Constance Taylor on June 19th, 2014 show us that the estuary Lake Merritt — sitting in the middle of a now dense Oakland — was once much more. It’s muddy tidal flats used to extend to where three of Oakland’s theaters sit, the Paramount, the Grand Lake, and the old parkway. It’s tidal channel was huge. The edges of the estuary were thick with grasses, tule, pickle weed, willows, and oak. Salmon, grizzlies, and elk could be found there, ducks could blacken the sky. The Ohlone, hunted there.
In the 200+ years since the Spanish came, the lakes edges have been gradually swallowed up by our streets, the mud flats covered. The “lake” is still connected to the bay and is influenced by its tides, but the waters are now regulated by a flood control station, so the tidal flushing is much less than it once was. The inflows are still there, but rains and our water systems bring down everything we leave on the street, trash and more.
And yet, life still seems to thrive here. Part of this is due to the protection the lake received early on. Mayor Merritt in the 1860s had a house built nearby and (so the story goes) got fed up with hunters when a cow of his was shot. It was declared a wildlife refuge in 1870, the first of its kind (at least in the West), and became a model for protections placed on other parts of the country. Bird islands were constructed at various times to allow for nesting habitat, and the islands, and parts of the waters remain off limits to people and their boats. Recent renovations thanks to a ballot measure are working on the tidal channel, exposing more mud flats, and making the channel more channel like (most prominently reworking where water flows under streets).
A recent bioblitz species survey done by the volunteers turned up 236 species in 5.5 hours of looking. Cormorants nest there most prominently, but you can also find black crowned night herons, snowy egrets, great blue herons, brown & white pelicans, caspian terns, cooper’s hawks, red tailed hawks, hummingbirds, grebes, crows, ravens, canadian geese, and all manner of gulls, ducks, and song birds. Some of these like pelicans, egrets, and night herons weren’t seen here 30 years ago — they’ve come back from the brink after DDT did in their numbers.
You might also find things like the white line sphinx moth, the hummingbird moth, pseudoscorpions, a species of sand hopper crustacean that only lives in a small stretch of sand in Lake Merritt and in Chile.
There’s raccoons, squirrels (brought in by homesick easterners), skunks, and feral cats. There has also been and an otter which showed up one day in 2013.
In the water (which at its deepest is 10′) holds smelt, herring, moon jellies, bat rays, and leopard sharks. Come at the right time and you’ll find brown pelicans patrolling the shores diving, or at other times white pelicans floating scooping wide swathes of water. You can watch cormorants, coots, and eared grebes swimming through the water chasing small fish with astonishing agility.
There are also our invertebrates like spaghetti worms, crabs, snails, zooplankton, tintinnids, and phytoplankton. Much of the plants around the lake have been cultivated and planted there, but in the water there grows widgeon grass (which periodically gets mowed), and pickleweed still appears around the lake (both planted and volunteered). The oak trees that are on the north side of the lake would have been there, though those too were cultivated — by the Ohlone. The Ohlone also made use of the California buckeye fruit as a fish poison (interestingly it is also toxic to European honey bees).
There’s also plenty of fungus — death’s caps, honey mushrooms, jack o’lanterns, and lattice stinkhorns can be found in the wetter parts of the year.
There’s slime algae & diatoms, sea lettuce. Bacteria mostly harmless, but occasionally the birds are still affected by avian botulism causing limp ducks. There hasn’t been an outbreak since 1971 — perhaps because of improved tidal flushing that has been managed over the years since.
Archaea are also found in Lake Merritt once thought only to be found in extreme environments — they are also common in mudflats where there is low oxygen. They help produce the methane which is responsible for some of what you might smell near Lake Merritt.
With all these things – all these representatives of all our kingdoms of flora and fauna – Lake Merritt is a fun place to visit and look for things.
We hope that we can see even more improvements to the environment over the years — the estuary though is a popular destination for all sorts of activities. Keeping it nice and making it better is not just the responsibility of our government, but you and me. The Lake Merritt Institute (http://www.lakemerrittinstitute.org) has long been helping to make it a cleaner and better place, but there is always plenty of trash to pick up, and they have self cleaning stations around the lake. You can also explore the wild side of Oakland at the Rotary Nature Center and with Constance’s organization Wild Oakland (http://wildoakland.org).
SF Natural History Series 