Your Reminder That Oakland’s Lake Merritt Is Home to Bat Rays

Don’t be worried if you see one. If anything, rejoice — because it means the SF Bay Area lake is in its comeback era.

Oakland’s brackish loch — the largest lake of its kind (one that contains both fresh and saltwater) in any urban area in the country — has a reputation for being a cesspool. And yes: It’s still a pretty bad idea to go for a dip in it, no matter how hot the weather gets outside.

However, there are signs that the lake is on the up and up regarding its health. Take for example the populations of salmon, sturgeon, and leopard sharks that have navigated through the lake in growing numbers over the past few years. But perhaps the most jaw-dropping example of Lake Merrit’s more exotic marine fauna that has returned is the bat ray.

And they almost immediately captive widespread fanfare on social media, whenever they do pop up; a video of a few bat rays vibing near the shore at the brackish lake was upvoted hundreds of times on Reddit last year.

Bat Rays in Lake Merritt
by u/snyderab0514 in oakland

In July of 2021, an Oakland resident filmed a bat ray, the most common type of eagle ray found in the San Francisco Bay Area, cruising inside Lake Merritt — and it soon became a hyperlocal viral phenomenon.

“After 8 years of either walking or running around Lake Merritt nearly every day, this is the first time that I’ve ever seen a fish longer than [two inches],” Reddit user danbob138 wrote about his uploaded video. “[The footage] was taken from the bridge on the side where the courthouse is.”

As spectacular as this sighting was, it’s by no means the first time a bat ray has been found inside the 140-acre body of water. Other marine oddities, like leopard sharks and ocean-going sturgeon, have also been recorded lurking beneath Lake Merritt.

Bat rays, like their more famous stingray cousins, eat a variety of marine prey; rays require the water they occupy to support certain filter feeders they consume. (The sizeable cartilaginous fish also feast on small marine animals.

So akin to a vociferous canary in a coal mine metaphor: The presence of this bat ray is a good indicator that the lake is, in fact, habitable for marine life.

(Because you’re probably wondering how this bat ray got into the lake in the first place: a narrow channel connects Lake Merritt to the San Francisco Bay, through a grate has been installed to trap large debris from entering into the nearby bay. But because bat rays have no bones — remember: their bodies are made from malleable cartilage — the fish probably managed to wiggle its way through, unharmed.)

Here’s hoping more of these shark kin continue to find their way in and out of Lake Merritt successfully.

For more information on Lake Merrit’s peculiar array of marine flora and fauna and how you can help conserve them for generations to come, visit lakemerrittinstitute.org/wildlife.