It's Raining Anchovies! Fish Fall From the Sky in San Francisco

Earlier this month, Reddit user sanfrannie wrote that a friend's roof and back deck in the Outer Richmond were inundated with about a dozen 8-inch silverfish. Others who commented shared similar experiences. One witness claimed they heard a "whoosh" sound behind them and then a loud splat, after which they noticed fish all over a nearby driveway. Another person said they were waiting for a bus in the Castro when they almost got hit by a fish. A third witness claimed they saw several fish fall onto an Outer Richmond sidewalk and assumed a group of roving kids was participating in a Tik Tok sardine-throwing challenge on a roof somewhere.

Seabirds vs Anchovies

Seabirds could not survive the anchovy overpopulation off the coast of the Bay Area, according to local fishermen and researchers.

People are telling Larry Collins, president of the San Francisco Community Fishing Association, that they have never seen bait this thick from Half Moon Bay to Point Reyes. Collins recently heard tales from men who claimed that thousands of birds were simply sitting on the water there with anchovies in their mouths because they were unable to eat anymore.

Jim Ervin, a retired laboratory analyst at San Jose's Environmental Services Department, claimed in a blog post published on June 11 for the Otolith Geochemistry & Fish Ecology Laboratory at UC Davis, that the anchovy population in Lower South San Franciso Bay has recently experienced an explosion.

Really Cold Water

The monthly totals for April and May were 29 and 52, respectively, according to Ervin's blog. For the June trawls, the overall tally increased to over 2,600. The monthly total for this period is the second-highest ever.

The Marine Mammal Center in Sausalito's associate director of conservation education, Adam Ratner, attributes the phenomenon to upwelling, a natural process in which cold, nutrient-rich water rises from the ocean's depths to replace warmer water on the surface.

According to Ratner, the current water temperatures do appear to be colder than usual, and this has given animals like anchovies, seabirds, and marine mammals some much-needed food. The duration of this brief period of cold water is unknown, and due to climate change, the trend is toward warmer water temperatures becoming the standard. He continued, saying that for the time being, this seems to be giving local sea lions, migrating whales, and fishing communities some extra support.

Collins claims that the anchovies are evidence that this year's water is the coldest that local fishermen have experienced in a long time.

Making it Rain

Collins emphasized that the ocean is currently in excellent health. He mentioned that some people have observed seagulls simply skimming the surface of the water and filling their mouths with anchovies rather than diving for food.

Birds like these pelicans are almost certainly to blame for the fish that are raining down onto city streets, SFGate reports.

Whitney Grover, interim deputy director at the Golden Gate Audubon Society, said that currently, there are a lot of anchovies near the shore. She explained that the reason fish sometimes fall from the sky is that many seabirds are out fishing, and if they fly back over land on their way to somewhere else, they occasionally drop fish.

According to Grover, some bird species, such as the double-crested cormorant, prefer to stay farther inland, close to freshwater lakes but will migrate to the coast when there are abundant fish to eat. On their daily foraging routes, brown pelicans also frequently fly great distances. Birds like these might explain why people in areas like the Castro have to avoid falling fish, similar to the post on reddit.

Grover reported that she could see the seabirds flying directly over San Francisco and the Castro before heading into the bay after visiting Ocean Beach and collecting some anchovies.

Large numbers of marine mammals that eat forage fish have also arrived thanks to the boom in anchovy population.