Lake Merritt: An “Accidental Zoo” with a Major Mystery

Dr. Jim Carlton

by C. J. Hirschfield – On December 4, International Wildlife Conservation Day, more than 70 people attended the premiere of a new Lakeside Chats series, offered for free by Rotary Nature Center Friends.

The title of the talk was “An Unsolved Mystery: The Enigmatic Beach-Hopper of Lake Merritt,” and the speaker was Dr. Jim Carlton, an internationally renowned expert in invasive marine species whose career began on the shores of Lake Merritt in 1962, when he was a teenager intrigued by a tube worm he found at our urban lake. To help identify his very first find, young Carlton went to the Rotary Nature Center—whose Friends group was sponsoring his presentation and which had reopened in 2018 after being closed for many months.

Carlton is now Professor of Marine Sciences Emeritus at Williams College. He has written six books, and a prestigious science center is named after him. Still insatiably curious, and refreshingly devoid of ego, he’s clearly still fascinated by the subject of his talk: Bulychaeva enigmatica, a half-inch-long semi-terrestrial crustacean that is found in only one place in the world—on a small section of beach on Lake Merritt. 

Is it a Bay native, or a non-native species from somewhere else in the world? Carlton walked us through its discovery and talked about studies over the last half-century that have probed its origins. “It remains one of the most interesting mysteries of the San Francisco Bay,” Carlton says.

For Carlton–who now lives in the appropriately named town of Mystic, Connecticut– Oakland was the perfect place to begin a distinguished, lifelong science career. As a teen, he decided to make a complete inventory of all marine life in Lake Merritt. He typed letters to experts at UC Berkeley, the California Academy of Sciences in San Francisco, the Smithsonian Institution, and the University of Southern California. He mailed the letters containing his descriptions and drawings from the Lakeshore Avenue post office. At a downtown print shop, he ordered a ream of paper, and the Rotary Nature Center graciously agreed to let him use their address as his return address. 

While still in high school, he was corresponding with marine biology experts from around the world, and receiving verifications indicating ”first record on Pacific Coast” or “first record in San Francisco Bay.” 

“It was pretty cool,” he recalls. 

Lake Merritt Beach-Hopper

One of his finds was the beach-hopper. “It lived a narrow, precarious existence,” he says: under seaweed, wood and stones on what is called the strand line in one very particular spot at the lake. He prefers not to disclose the exact location, but it is in a relatively inaccessible area that remained untouched during various lake renovations and construction projects. 

The beach-hopper requires a damp, salty environment, which Lake Merritt’s brackish tidal flow through the channel to the Bay provides. Did it hitch a ride on a ship in the 1800s or early 1900s, when ballast was often dumped in the Oakland estuary? Unlike ballast water, solid ballast could include plants, insects—and maybe hoppers. (Hence the lake’s description as an “accidental zoo.”)

For many years, it was thought that “our” beach-hopper originated in Chile, a trading partner with the Bay region for lumber and grain, but later studies concluded that it is a distinct species. “All was quiet in the beach-hopper world for 37 years,” says Carlton, until a 100-page monograph was published in 2019 by two beach-hopper specialists from Australia and Ireland. Buried in the study was the discovery that the closest relative to our beach-hoppers are actually from the Northern Pacific region and not the southern hemisphere–and that it survives in no other place except on a 100-foot stretch on Lake Merritt’s shoreline. 

Carlton is convinced that it’s non-native, and that the species it’s most closely related to is living somewhere between the South China Sea and the Kamchatka Peninsula, still to be discovered. He believes that genetic studies might help solve the mystery for once and all, and advises us to “stay tuned.”

Damon Tigue

Someone who says he’s ready to help analyze the DNA is local biologist Damon Tighe. Tighe. He designs biotechnology curriculum, trains West Coast educators for Bio-Rad Laboratories, is a big fan of Carlton’s (“He’s amazing”), and is similarly devoted to documenting the lake’s organisms. His “Barcode the Lake” project encourages citizen scientists in the community to sequence the DNA of Lake Merritt’s organisms with the goal of telling the world that our urban lake is “not a giant septic pool.” The project is on hold until the pandemic ends.  

As with Carlton’s projects from decades ago, the Rotary Nature Center is a key partner.

The center was constructed in 1953; it houses educational displays, interpretive exhibits, and a working observation beehive, and is located in the nation’s first designated wildlife refuge. Is the almost 70-year-old center still relevant? Carlton and Tighe’s answer is a resounding “yes.” 

“The Nature Center is a portal, with huge potential to keep facts about the natural world in the public eye,” says Carlton, noting what he calls the erosion of general understanding between hypothesis versus fact, citing climate change as an example. Kids in particular can be inspired, just as he was when he brought the Center his tubeworm specimen in 1962, launching all of his future searches.  

The two also agree that the pandemic provides an unusual opportunity to slow down and observe the natural life that exists all around our urban community.

Tighe suggests that people walk in the same space every couple of days and observe the small and large changes. He also challenges people to go to the lake “and try sitting, for once.” He says that after 20 minutes you’ll realize all you’ve been missing—and each person will have different observations. 

Carlton also urges people to experience the richness and vitality of our urban lake. “Pandemic or not, anybody can go down and enjoy the broad experience of the water and the calming effect of the natural world, while surrounded by an intense urban environment.”

Tighe is a big fan of the inaturalist website, where citizen scientists can record what they see in or by Lake Merritt, meet other nature lovers, and learn about the natural world. He says that a lot more observations have been rolling in to the site since the pandemic, particularly from kids. On the site, run by the California Academy of Sciences, there are 1,116 species that have been recorded at the lake, including birds, insects, mammals and fish.

In the Q and A segment that followed Dr. Jim Carlton’s presentation, someone asked if the enigmatic beach-hopper was edible. “Technically, yes,” was his reply. “I suspect it would taste like shrimp.” 

You can see Dr. Carlton’s presentation on the beach-hopper here

Future Lakeside Chats all begin at 7:00 pm.

January 8: “Stories From the Early Days of Lake Merritt,” featuring Jim Covel with the Monterey Bay Aquarium can be accessed here.

February 5: “The Earth, the City and the Hidden Narrative of Race,” Carl Anthony, Breakthrough Communities

March 5: “Birding at Lake Merritt,” Hilary Powers, Golden Gate Audubon Society

The Facebook page of Rotary Nature Center Friends can be found here.

C. J. Hirschfield recently retired after 17 years as Executive Director of Children’s Fairyland, where she was charged with the overall operation of the nation’s first storybook theme park. Prior to that, she served as an executive in the cable television industry where she produced two series, ran San Francisco’s public access channel, and advocated on behalf of the industry. She has penned a weekly column for the Piedmont Post for 13 years, and now writes regularly for EatDrinkFilms and Splash Pad News. She holds a degree in Film and Broadcasting from Stanford University. Hirschfield currently lives in Adams Point and serves on the programming team for the Appreciating Diversity Film Series showing free documentaries in Oakland and Piedmont, as well as on the advisory board of Youth Beat, a youth media training program that provides low-income Oakland students with the tools and opportunities they need to thrive in today’s workforce.



One response to “Lake Merritt: An “Accidental Zoo” with a Major Mystery”

  1. Ken Katz Avatar

    About the January 8 talk by Jim Covel, if the surname sounds familiar it’s because father was Paul Covel , the long-time Naturalist at Lake Merritt dating back to 1948. The talk will apparently include some early films his father shot.