Fish in the Bay – April 2025: WRMP – Eden Landing Trawls.

The UC Davis OGFL lab was contracted by the Wetlands Regional Monitoring Program (WRMP) to perform fish monitoring surveys at four new locations around San Francisco Bay. 

This report covers the first WRMP survey conducted at the Eden Landing Ecological Reserve on April 8^th.

Background.

• Eden Landing Ecological Reserve. Much of the Eden Landing area was restored to tidal flows by 2011.
  • https://wildlife.ca.gov/Lands/Places-to-Visit/Eden-Landing-ER
  • https://www.southbayrestoration.org/pond-complexes/eden-landing
  • https://en.wikipedia.org/wiki/Eden_Landing_Ecological_Reserve
• The WRMP provides coordinated regional monitoring of wetland restoration projects around the SF Bay area. “The WRMP is co-administered by the San Francisco Estuary Partnership (SFEP) and the San Francisco Estuary Institute (SFEI).” https://www.wrmp.org/
• Maven’s Notebook. https://mavensnotebook.com/2025/01/23/notebook-feature-quantum-leap-in-collecting-and-unifying-regional-metrics-on-wetland-health/  “At the end of the first two years of WRMP monitoring, Levi Lewis hopes to have enough data to do a regional comparison and begin to parse how marshes across the Bay differ in species abundance and diversity, and how those map onto environmental quality.”
• Baylands Habitat Map provided by SFEI.
  Described here: https://www.sfei.org/projects/baylands-habitat-map-2020,
  and here: https://www.ecoatlas.org/regions/ecoregion/statewide?bhm=1

WRMP trawls are conducted using the same otter trawling equipment and protocols as has been used in LSB for years, with only one exception: 5-minute trawls for WRMP versus 10-minute trawls for regular LSB monitoring.

Trawls were conducted at seven stations at Eden Landing:

• OAL1 & OAL2: Old Alameda Creek.
• OAR1, OAR2, & OAR3: Old Alameda Restored area.
• MEC3: Mount Eden Creek (to the north)
• WTS: Whale’s Tail South

Eden Landing – First Impression.  Marsh vegetation does not grow tall here.  Most of the Bayside areas are dominated by pickleweed.  The vegetation is a little more mixed farther inland, but the taller bulrushes that characterize upstream marshes in LSB are completely absent.

Short vegetation immediately tells us that salinity is higher.  According to an old saying: “Freshwater makes the marsh grow taller.”  This is because taller freshwater plants quickly dominate over stubby salt-adapted species if the water is fresh enough. 

• Water quality sensors confirmed that salinity at all Eden Landing stations was nearly uniform at 20 to 21 ppt. Higher salinity affects all the critters that live in these marshes.      

1. Familiar Fishes.

Only one each Striped Bass and California Halibut were caught at stations OAR1 and OAL2 respectively.  Thus, we can confirm that both species are present in Eden Landing Reserve but little else.  The Striped Bass catch was accompanied by excellent Striped Bass and Halibut food, in the form of nearly three dozen young Herring! 

Pacific Herring count = 34.  All Herring were very young recruits from the 2025 Herring spawn (30 to 40 mm in length). 

• 33 of the 24 young Herring were caught way upstream in the restored area at station OAR1.
• It is likely that adult Herring spawned here,  These youngsters may have hatched within this restoration area.  

Shiner Surfperch count = 16.  At least 6 heavily pregnant Shiners were caught at stations OAL2, OAR2, & OAR3.  In addition, nine (9) newborn Shiners were caught at station OAR2. 

• The newborns at OAR2 were fresh ‘out of the oven’ so to speak. These newborns were no more than hours old!!!   (Surfperches are live-bearing fishes.  They don’t lay eggs.)
• Old Alameda Creek and the adjacent restored marsh is a Shiner birthing place!

Yellowfin Goby count = 5.  Four out of five Yellowfins were large adults at 110+ mm in length.  The seven “Unidentified/Larval gobies” were likely baby Yellowfins as well. 

Cheekspot Goby / Arrow Goby count = 22 / 6.  Both tiny native gobies were present everywhere except at the far upstream station OAR1.  Arrows were caught only at stations OAL1 (2 Arrows) and MEC3 (4 Arrows).   

Staghorn Sculpin count = 86.  We caught a lot of Staghorns at Eden Landing! 

• Not coincidentally, Staghorn Sculpin numbers in LSB also suddenly surged – from 39 in March to 484 in April. – Staghorns are reliable indicators of El Nino (few Staghorns) versus La Nina (abundant Staghorns) conditions.
• Staghorn Sculpins in SF Bay are extremely sensitive to Sea Surface Temperatures (SSTs) measured at the equator.  How can this be? https://www.youtube.com/watch?v=ZSSW3YNgzNQ

Chameleon Goby count = 38.  Eden Landing is a refuge for Chameleon Gobies!  We found more Chameleons here, and they were larger and more healthy-looking than those we see in LSB.  Chameleons don’t tolerate salinity below roughly 20 ppt.  Lower and variable salinity in LSB makes them look pale and sickly.

• These non-native gobies have been in SF Bay since the 1960s.  https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=717 
• Like their close relative, the Shimofuri Goby, Chameleons change body color at will. Body colors vary from light tan with dark stripes (“Watermelon), to a darker mottled pattern (“Snakeskin”). Males during mating season are widely reported to turn very dark, almost black, when attracting females and defending mating burrows. Plus, males express bright colors at the bases the anal fin and each pectoral fin. (“Dark & Colorful males”).
• Pierfishing-com, Chameleon Goby. https://www.pierfishing.com/chameleon-goby/#google_vignette

The goby shown above was one of the “Dark & Colorful males” shown in the first set of photos.  He lighted up to “Snakeskin” pattern before we were able to take a closer look.

• Based on these limited observations, we conclude that Chameleons are the most beautiful gobies in SF Bay.
  Eden Landing wins the goby beauty contest by a wide margin.

2. Sharks & Rays.

Leopard Shark count = 3.  One youngish adult female and two babies were caught.  The smallest baby boy shark was only 168 mm / 6.6 inches.  He was a newborn! 

• Eden Landing is a Leopard Shark birthing place!

Bat Ray count = 9.  We caught a total of nine adult or baby Bat Rays spread out over six out of seven stations. 

• Eden Landing Ecological Reserve is also a Bat Ray nursery!

Sami with young male Bat Ray, 550 mm, at station WTS.

3. Bottom Critters.  (Fish can swim away.  Bottom Critters tell the whole story!)

Zostera, a.k.a. Eelgrass.  We netted fragments of Eelgrass at MEC3 and OAL stations.  (We never see this kind of “Submerged Aquatic Vegetation” (SAV) in LSB.  Most likely, low and variable salinity makes LSB inhospitable to this highly desirable aquatic plant.)

• Wikipedia: Zostera. https://en.wikipedia.org/wiki/Zostera  
  • The Seri language has many words related to eelgrass and eelgrass-harvesting. The month of April is called xnoois ihaat iizax, literally “the month when the eelgrass seed is mature”.
  • On the Danish island of Laeso … Roofs of eelgrass are said to be heavy, but also much longer-lasting and easier to thatch and maintain than roofs done with more conventional thatching material. 

Musculista Mussel count = 21.  Musculista (Asian Date Mussels) were picked up at stations OAL1, OAL2, and WTS.  This is not good.  Non-native Musculista are notorious disruptors of bottom ecology.  They use their byssal threads to consolidate the muddy bottom into a semi-solid surface that can smother eelgrass beds.  We will keep an eye on this Musculista situation.

Mytilus Mussel.  New Creature!  Nikko immediately recognized this edible bivalve. The rest of us had never seen one before – except on a dinner plate. (Mytilus mussels are probably attached to docks in LSB, but we never pull them up in otter trawls.) 

• Mussels of the Mytilus family form dense shellfish beds on seacoasts around the world.
  The mussel shown above is either Mytilus edulis, (a.k.a. “the Blue Mussel,” or “Common Mussel,”) or Mytilus californianus. We need a mussel expert to make a determination.       
• Blue Mussel, a.k.a. Mytilus edulis: https://en.wikipedia.org/wiki/Blue_mussel 
• California Mussels according to the watersheproject-org: https://thewatershedproject.org/whats-in-your-watershed-california-mussels/
• WARNING! Do not eat mussels in SF Bay!  They can contain algal toxins: 
  Peacock et al (2018) https://www.sciencedirect.com/science/article/pii/S1568988318300258 “Here, this study documents co-occurrence of all four toxin suites in the marine mussel Mytilus californianus during 100-day deployments in 2012 and 2014.”

California Horn Snail.  Rare Creature!  This Horn Snail appeared to be alive!  A “crush test” would have confirmed … None of us aboard were capable of committing such sacrilege.  The snail was released after close examination.

• Native California Horn Snails used to cover the muddy shores of San Francisco Bay. They have been replaced by Eastern Mud Snails over the last century.  They are virtually non-existent in LSB – aside from a small Horn Snail refuge in a mudflat near Palo Alto.   https://www.ogfishlab.com/2023/11/14/fish-in-the-bay-november-2023-part-3-bat-rays-to-the-rescue/    

Mud Tubes.  We encountered many mud tubes in the muddy bottom at station OAR3.  The tubes were about the size and shape of goose poops.  We broke apart several mud tubes in an effort to find an organism.  None were found.  What is this new creature?  

• Myxicola infundibulum? “This sabellid polychaete worm inhabits San Francisco Bay harbors and muddy bottoms, secreting a transparent gelatinous tube of mucous in which it lives.  …  Offshore in bentic communities, the mucous tubes are vertically embedded in soft mud.  Often, our mud grab collects only sections of the soft tubes with no animals inside.  This initially puzzled our biologists as they tried to identify the sources of the tubes.”  https://research.calacademy.org/research/izg/SFBay2K/sabellidworm.htm 
• Sabaco elongatus? “… a marine tube-dwelling polychaete commonly known as the elongated bamboo worm.  It is native to the Western Atlantic … It is a head-down deposit feeder, living in a vertical tube composed of mud, sand, and clay …”  https://invasions.si.edu/nemesis/calnemo/species_summary/67519 

Oregon Mud Crab count = 2. (a.k.a: Hemigrapsus oregonensis).  Native Oregon Mud Crabs may prefer higher salinity here.  https://en.wikipedia.org/wiki/Hemigrapsus_oregonensis 

• Oregon Department of Fish and Wildlife Crab Identificajtion guide: https://www.dfw.state.or.us/mrp/shellfish/crab/crab_id.asp

Atlantic Oyster Drill count = 41.  Non-native Oyster Drills appear to do very well at Eden Landing.  We caught specimens at every station. 

Palaemon Shrimp count = 576.  Palaemon comprised the overwhelming majority of shrimp at Eden Landing.  Native Crangon shrimp were relatively rare, and non-native Exopalaemon (the freshwater shrimp) were absent. 

Corbula Clam count = 78.  Unfortunately, the non-native clams were collected at every station.  The numbers were not huge, and the clams were relatively small and young looking.  Reproductive adults are likely bedded somewhere farther upstream.

Philine Bubble Snail count = 2.  Philine were only seen at station MEC3.
Bad News: Philine are non-native mollusk predators. 
Good News: Philine are documented Corbula eaters.

Anemone count = 39.  We presume that these tiny orange anemones are Diadumene franciscana.  They are widespread in the Bay, but their origin remains unknown. 

• These anemones flourish in higher salinity, above ~ 20 ppt. Anemones collected at Eden Landing were noticeably larger (~1.5 cm) and more brightly colored than those caught in LSB.
• Lower salinity in LSB kills them. In comparable April trawls of LSB, we caught only 36 anemones at station LSB1, and none anywhere else.   
• Diadumene franciscana (San Francisco Anemone). “Like other anemones, it feeds by trapping zooplankton and small epibenthic animals with its tentacles. No impacts have been reported for this species.” https://invasions.si.edu/nemesis/species_summary/52755 

4. Water Color Assessment.

Water Colors.  We kept our eyes on water color.  The normal range from greenish to brownish varies with tides and phases of the Moon.  Occasional explosions of certain dinoflagellate or raphidophyte organisms can turn the water red-brown.   A red tide would be very bad! 

New marshes!  New creatures!

Led Zeppelin, Kashmir.  https://www.youtube.com/watch?v=9vbeilE0UrQ

“My Shangri-La beneath the summer moon, I will return again.
Sure as the dust that blows high in June, when movin’ through Kashmir. …”