herbaria or Calflora databases! There isn’t even a record of its close relative (even a synonym in some taxonomic treatments of Ruppia), R. maritima. “Underrepresented” is an understatement for this botanical omission – the estuarine equivalent of omitting redwoods from the Mendocino flora.

Emergent erect spike of Ruppia cirrhosa, on still water of Navarro River lagoon. July 18 2013

Our estuarine riverbed wigeongrass consistently produces long, wiry coiled peduncles, which is the diagnostic characteristic for Ruppia cirrhosa. R. maritima is the typical wigeongrass in salt marsh pools worldwide, which are shallow, warm, and more saline than seawater. Contrary to some descriptions of Ruppia, the male inflorescences of our R. cirrhosa often form erect spikes that emerge above the water surface, and release masses of pollen that make a whitish film on the water that winds can blow into piles of decaying scum in late summer.

Ruppia cirrhosa mats drape over limbs of downed alders as the Navarro River lagoon draws down in summer. July 18, 2013

Wigeongrass is a stealthy plant: when it grows underwater, it is barely detectable. When the fronds reach just below the water surface, they branch and proliferate, and drag on the water surface, heralding themselves by flat water surface areas, outlined by wind-waves and ripples around them where there is no wigeongrass. Finally, the fine linear leafy branches expand into floating mats that completely cover the water surface. Ducks and geese push through the floating mats as they feed on the leaves and invertebrates that live in them, leaving trails. Steelhead jump all around the food-rich wigeongrass canopies at dusk and stickleback move in abundance under the canopies themselves. During heat waves, stickleback fish kills occur when the dense tangled floating mat interior overheats, and stickleback can’t escape in time.

Sandpipers foraging on a thick floating Ruppia cirrhosa mat on the lagoon of Navarro River. August 6, 2016

Wigeongrass grows from perennial rhizomes, but it also colonizes new substrate very rapidly by seed and by vegetative propagules. Unlike eelgrass and sago pondweed, it regularly colonizes gravel estuarine river beds like an annual, apparently from seed. In late summer, it spreads over sandy bottoms near the river mouth by creeping rhizomes and stolons, forming prostrate turf across the bed, which later develops vertical shoots. It even can form unusual short zig-zag lateral branches with pre-formed short anchor roots, which readily detach, disperse and sink to the bed as instant, ready-to-grow vegetative propagules.

Wigeongrass can grow in both seawater and fresh water, and appears to tolerate switching back and forth. The primary production of wigeongrass in our estuaries is huge. So is the density of shoots under the floating mats: a single hand-grab of a tangled shoot mass can be heavier than a person can lift out of the water.

SAGO PONDWEED, Stuckenia pectinata (syn. Potamogeton pectinatus), is another nearly cosmopolitan aquatic plant species. It has less salt tolerance than wigeongrass, usually occurring in freshwater or fresh-brackish water.

Flowering and fruiting spikes on floating mat of sago pondweed, Stuckenia pectinata, Navarro River lagoon (closed nontidal freshwater estuary phase). July 18, 2013

Salinity about half seawater strength (3.5 % salinity, 35 ppt) is enough to severely inhibit its growth or kill it. Sago pondweed has similar fish and estuarine invertebrate food-chain support value as wigeongrass, but it has even more food value for dabbling ducks and diving ducks. The fruits (drupes) and pea-sized, seed-like vegetative propagules it forms in fall (turions; overwintering detached “buds”), as well as its rhizomes, are eagerly consumed by waterfowl. The foliage is also consumed. Sago pondweed colonies in our river estuaries are usually patchy, far less extensive than wigeongrass. But they can also rebound in “boom” years and actually overtop and surprisingly replace dominance by wigeongrass over extensive areas, at least temporarily.

Flowering spikes of Stuckenia pectinata with anthers. July 2013

Wigeongrass can be distinguished from sago pondweed easily when they are flowering or in fruit. Sago pondweed has thick, elastic peduncles terminating in spikes with whorls of flowers or swollen brown, nearly round drupes. Wigeongrass has slender-peduncled inflorescences (wiry and coiled in R. cirrhosa), terminating in 3 or more terminal branchets with asymmetric pointed fruits, or a short spike of whitish male flowers (mostly anthers). Vegetatively, both species have very narrow linear leaves, but wigeongrass has tiny teeth along the blade margins, and long sheaths that pull themselves away from the shoot, at their bases. Sago pondweed sheaths enclose their stems tightly, like a tube with overlapping margins where they enfold the stem. Sago pondweed is far more difficult to distinguish from linear-leaved pondweeds in the genus Potamogeton, in which it was traditionally placed as P. pectinata.

W.L. Jepson was so enamored of sago pondweed as a waterfowl food in early historic Suisun Marsh (San Francisco Estuary) that he wrote a popular article about his first-hand observations for Sunset Magazine, “Where Ducks Dine”, in 1905. (yes, it’s found online!). When canvasback ducks can’t feed on sago, which makes their flesh sweet and nutty, they eat clams that make their meat taste fishy and gamy. Canvasback hunting has lost popularity as sago pondweed wetlands have declined in California.

Fully elongated fruiting spike of Stuckenia pectinata. August 2011

Sago pondweed is reported in the Mendocino County flora from inland ponds, but only one coastal pond complex (Hunter Lagoon and Davis Lake, Manchester) and two estuaries: Pudding Creek (above the dam, however) and Big River. In fact, it is intermittently abundant and extensive at Ten Mile River, near the head of navigation on Albion River, and in the Navarro, Garcia (P’dhau), and Gualala estuaries.

There are basically three types of coastal river estuaries in Mendocino County that predict the location and mix of our native SAV plant species composition. Perennial tidal estuaries, intermediate (choked) tidal estuaries, and seasonal estuaries forming non-tidal summer lagoons.

Perennial fully tidal estuaries include the Albion River and Big River. Their mouths are sheltered from Pacific swell and large coarse-grained barrier beaches by rocky headlands that form quiet embayments, keeping their mouths from closing (by barrier beaches) or choking up with sand. Fully tidal estuarine rivers are home to a gradient of all three species. Ten Mile River estuary is usually tidal all year, but with flows that can become choked and reduced when the barrier beach and shoals grow across the mouth in summer.

Floating, fruiting canopy of Stuckenia pectinata over a bed surrounding the riparian woodland and marsh island above the mouth of Navarro River

The Gualala and Navarro River Estuaries, in contrast, are usually tidal only when river flows force their high coarse-grained barrier beaches to breach and open a tidal inlet. When freshwater flows diminish in spring or summer, the tidal inlets close, and form deep freshwater to fresh-brackish lagoons (saltier at the bottom; “stratified”), with water levels well above high tide. Eelgrass cannot compete or survive in non-tidal brackish to freshwater lagoons, but wigeongrass and sago pondweed can thrive in them, and do.

In all three estuary types, a highly variable mix of wigeongrass and sago pondweed beds occur. They dominate tidal estuaries in their more brackish to freshwater tidal river reaches, overlapping with eelgrass, but dominating above the upstream reach of eelgrass. In non-tidal summer lagoons, wigeongrass and sago pondweed vary greatly in relative abundance and position, with a mix of persistent old perennial beds, and rapid new colonization responding to changed estuary conditions.

The next time you drive over one of the Mendocino County estuaries on Highway 1, and see “algae”, think about running down to the shore and looking for beached samples of one of our native SAV species. And if you overhear discussion of “algal blooms” in our estuaries, help educate about what native vascular plant species lie underneath and attached to those epiphytic algal mats, and what they indicate about environmental health and water quality. This region is an estuarine sanctuary compared with most of the California Coast, and we can boast of some of the most healthy, beautiful and diverse estuarine SAV in the state.

Part 2 – Eelgrass, Zostera marina

Of the three submerged aquatic plants occurring in coastal Mendocino and Sonoma counties, eelgrass, Zostera marina, is a true seagrass that occurs in soft sediments (mud or sand) of fully tidal bays and estuaries with high transparency, allowing light to penetrate to the bottom. Wigeongrass (Ruppia cirrhosa), and sago pondweed (Stuckenia pectinata, syn. Potamogeton pectinatus), the two other estuarine species in our area, were treated in Part 1, July-August, 2017 issue of the Calypso. [above] Zostera marina at low tide, lower Albion River estuary, on rising tide with seawater flooding into the estuary. Unidentified marine algae grow as epiphytes on the blades. July 1, 2017.

It has flat, broad linear grass-like blades on long, supple flexuous shoots that sway with tidal currents. Like all seagrasses (marine flowering plants), it completes its life-cycle in seawater, flowering, fruiting and establishing from seed or clonal (vegetative) growth under water. It can grow in the lower intertidal zone, but it flourishes in shallow subtidal water, especially in cohesive muddy or sandy mud sediments where its rhizomes can anchor. In tidal rivers, it has to be able to tolerate full marine salinity seawater on rising (flood) tides, but also freshwater pulses on low tides in winter when river discharge is high.

The floating canopy of Zostera marina beds a half mile upstream from the mouth of the Albion River, Aug 6, 2014. Little epiphytic algae grows on the blades some drought years

Eelgrass beds provide ecologically important fish habitat: nurseries and foraging (feeding) habitat for small estuarine fish (including anadromous salmon and steelhead) that move through their canopies or feed around their edges, where they have access to visual cover from predators. They also help bind and stabilize sediment and store carbon in sediments. In the Ten Mile estuary, eelgrass canopies are crawling with juvenile Dungeness crabs in spring some years, moving up-estuary on flood tides. Waterfowl, especially brant, consume the shoots.

Zostera marina canopy floating at the water surface, vertical shoots rising in the water column below. Big River July 18, 2012.

In summer, eelgrass leaves develop epiphytic algae: marine or estuarine algae that grow on their leaves. Heavy covering of algae on eelgrass can trigger seasonal decline or even seasonal dieback, especially when temperatures warm in choked, brackish tidal estuaries. Turbid water, due to either suspended mud or algae, also can cause eelgrass decline by reducing light penetration in the water. Eelgrass thrives best in transparent cool, saline water with daily tidal flows and strong tidal circulation.

Zostera marina growing upstream of its usual limits, mixed with Ruppia cirrhosa in brackish tidally choked estuarine conditions, upstream of Hwy 1 bridge, during a major drought with low freshwater river outflows. Aug 14, 2015

Our native estuarine SAV dominant plants are grossly under-documented. It is particularly remarkable that the robust, extensive eelgrass beds of the Albion estuaries have escaped the attention of researchers and our state and federal resource agencies, as well as our floristic database records. There is only one reported Mendocino County locality of the species, Big River, in Calflora and Consortium of California Herbaria. There are no botanical records of the magnificent Albion eelgrass beds, or the highly elastic Ten Mile River eelgrass beds that vary between mile and mere yards long.

Zostera marina colonizes our tidal estuarine river beds upstream during droughts, following seawater mixing – salinity – gradients. A new colony is growing here in an upstream reach under freshwater willow swamp drought year, Ten Mile River, 2013

Eelgrass occurs only in tidal estuary (daily tidal flows) reaches where seawater influence is strong, at least during flood tides that deliver salty, clear water.

There are basically three types of coastal river estuaries in Mendocino County: perennial tidal estuaries, intermediate (choked) tidal estuaries, and seasonal estuaries forming non-tidal summer lagoons. Perennial fully tidal estuaries include the Albion River and Big River. Their mouths are sheltered from Pacific swell and large coarse-grained barrier beaches by rocky headlands that form quiet embayments, keeping their mouths from closing (by barrier beaches) or choking up with sand. Fully tidal estuarine rivers are home to a gradient of all three species.

Zostera marina beds grow in a distinct zone the tidal channel below brackish tidal marsh, Big River. Sept 6, 2014

Eelgrass occurs in these fully tidal estuary (daily tidal flows) reaches where seawater influence is strong, at least during flood tides that deliver salty, clear water. Eelgrass also occurs in our choked, intermediate tidal estuary, Ten Mile River. Ten Mile River estuary is usually tidal all year, but with flows that can become choked and reduced when the barrier beach and shoals grow across the mouth in summer. The Garcia River is also subject to choked tides, but its mobile gravel bed all the way to the mouth seems to exclude stable eelgrass.

This year, unexpectedly, the Navarro River mouth sustained an open tidal inlet through the summer, and changed from its normal freshwater above-tide lagoon condition, to a tidal brackish estuary that could support eelgrass if the unprecedented tidal lagoon condition returns in future summers. Is this unprecedented event a random fluke, or a harbinger of the future? Could eelgrass expand its range in Mendocino County as sea level rises and climate changes? Eelgrass and its associated Mendocino lagoon/estuary aquatic plants should be informative “sentinel” species for climate change here.

All photos by Peter Baye

For more information, see:
Gualala Estuary: Native Aquatic Vegetation versus Algal Blooms

This article is a brief overview.
See all of the articles from the Water Quality campaign.

Historically, the Gualala River was home to abundant coho salmon and steelhead trout populations that numbered in the tens of thousands. Today, the endangered coho salmon are all but gone and threatened steelhead are struggling to survive in the home river they evolved and adapted to over millennia. The dwindling salmonid population is a critical indicator of the declining health of the Gualala River, and its 300 square mile watershed, and continues to be at the core of Friends of Gualala River’s work.

FoGR is working with state agencies to reduce water quality impairments from both sediment pollution and pollution from stormwater run-off containing toxic tire grit (6PPD).

Adult coho salmon; photo by NOAA Fisheries Sediment (TMDL)

In 2001, the U.S. Environmental Protection Agency (EPA) listed the Gualala River as impaired under the Clean Water Act due to excessive sediment and high temperatures – both conditions that hamper fish spawning and create unhealthy conditions for fish throughout their lifespan. The chief sources of sediment are roads, landslides, and legacy timber harvesting practices.

California agencies failed to develop plans to reduce sediment and temperature for 20 years. In 2021, FoGR petitioned the State Water Resources Control Board and North Coast Regional Water Quality Control Board to incorporate the EPA’s Gualala River Total Maximum Daily Load (TMDL) for sediment into the North Coast Basin Plan and to develop and implement an action plan specifying how sediment pollution will be reduced throughout the watershed. That petition was successful. FoGR achieved a major accomplishment that will help improve water quality and reduce sediment pollution in the Gualala River and its tributaries – a pivotal step in assisting salmonid recovery efforts.

Now that FoGR has successfully negotiated an agreement, work can begin in earnest to restore the impaired Gualala River and its tributaries. The Regional Water Board adopted the Action Plan for the Gualala River Sediment TMDL in February, 2026, and is developing a Gualala Roads Assessment Order, a watershed-specific order that will address sediment pollution by requiring the inventory, assessment, and prioritization of sediment-generating roads.

Sediment from the remains of a timber company’s summer crossing sheds into the North Fork during winter flows. (Photo courtesy of FoGR) Stormwater (6PPD)

In 2020 FoGR learned of a chemical found in tire grit that pollutes stormwater and kills a number of different aquatic species. It is especially toxic to coho salmon— 40 parts per trillion in a quart of stormwater kills juvenile coho. Information has been pouring out of the State of Washington where the effects of 6 PPD were first discovered as scientists race to learn more about how the compound kills and what can be done about it.

In 2022, CA Urban Streams Alliance-The Stream Team (The Stream Team) expanded its long-standing watershed monitoring program and began collaborating with Friends of Gualala River (FoGR) to investigate 6PPD-Quinone (6PPD-Q)—a tire-derived pollutant highly toxic to Coho Salmon and Steelhead—in the Gualala River estuary.

In May of 2024 the team of volunteers ran their first samples and discovered that stormwater runoff from the downtown area of Gualala contains high levels of 6PPD-Q, confirming their suspicions. “It makes sense,” says Baker. “Even though Gualala is a small town in a rural area, we have concentrated traffic, especially trucks, trailers, and other heavy vehicles all using Highway 1.”

Storm-event samples were collected at four sites upstream and downstream of major road surfaces and analyzed for 6PPD-Q, zinc, oil and grease, and standard field parameters. Results show elevated 6PPD-Q (up to 170 ng/L), zinc, conductivity, and turbidity, with highest concentrations at sites influenced by Highway 1, gas stations, and parking lots.