Ke Kai Ola Veterinarian Hopeful to Save Endangered Hawaiian Monk Seal From Toxoplasmosis

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It’s been two weeks since an endangered Hawaiian monk seal began its treatment at Kailua-Kona’s marine mammal hospital against a deadly parasitic disease.

RW22, a 13-year-old male monk seal, was initially found off Oʻahu on Oct. 4 with fishing line in its mouth. Experts learned RW22 had ingested fishing gear but was also suffering from toxoplasmosis, a parasite spread through cat feces. He was transferred to the Marine Mammal Center’s Ke Kai Ola for further treatment.

On Wednesday, Oct. 20, Dr. Sophie Whoriskey, the Marine Mammal Center’s Hawaiian Monk Seal Conservation Veterinarian, spoke with Big Island Now over Zoom and described RW22 as being “pretty down.”

“His overall attitude just isn’t what it should be for a normal monk seal,” Whoriskey said. “He doesn’t have his normal energy, he just looks like he’s down in the dumps, very lethargic and overall weak.”

Aside from that, overall, the veterinarian said the animal is doing OK.

“He’s got a number of concerns that we’re obviously treating especially the obvious concern of toxoplasmosis,” Whoriskey said.

Dr. Sophie Whoris key (L), Hawaiian Monk Seal Conservation Veterinarian at The Marine Mammal Center, and Megan McGinnis (R), Animal Programs Manager, utilize a radiograph instrument to perform an x-ray on Hawaiian monk seal RW22 at the Center’s hospital in Kailua-Kona, HI. Credit Heather Stocker © The Marine Mammal Center_NOAA Permit #18786-03.

RW22 is the second seal in the past two years to come in with toxoplasmosis. While it doesn’t sound like a lot, Whoriskey said it is a fair number considering the population of the species is low.

Whoriskey said Ke Kai Ola treated the monk seal Pōhaku for 10 weeks before it succumbed to the parasitic disease last April. 

“Traditionally with these animals, they often come in really severely ill and haven’t made it when we diagnose toxoplasmosis in them,” the veterinarian said. “That being said, he’s (RW22) presenting a little bit differently than some of our previous patients have. He’s not quite as severely ill and he’s showing some signs that he’s got a little more energy each day.”

RW22 came to Ke Kai Ola suffering from numerous ailments including malnutrition and ingesting fishing gear.

“It is relatively unusual to have this many presenting ailments, both the fishing gear and the toxo(plasmosis),” Whoriskey said. “Usually, it’s one or the other. He’s a complex case for a variety of reasons.”


Whoriskey said toxoplasmosis is a difficult disease to treat because it’s a parasite that’s very successful and it can get into all of the tissues of the body. It can spread throughout the system and affect multiple different organs, but especially the brain.

The veterinarian said RW22 has a bit of a cervical twitch, a muscle spasm that can be a sign of neurologic disease.

“He’s getting sedated every day to get a whole suite of drugs essentially,” Whoriskey said. “He’s getting pain medication as well as food to boost his nutritional status and fluids to make sure he stays hydrated.”

While it’s still too early to tell, Whoriskey has hope. RW22 is more aware of their presence and moves a little bit more at night. Once he’s stabilized, she’s hopeful they can go in with an endoscope and remove the fishing gear.

“We’re hoping we can get him a second chance at life and get him out the door,” Whoriskey said.


There have been other cases confirmed in other areas around the islands.

The tricky part with toxoplasmosis is it can often present itself very acutely. It happens quickly that they get sick and then they pass away from that particular parasite. Sometimes it’s a carcass recovery rather than being able to provide treatment.

According to the National Atmospheric Administration website, toxoplasmosis is a leading cause of seal death in the main Hawaiian Islands.

The first case of toxoplasmosis in a Hawaiian monk seal was identified in 2004, and in sum, there have been at least 13 known deaths of Hawaiian monk seals caused directly by this parasite, with two clusters of cases detected in 2018 and 2020, the NOAA website states.

“Seals with toxoplasmosis are usually found dead and not all carcasses are found, so it is likely that more seals have been affected than are reported,” according to NOAA. “There are more cases of toxoplasmosis in females than males, which means that this disease has direct impacts on the species’ reproductive potential and population growth.”

Whoriskey said they’re still trying to understand how monk seals are exposed to this particular parasite.

“We know that cats are the ones that transmit the infection,” she said. “How exactly the monk seals are finding that parasite and being exposed to it is still the big question that we’d like to be able to answer to protect them.”

To help protect endangered Hawaiian monk seals like RW22 from toxoplasmosis, simply dispose of cat litter in the trash, keep cats safe indoors and tell community about how they too can prevent this disease from harming more marine mammals.

The public should keep a safe distance from monk seals and report sightings on Hawai‘i Island to the Center’s response team at the 24-hour hotline: 808-987-0765.

Report hooked, stranded, or entangled monk seals to the NOAA Fisheries statewide toll-free hotline at 888-256-9840. NOAA Fisheries also recommends these best practices to reduce injuries to monk seals when fishing.

The population of Hawaiian monk seals is estimated to be around 1,400 seals—about 1,100 seals in the Northwestern Hawaiian Islands and 300 seals in the main Hawaiian Islands.

Tiffany DeMasters
Tiffany DeMasters is a full-time reporter for Pacific Media Group. Tiffany worked as the cops and courts reporter for West Hawaii Today from 2017 to 2019. She also contributed stories to Ke Ola Magazine and Honolulu Civil Beat.

Tiffany can be reached at [email protected].
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