Lake Merritt Institute Aims to Prevent Another Fish-Kill

by Sarah Van Roo

Beautiful Lake Merritt was front and center again after our series of January atmospheric rivers. Following a summer of red tide drama and an enormous fish die-off, now we can add flood danger to the list of Mother Nature’s unexpected lake-related events. Now, we hopefully watch for our usual bird migrations, markedly reduced this year because of the lack of fish. Fortunately, the Lake Merritt Institute is leading the charge on addressing the causes of and solutions to these recent events.  

A population explosion of microscopic algae called Heterosigma akashiwo caused the summer fish die-off in Lake Merritt and throughout the Bay, an event more severe than any seen in decades. Alarmingly, cysts of the algae remain at the bottom of the lake, awaiting the next perfect set of circumstances—high temperatures, algae blooms causing low oxygen, excess nitrogen, and phosphorus—until, again, we see the devastation of marine life.

The Lake Merritt Institute (LMI) monitors the lake and is probably the best source of ongoing information about the jewel of Oakland. With more than 120 members, it is a community-based, non-profit corporation that works cooperatively with volunteers and the City of Oakland. After the red tide crisis abated, LMI Membership Committee suspected that Oaklanders who live by and love the Lake would be looking for ways to help with and to respond to this environmental crisis right in our neighborhood. 

LMI responded by resuming its information table at the Saturday Lake Merritt Farmers Market. Susan Campidicio, the volunteer liaison to the institute’s board, was one of the volunteers staffing the LMI table at the Farmers’ Market during and after the red tide.

 “Mostly we just needed to listen,” she said. “People were in shock, very emotional, describing seeing dead stingrays, huge bass, and literally piles of dead fish everywhere. People wanted to talk about how we could stop it from happening again.”

“There was a huge interest in this amazing process,” Campidicio reported. “It was a teachable moment. They just needed to talk about the effect on their souls, that it was so devastating.”  She continues to staff a table that will be at the farmers market monthly, and she hopes to establish another one at the amphitheater when she gets enough volunteers. The table recruits new volunteers and members and educates those who enjoy Lake Merritt. 

From a second-floor office in the Sail Boat House on Lake Merritt, the Institute is led by a board of directors and Executive Director James Robinson. The Institute contracts with the city, organizes vibrant volunteer groups, applies for related grants, teaches classes, and promotes mechanical harvesting as a replacement to herbicide use. Its current focus is developing methods of aerating the lake to bring in much-needed oxygen for aquatic and marine health. A staggering 6000 pounds of trash is removed from the lake monthly through their efforts.

Dr. Richard Bailey founded the LMI in 1992 “because of all the potential to enhance the lake, and to strengthen the relationship between it and the people who love it.“ His background in environmental science and years of government and private sector experience led to involvement with the lake, and to an epiphany one day while he was out on a boat and saw the many opportunities and potential to enhance the lake.  

“When the consulting company I worked for laid me off, I wrote a grant application to create an improvement plan,” he said. “It was funded, but the money went to the City, which put it out to bid. I won the bid to write the plan, which included creating the Lake Merritt Institute to implement plan projects. Thus, LMI was born, and it  has accomplished some of the planned projects, with more to come. We have evolved into a go-to source of information about the lake,” he said. Lake Merritt Institute has been under contract with the city of Oakland to remove trash from the lake since 1996. 

You may have seen LMI’s four “U-Clean-It” stations around the lake. They supply tools for volunteers to clean the lake and pick up trash.  LMI has also pushed for storm drain filters and installed bulletin boards and tide gauges. Total trash collected in 2022 by LMI volunteers added up to 54,895 gallons! 

Lake Merritt is a tidal estuary, an arm of the Bay. From the Oakland Estuary channel, the water is flow-modified into the lake through carefully monitored locks designed to keep the lake level manageable. The lake was originally mudflats and wetlands, a treasured hunting ground for local Ohlone and others, via watershed creeks and rainwater run- off from the hills.  Today, no sewers empty into the lake.  Approximately 2,000 acres of very urbanized watershed drains into Lake Merritt via Glen Echo Creek, which enters the Lake at Grand Avenue and Harrison Streets and through the Sausal Creek watershed. Just before the outfall to the Lake, the Glen Echo Creek flows through a concrete channel adjacent to the Veterans Memorial building. Overall, about 4,600 watershed acres drain into the lake. 

Oakland’s first mayor, Samuel Merritt, famously decided in 1870 that there was too much loud gun hunting around his home. He had the 160-acre area declared the nation’s first wildlife refuge, a status it maintains today. It provides sanctuary for the hundreds of migratory birds we usually see this time of the year. The bird islands were added in the early 1920s. A boom cordons off part of the lake and islands from boating activity to protect the birds.  The lake has been dredged periodically over the decades to remove toxic substances that sink to the bottom. Migrating birds’ excrement paradoxically creates some of this problem. 

As decades of shoreline construction unfolded, the reduction of the remaining oxygenating mudflats meant little mud surface was exposed to the air, resulting in pockets of salty, dense bay water. These pockets diminish oxygen through the bacterial decay of organic matter. A donor and the City of Oakland, working with the Institute, installed and maintain two aeration fountains, providing  much-needed oxygen to the water and an aesthetic enhancement to the lake. A tidal estuary between the lake and Laney College also helps but has become populated with encampments in recent years, adding to the problems. The two fountains have helped, but not enough.

During last summer’s red tide, it became clear that oxygen depletion was the culprit. The most dramatic week saw 20,000 dead fish pulled out of the lake, and huge dead sea bass rotting on the lake floor. It was an event that pulled people together, standing stunned on the shores, looking at the power of nature, and yearning for long-term solutions as they watched fish rising to the surface gasping for air.

Our recent Spring storms have also compromised the health of the lake. The freshwater runoff from the storms created a separate layer on top of the salty (and heavier) bottom layer of tidal water, and the layers do not mix. Called “stratification”, the top fresh water layer acts as a barrier to oxygen in the air getting to the lower salt layer. LMI is engaged on this issue, Bailey said.

The Institute worked with the Rotary Nature Center and local naturalist Damon Tighe to collect data during the crisis last summer. Damon worked with the app iNaturalist, and swiftly collected citizen science data from all around the Bay and Delta—moving much more quickly than most government entities. His findings were posted on Facebook daily, engaging many others in the process. The Rotary Nature Center held numerous real-time education workshops with LMI as the red tide washed on.  While there are still a lot of unknowns, multiple agencies are involved in looking for answers.

The California Indian Environmental Alliance (CIEA) purchased an aeration fountain for the Clean Lake Program during this crisis period. Oxygen remains a critical issue, and LMI is fundraising toward a $1 million goal to install a more sustainable solution for aeration.

Recently LMI has led the charge for gathering more information about dissolved oxygen in the lake and technology solutions for anticipating and responding to harmful algal blooms.

“Few people are aware of how hard LMI works to remove trash from the shores of the lake and pull heavy items that are sometimes just dumped,” LMI board member Katie Noonan said. “There is good fellowship in this community effort to take care of our common home here in the heart of urban Oakland.” Noonan has been a LMI board member since 2017 and also co-chairs the Rotary Nature Center Friends, which partners with LMI to provide student learning opportunities. The recent fish die-off was a chance for an immediate educational response, and LMI and Rotary Nature Center jumped in together to take advantage of the teachable moment.

Fast action by Oakland’s Stormwater Manager, who called into service the summer algae harvesting machine, removed the rotting fish near pedestrian pathways and shorelines, but we are left with questions:

  • What caused the toxic bloom and the fish kill? (High temperatures, nutrients, and lack of oxygen.)
  • Will this happen again, and can we prevent it? (Yes, and yes; an aeration system can help prevent fish kills.)
  • How could we respond to another harmful algal bloom to lessen the severity of the kill?
  • What will be the long-term effects of the fish kill on estuary ecology: migratory birds, fish, and humans? As our spring migration season unfolds, there is a noticeable dearth of the usual bird flocks. The diminished diversity of the avian population has been striking. 

LMI has subscribed to the services of the company LakeTech to assist in monitoring the quality of the water in the lake. This will include four buoys to measure temperature, dissolved oxygen, salinity at the top and bottom, and will measure turbidity and chlorophyll-a, as well as the level of the lake.  LakeTech will monitor, clean, and calibrate the buoys. help predict and measure the health of the lake water. Discussion of an alternate aeration system is still under way, so the information gathered from these buoys will be helpful. Dr. Bailey is also currently pursuing grant funding. 

New LMI Board member Josiah Albertsen has lived on Lake Merritt for about six years. Originally inspired by seeing volunteers working around the lake, he brings refined professional tech skills that he hopes to harness to improve the lake. His immediate focus is the aeration system that the lake needs to improve its oxygen, and therefore its marine and aquatic health. “We have all seen the two fountains in the lake, one of which stopped working during the red tide. The science says we need four fountains as an immediate solution,” Josiah said, “and a larger lake-wide system is the long game.” The larger system could cost over $1 million. Josiah helped LMI start a-go-fund me to raise money toward the new fountains, and the longer- term goals.  So far it has raised about $6,500 in small donations.  A campaign involving businesses and large lake residences will unfold soon. Donate now at:

“This is a man-managed lake that is actually an estuary of the Bay”, he said.  “Most people take for granted that it has always been a lake, but it is a unique set of circumstances that it even exists, considering its natural state would be mud flats.” 

The time for taking the lake for granted as just a photo op has come to an end.

More about LakeTech’s proposals: Helping Lake Merritt Estuary solve its problems-ek.pdf

Lake Merritt Institute for info on the institute.

Lake Merritt resident Sarah Van Roo is a retired attorney, journalist and photographer. She also tends the Bee Hotel Garden at the Gardens at Lake Merritt and manages social media for the gardens, including for the very successful annual Autumn Lights Festival. For the Splash Pad News, she previously authored articles about the Monarch Butterfly migration in Oakland, the Autumn Lights Festival and a profile of Mary Jo Sutton, head of the Splash Pad Park Native Garden team. She reported on the total facelift that transformed the entrance to the Gardens at Lake Merritt. Articles about the Lake Merritt Institute and the Weed Warriors appeared March 2023.




8 responses to “Lake Merritt Institute Aims to Prevent Another Fish-Kill”

  1. Bruce Cobbledick Avatar
    Bruce Cobbledick

    Great article, lots of information, thank you Sarah.

  2. Sarah: Thanks for a great article. You get an A.

    It would be A+ but for the mention that some sewers empty into the Lake. Although there may be sewage entering storm drains during extreme rainfall, there are no direct sewer outlets to the Lake.

    Keep up the good work. We need everybody on board to fight harmful algal blooms and the depleted oxygen conditions that they cause.

    Dick Bailey,
    Founder, The Lake Merritt Institute

    1. Sarah Van Roo Avatar
      Sarah Van Roo

      Thank you Dick, I will make that correction. I appreciate your comments.

  3. Mary Bader Avatar
    Mary Bader

    What an interesting, informative article about multiple aspects of Lake Merritt ecology and community.

  4. Elizabeth Hasley Avatar
    Elizabeth Hasley

    Thank you Sarah, for all you do and doing it so well.
    Elizabeth Hasley

    1. Sarah Van Roo Avatar
      Sarah Van Roo

      Thanks so much!

  5. Myra Redman Avatar
    Myra Redman

    Although I have been a member of LMI for years, I learned a lot from this article. Well researched and so clearly presented. Thanks!

  6. Wow, great article. Thank you!