It’s not just a bloom—it’s a biological crisis that’s killing animals faster than rescue teams can respond.
What’s happening off the California coast isn’t some seasonal weirdness or minor environmental hiccup. It’s a full-scale wildlife emergency, and it’s playing out in real time. A massive toxic algae bloom, driven by warming waters and excess nutrients, is sweeping the Pacific and killing marine animals at an unprecedented rate.
In just the past few months, confirmed deaths include sea lions, dolphins, whales, and seabirds—many in numbers that local experts haven’t seen in years. Marine mammal rescue centers are flooded with calls, operating beyond capacity, and losing more animals than they can save. Here’s what’s actually unfolding under the surface—and why it’s hitting harder than anyone was ready for.
1. Sea lions are dying in record numbers, and rescue centers can’t keep up.
According to California’s Marine Mammal Center, they have received over 1,000 calls since January 2025 about sick or stranded sea lions, most of them suffering from domoic acid poisoning. These animals don’t just look lost—they’re having seizures, collapsing in public spaces, and in many cases, dying on the beach before help arrives.
The domoic acid, produced by Pseudo-nitzschia algae, enters their system through contaminated fish like sardines and anchovies. Once it’s in, it causes permanent neurological damage. Some animals foam at the mouth or twitch uncontrollably. Others wander into traffic or circle in place until they collapse.
Rescue teams are doing triage at this point. Not every sea lion can be saved, and the ones that do make it to care are often too far gone. Euthanasia rates have spiked. The Center says it’s one of the worst years they’ve ever seen, and they’re operating around the clock just to keep up.
2. Entire dolphin pods are beaching, and many don’t survive.
Dolphins are washing up in clusters, showing the same domoic acid symptoms as sea lions—only their social nature makes it worse. When one dolphin loses its bearings and beaches itself, others often follow. As reported by NOAA Fisheries, in March and April 2025 alone, dozens of dolphins have been found dead along stretches of Ventura, Santa Barbara, and Los Angeles County.
These aren’t isolated cases. They’re full-blown mass mortality events. Disoriented dolphins flail in shallow water, some with visible tremors. Volunteers try to guide them back out, but many return or die before rescue is even an option.
The neurological impact from the toxin is so severe that it can damage echolocation and motor control. Once that’s compromised, dolphins can’t feed or communicate effectively—and that spells disaster for an animal that depends so much on the group to survive. For most of these pods, the outcome is grim.
3. Whales are dying too, including at least one confirmed domoic acid death.
Whales aren’t usually affected in huge numbers, but even a few deaths matter when each animal is massive, long-lived, and already facing pressure from ship strikes and habitat loss. In April 2025, a gray whale was found dead in Southern California, and necropsy results confirmed domoic acid exposure as a contributing factor, as reported by Cheri Carlson at The Ventura County Star.
That’s huge. Whales usually feed further offshore, where waters were once thought safer. But with this year’s bloom stretching hundreds of miles and spreading deeper into open ocean, even they’re no longer spared. Affected whales may not beach themselves, but the signs are there—erratic swimming, emaciation, and altered migration routes.
Whale researchers are scrambling to adjust tracking programs. Sightings are down. The whales that do appear are moving unpredictably. And for many coastal tour groups and scientists, the loss of these animals is personal. Their absence is more than symbolic—it’s a warning.
4. Pelicans and seabirds are dying in massive numbers from toxic fish.
Bird rehab centers from Monterey to San Diego are reporting surges in sick and dying seabirds—especially brown pelicans, as noted by Ariana Gastelum for the International Bird Rescue . These birds, already vulnerable after past population crashes, are now suffering neurological symptoms identical to what’s been seen in mammals.
It starts with unsteady flight. Some crash midair. Others plunge into buildings, roofs, or roads, too disoriented to land safely. And because they eat the same anchovies and sardines that concentrate domoic acid, the exposure is consistent and severe.
In April alone, hundreds of dead or dying birds were recovered from beaches across Northern California. Many don’t survive transport. Rehabbers say they’re beyond capacity and turning away mild cases to focus on the ones who still have a shot. Even those who recover often can’t be released—they’ve lost their sense of direction or balance completely.
5. Elephant seals are arriving underweight and leaving fewer pups alive.
Normally, elephant seals bulk up at sea before coming ashore to breed. But this year, more of them are showing up underweight, disoriented, or just plain weak. Scientists at Año Nuevo and Piedras Blancas have noted a visible decline in body condition—especially in females, whose pups depend on those fat reserves to survive.
The bloom hasn’t just poisoned prey—it’s pushed it elsewhere. That means longer travel times, deeper dives, and more energy burned just to feed. For animals that fast while nursing, that deficit is devastating. Pups are being born smaller and weaned faster, with fewer surviving long enough to head out to sea.
The ripple effect is huge. Every poor breeding season takes years to undo. And while elephant seals are resilient, this kind of disruption—especially back-to-back—starts to wear down population stability.
6. Dead zones are forming fast, and they’re clearing out everything beneath the surface.
It’s not just the algae itself. It’s what happens when it dies. As the bloom crashes, the massive decay process consumes oxygen in the water, creating hypoxic zones that suffocate life across the board. These “dead zones” are already appearing along central and southern California’s coastline.
In these low-oxygen areas, fish flee if they can. Crabs, invertebrates, and juvenile marine life don’t get the same chance. They die in place, sometimes in huge numbers. For local fisheries and food webs, it’s catastrophic.
Boats are hauling in empty traps. Divers are reporting eerie silence in once-vibrant kelp forests. And because these zones form so fast, they leave little time for recovery or escape. What was once a thriving stretch of water becomes a biological desert.
7. Otters are showing signs of neurological distress tied to algae-contaminated shellfish.
Southern sea otters, already listed as threatened, are showing up twitchy, dazed, and sometimes aggressive. Rescuers report behavior changes that line up with domoic acid poisoning—and the cause is likely their diet. Otters feed heavily on mussels, clams, and other shellfish, which absorb toxins during bloom events.
The smaller the animal, the faster the damage takes hold. Otters have been found floating in harbors unresponsive, struggling to swim, or attacking handlers out of confusion. These aren’t isolated rescues—they’re stacking up, and biologists are beginning to track patterns that suggest broader population stress.
If these blooms continue at the same pace, otters won’t just be impacted—they’ll lose ground. And with such a limited range and small numbers, that’s a risk the species can’t afford.
8. California’s shellfish industry is shutting down as toxin levels spike.
Public health warnings have shut down commercial and recreational harvesting of mussels, clams, and crabs in multiple California counties since February. The toxins aren’t just dangerous for people—they’re deadly to animals too. Otters, seabirds, and many fish rely on these species, and now they’re either gone or poisonous.
The closures are based on routine testing, but this year, the alerts have come earlier and lasted longer. Restaurants are pulling items from menus. Coastal towns that depend on shellfish income are hurting. And meanwhile, wildlife that doesn’t know the shellfish are toxic just keeps eating.
Wildlife agencies are scrambling to increase monitoring, but the speed of the bloom has outpaced response time. In places where shellfish used to be a cornerstone of the ecosystem, there’s now just risk.
9. Many marine mammals that survive the bloom are neurologically compromised for life.
Not every animal dies right away. Some sea lions and dolphins make it through the initial symptoms with help from rescue teams. But even those survivors often suffer long-term consequences—balance issues, impaired hearing, memory loss. And once they’re released, they rarely fare well in the wild.
Rehabilitation centers are reporting that more animals are coming back after release. Others are found months later, stranded again, showing the same symptoms. This kind of chronic neurological damage means they can’t hunt properly, avoid predators, or reintegrate with their pod.
It’s not enough to treat the symptoms anymore. The underlying issue—the repeated, large-scale exposure—is what’s creating a population of animals that can’t fully recover. That’s a much harder problem to solve.
10. The fish themselves are changing—and it’s affecting everyone who eats them.
Fat content, migration behavior, and breeding cycles are all shifting in small fish like sardines and anchovies. These are the foundation of the coastal food web. And they’re responding to the bloom by becoming harder to find, less nutritious, and more toxic.
For dolphins, sea lions, pelicans, and whales, that change is devastating. They might still catch fish, but they’re not getting the same energy. And if they eat enough contaminated individuals, they’re exposing themselves to lethal doses of toxins over time.
Researchers are calling it a “nutritional trap.” The food looks the same, but it’s delivering less—and sometimes, poisoning the animals outright. That’s not just a short-term shift. It’s a recipe for collapse if it keeps going.
11. California’s algae blooms are growing bigger, longer, and more dangerous every year.
The bloom that started this winter didn’t fade like it used to. Instead, it grew, stretched, and returned in waves. By April 2025, it had expanded across hundreds of miles of coastline, with domoic acid levels hitting records in multiple counties.
This isn’t a freak occurrence anymore. Warmer waters, pollution from agriculture, and shifting ocean currents are making these events both more frequent and more intense. Wildlife isn’t getting a break between blooms—it’s just trying to survive in a cycle that never really stops.
Marine mammal rescue centers say they’re bracing for another wave even while dealing with the current one. Volunteers are burning out. Budgets are stretched thin. And the animals keep coming. This isn’t just an emergency—it’s the beginning of something longer, and much harder to fix.
12. Don’t Try To Help A Sick Animal Yourself
If you see a stranded or disoriented marine animal—especially a sea lion, dolphin, or seabird—don’t approach or try to help it yourself. Many are sick, highly stressed, and could bite or injure someone without meaning to. Instead, call your local marine mammal rescue center immediately. In California, that often means contacting The Marine Mammal Center at 415-289-SEAL or Channel Islands Marine & Wildlife Institute at 805-567-1505. If you’re not sure who to call, the NOAA stranding hotline at 866-767-6114 can direct you to the right team. Quick reporting could be the only reason an animal gets treatment in time.