On Aug. 28, thousands of dying fish washed up along Lake Merritt’s shoreline, casualties of a massive algae bloom of the species Heterosigma akashiwo, a dark red-colored algae that depletes oxygen levels in the body of water it inhabits. This “red tide” event affected waterways throughout the San Francisco Bay, including the Berkeley Marina where ravenous seagulls feasted on piles of dead mussels.
Now, avid fans and stewards of Lake Merritt who have been taking stock of the lagoon’s ecosystem to see how it is recovering are encouraging others to do the same. Rotary Nature Center Friends, a citizen group that works to protect wildlife at the lake, is hosting a “BioBlitz” on Oct. 29, where residents can help conduct a survey of the animals that live in and around the lake to determine their numbers.
“I think it’s beneficial for people to connect to the environment they live in,” said Katie Noonan of Rotary Nature Center Friends. “The [fish die-off] was a shocking event, and this event helps people understand that, as humans, we do have a role in influencing things.”
Participants will be asked to take pictures of birds, fish, insects, and other organisms they see in or at the lake, and shown how to log their findings in iNaturalist, a social networking app created in 2008 by the California Academy of Sciences and the National Geographic Society to help track biodiversity worldwide.
Members of the public who cannot attend on Oct. 29 can stilll log their findings on an iNaturalist page that was created specifically for cataloging species observed in and around Lake Merritt after Aug. 28. The crowdsourced observations will aid local environmentalists and researchers in their efforts to preserve the lake’s ecosystem.
Sean Maher, public information officer for the Oakland Public Works Department, told The Oaklandside that the city will be exploring partnerships with groups that can help it manage the lake’s water quality.
James Robinson, executive director of the Lake Merritt Institute, said his group is currently in conversation with the city about how to maintain oxygen levels in the lake that are healthy for its animal inhabitants. The institute currently co-manages with the city two aeration fountains at the lake. Robinson hopes to also secure funding for a bubbler system that works by setting up hoses underwater to cover more ground. “Whenever we get a low oxygen level, we could turn that on and it would help create a consistent, healthy marine environment,” Robinson said.
While the institute and city staff discuss preventive measures to offset the impact of future algae blooms, members and supporters of Rotary Nature Center Friends are hard at work cataloging the species at the lake. Noonan said she’s been encouraged by what she’s seen. “One thing that surprised me is how quickly we saw large fish in Lake Merritt a couple of weeks after the kill,” she said.
Peggy Rehm is one of the locals who’s been busy using the iNaturalist app to document species. Rehm, who saw Chinook salmon in the lake last December, is particularly interested in spotting fish-eating birds such as ducks that dive for fish living near the bottom of the lake. Rehm was also happy to see anemones and nudibranchs, a type of soft-bodied mollusk, recently cataloged by Noonan.
“It’s super cool that they’re in this lake,” Rehm said. “I’m hoping that more of this stuff returns.”