Stranded marine mammals are Silent Teachers

 More than H5N1 trcking

Studying the dead marine animals that wash onto Central Coast beaches can alert researchers to what’s affecting the seals, whales and others that live along the coast. Año Nuevo State Park had an outbreak of H5N1, Highly Pathogenic Avian Influenza, in elephant seals at in February. It didn’t affect elephant seals in the San Luis Obispo area, but seals and sea lions and other marine animals die of many other maladies. Their dead bodies are the focus of a non-profit established last fall, Central California Marine Animal Response Team.

Barbie Halaska, CCMART’s executive director and senior scientist, quotes eighteenth century anatomist Giovanni Morgagni, “This is the place where death delights to help the living,” a quote now standard in many pathology rooms around the world.

 

Sentinel species

“Marine animals are sentinel species,” she said. “They are long-lived in the ocean environment. We can sample them for environmental contaminant monitoring. Their bodies can reveal pathogens, ecosystem shifts. They are Silent Teachers.”

 

Marine mammals often strand when they are too sick or wounded to carry on in the ocean. The samples CCMART takes from dead animals, or the necropsy on an entire carcass, comparable to a human autopsy, may reveal not only why it died, but additional information about its life and the ocean conditions in which it lived.

Barbie Halaska, executive director and senior scientist at CCMART, measures the carcass of a California sea lion, one of the steps in data collection on stranded marine mammals. (CCMART photo)

 

Halaska and her team have examined 175 dead marine animals this year. She can’t say whether that’s a normal number, since this is the first year she’s keeping track of what’s happening along our shoreline.

 

Most California sea lions are born in June, but Halaska started seeing pups born dead or prematurely in May. The deaths may have been a result of the mother seals being sickened by domoic acid, a naturally-occurring toxin in one algae species. The seals eat the fish that eat the algae, and the toxin bioaccumulates in their bodies. The Marine Mammal Center rescued at least 13 between March and May.

 

Halaska collected a dead mature Guadalupe fur seal female, which she put in the freezer and will necropsy later. The seal weighs 85-90 lbs, and may have been pregnant.

 

“We don’t see a lot of strandings of older, mature Guadalupe fur seals,” she said.

 

Gray whales have stranded in higher numbers this year, 146 reported so far, compared to average annual numbers of 43 from 2006-2023. None have stranded on the Central Coast, found instead north of here, in San Francisco, Oregon and Washington. The deaths probably reflect changing ocean conditions that reduce the amount or quality of their prey, tiny amphipods that live in sediment on the ocean floor.

 

Usually, Halaska necropsies (like an autopsy, only with animals) the critters on the beach where they land, takes samples, and leaves the rest, covered with sand, behind.

 

“Scavengers can pull apart a carcass in a day and a half, if there’s no people around to scare them off,” she said. “The gulls appreciate it.”

 

Testing samples

Whale and seal blubber hold persistent organic pollutants, such as PCBs and PFAS (forever chemicals), and microplastics. Ear wax builds up in whales to form a lifelong plug that can be investigated to reveal events in the whale’s life history, such as hormonal changes that reflect pregnancies.

Dead marine mammals can be indicators for public health, especially sea lions that are affected by domoic acid which can be concentrated in filter feeders such as mussels, clams, and other shellfish and affect humans.

Whale baleen and seal whiskers, formally called vibrissae, can also show an extensive record of environmental contamination or even what the animals were eating before they died.

Other findings can add to knowledge of anatomy, their natural history, and the health of the population, as well as environmental contamination.

CCMART has the required special permits from State Parks and NOAA to go onto the beach to take samples from dead animals. They report every time they go onto the beach for a dead animal.

CCMART volunteers begin work to take measurements from a Risso's Dolphin that washed up dead on a Central Coast beach. (CCMART photo)

 

Nonprofit organization

CCMART is a dedicated first responder for deceased marine mammals and sea turtles in San Luis Obispo & Santa Barbara Counties. The organization is part of the National Oceanic and Atmospheric Administration’s Marine MammalHealth and Stranding Network.  The University of California at Davis handled H5N1 testing, declaring the outbreak over on March 24. 

Twenty volunteers are now trained to respond to reports of dead animals on the beach. They assess the carcass, determine the species, and measure the remains.

 

Halaska plans to hold another volunteer training session in October. All skills are welcome. CCMART is funded by grants and donations.

 

Photos such as this one, of a dead Risso's Dolphin, help guide CCMART volunteers and staff to marine mammal carcasses for evaluation. (CCMART photo)

If you find a dead animal:

 

Anyone can report dead marine mammals to CCMART, by phone, through the website, or via email 

info@ccmarineresponse.org.

Stranding Hotline: 805-242-3560

Stay back at least 150 feet. The possibility of human infection is very low, but dogs might catch something. Keep the dog on a leash.

Photos help. Try to determine the position of the dead animal in relation to the high tide line.

 

Drop a pin or include the coordinates with the report.

Having a time and location stamp on your photo app helps.

Christine Heinrichs is the Monterey Bay National Marine Sanctuary Advisory Council SLO At-Large member. Follow her on Facebook, Bluesky, LinkedIn, and Substack.

Return of the Bulls

And the living is easy.

Lots of females and young seals remain on the beach, but a few young bulls have shown up. The older bulls will follow, and males will dominate the beach for the summer.

The bulls are returning to molt their skin, as the females and juveniles are finishing their molt. The process is the same: the old brown skin peels off, starting around the eyes and ears, old scars, and other body orifices. Then the belly and sides and back peel off.

This female has several cookie cutter shark scars that started her molt. Cookie cutter sharks are small sharks, 18 inches or so, that bite into the blubber, twirl around to take a plug, and leave behind that distinctive circular scar. A good blubber meal, but not a threat to the seal. (Christine Heinrichs photo)

It takes an average of 32 days.  Seals arrive and leave on their own, individual schedules, so they are always arriving and leaving.

The new skin and hair underneath is gray. The hairs are short, but soon stand up and grow longer. Look for pearly gray seals next to brown and tan seals.

This seal shows a big shark scar. She lived to tell the tale! (Christine Heinrichs photo)

Leaving to migrate north

Juveniles and females leave the beach for their foraging grounds, along the continental shelf and out in the open ocean. The juveniles will return in the fall, for six weeks or so of rest. The females are on their long migration. They will have around eight months to put on weight and gestate a pup. They will return in January, when they come back to give birth.

The bulls aren’t at their highest weight, but they are in good condition. Young bulls, five to six years old, not yet in the breeding population, may spar with each other. Older bulls, not so much. Their sex organs shrink and they stop producing sperm and sex hormones during the summer.  The beach is quieter than during the winter breeding season. They’ll all leave the beach by late September, giving them three or four months to bulk up before returning in November and December for the breeding season.

Visitors enjoy seeing the big males. Their size, over two tons, and more than fifteen feet long, is always awe-inspiring. Their floppy noses and pink chest shields are a sight to remember when they get home.

Each rookery is identified by a different flipper tag color, connecting the seal with the beach where it was born. 

Cal Poly tagged seals

Katie Saenger, Cal Poly master’s degree student, defended her thesis to an appreciative audience at Cal Poly’s Fisher Hall in San Luis Obispo. What great weaners she tracked! Each one took a different route — in some cases, more than one migration.

Officially titled “Movement of weaned northern elephant seal pups during their first at-sea foraging migration,” she put tracking devices on a total of 25 pups over three years, 2022-2024.

See their tracks here for the first five in 2022; here for the ten in 2023; and here for 2024. Vandenberg Space Force Base paid for the study, so the first five seals were tagged there and named for Vandenberg launches. The next ten, five tagged at Vandenberg and five at San Nicolas Island, got names of local animals and plants. The third year had an astronomical theme, which included one named for Neil deGrasse Tyson.

Although most of the seals congregated in the Central Coast area, Monarch went all the way to the Aleutians and back on her first migration. I’ve written about her amazing journey. Unfortunately, since the battery on her device died, her data was not included in the data analysis, since it counts as an Incomplete Trip.

Not to say it is insignificant! What a champ.

Aurora actually turned south, on her second migration. She was one of the seals who left on her first migration, then hauled out on the beach, and then left again. This behavior was not previously identified, so Katie and the tracking devices revealed that weaners may take two or, in one case, a third migration.

The seals swim back to places where they found plenty of fish to forage on. They are learning about their ocean home, and how to survive in it.

Fox circled the Channel Islands. Frog spent some time in San Francisco Bay.

All these seals now have flipper tags to identify them in future, blue for Vandenberg and red for San Nicolas. Other colors signify other rookery locations.

I’d love to know what becomes of Monarch. Will she become a Supermom? Will Aurora explore Mexico and focus her beach life there? What’s in store for Seal deGrasse Tyson?

Katie said that following these seals through their lives is her Dream Study. Because the seals molt their skin every year, there’s no way to mark them permanently, except for the small blue flipper tags, or place permanent tracking devices on them.

TMMC releases rehabbed elephant seal pups

The Marine Mammal Center, https://www.marinemammalcenter.org/, recently released two rehabbed elephant seal pups at Leffingwell Landing in Cambria, Rocky and Carnation. As seals that have been rescued and rehabilitated, they have orange flipper tags.

Rocky and Carnation leave their carriers. They wear hat tags, 3D printed tags made of compostable/biodegradable material. The tags will soon fall off in the ocean. The pups wear them as patients so that caregivers can identify which animal is which in a pool of bobbing seal heads. Each seal has an individual medication and treatment plan. (TMMC photo Laurie Miller)

The event emphasized TMMC’s work to interconnect marine mammal care, humans, animal populations and the ocean. The problems of individual marine patients draw a direct line to global marine health and human wellbeing.

“Our work is aligned with One Health, a collaborative approach to global wellbeing that recognizes the interconnections among people, animals, plants and their shared environment,” the center said in a prepared statement.

Inviting the public to see rehabilitated seal patients released back to the ocean advances the center’s mission by engaging public support and encouraging donations.

“Threats to our ocean cannot be addressed by simply rescuing more animals. We cannot return healthy animals to a sick ocean and expect them to thrive,” the statement said.

Federal funding to support marine mammal research has been cut. Proposed legal changes, such as to the Marine Mammal Protection Act, would reduce protection and the government’s ability to defend marine mammals. The deep-water ocean monitoring system that has provided information about ocean health, climate, fisheries, and coastal flooding for ten years is being dismantled.

The center seeks support to “strengthen its capacity as marine mammal first responders, train more wildlife health professionals from around the world, and engage more children and adults as ocean stewards.”

Rocky and Carnation take different paths

Sea lions always rush for the surf. Elephant seals, not so much. Carnation took his time, but once a wave splashed over him, he was off.

Carnation is ready to go. (TMMC photo Laurie Miller) 

Rocky wasn’t ready to go. He held back, stayed on the beach, even turned around once.

Rocky is reluctant to leave. (TMMC photo Laurie Miller) 

Waves washed over him, rolling him around. He didn’t seem to like that. Once in the water, he would swim free, but at the surfline, he was rolled, again. He headed for his namesake, the rocks.

Eventually, TMMC volunteers recaptured him in an animal carrier. They put him in the van and brought him to a more isolated beach, where he returned to the ocean.

Would he rejoin his companion? Would either of them care? Elephant seals are solitary when they are out at sea. What do elephant seals think?

The seals get to keep those secrets, for now. But I’m looking for those flipper tags…