Bay Area/ Oakland/ Parks & Nature
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Published on June 25, 2023
VIDEO: Out-of-This-World Creature Spotted in Oakland LakeΣ64, CC BY 4.0, via Wikimedia Commons

A rower at Lake Merritt in California recently captured fascinating footage of a mysterious jellyfish-like creature propelling through the waters, sparking debates among experts on its precise identification and significance according to KTVU. The mesmerizing aquatic invertebrate with an intriguing whitish X-shaped marking across its transparent hood and mid-length tendrils appeared to be elusive, as scientists struggled to agree on its exact species.



While some experts, like Nate Jaros, Senior Director of Fish and Invertebrates at Long Beach's Aquarium of the Pacific, suggest it could be the clinging jelly (Gonionemus vertens), others argue it might resemble Craspedacusta sowerbii, a freshwater jellyfish. Meanwhile, an environmental program manager from the state Department of Fish and Wildlife proposed that it could also be a Maeotias marginata, typically found in brackish waters like the Bay and Suisun Marsh.

This isn't the first time an extraordinary specimen has puzzled experts and locals in the area. About a year ago, a similar transparent organism with spindly tentacles was spotted undulating in Lake Merritt, baffling onlookers who compared it to a jellyfish or a spider as revealed by SFGate. The alien-like creature's swimming behavior, orangish coloring, and the number of tentacles led Claudia Mills, a jelly expert at the University of Washington's Friday Harbor Laboratories, to believe it was a hydromedusa known as Gonionemus vertens or the clinging jelly.

Clinging jellyfish, unlike true jellyfish like moon jellies, are hydrozoans more closely related to Velella velella, or "by-the-wind sailors," which washed up along the California coastline earlier this year. The clinging jellyfish possess a fascinating life cycle involving hydromedusa as the active reproductive stage and a tendency to "cling" to surfaces like seagrass during the day.

While the recent Lake Merritt aquatic invertebrate's identity remains uncertain, these sightings may indicate previously undocumented populations or changes in the environment. As more sightings of mysterious creatures come to light, it is crucial to remember the importance of appreciating and preserving the rich biodiversity in the region, especially given the adverse impacts human activity can have on ecosystems.

What is particularly captivating about the recent jellyfish-like creature sighting is that it occurs amidst a broader context of unique marine life occasionally surfacing in Lake Merritt, such as leopard sharks, sea lions, and bat rays. Last year, an unusual species of jellyfish was discovered in the depths of Monterey Bay, revealing that the ecosystem is continuously evolving and surprising us in unexpected ways.