DOC Confirms Cat Parasite Killed Pregnant Hector’s Dolphin

The Department of Conservation (DOC) has confirmed that toxoplasmosis was the cause of death of a pregnant Hector’s dolphin recovered from Oreti Beach in Invercargill.

The female Hector’s dolphin (*Cephalorhynchus hectori hectori*) was found on 20 August 2026. A subsequent necropsy confirmed the animal died from toxoplasmosis, an infectious disease caused by the microscopic protozoan parasite *Toxoplasma gondii*. Examination also revealed the dolphin was carrying an unborn male calf.

Hector’s dolphins are endemic to New Zealand coastal waters, classified as a threatened species. DOC Marine Species Manager Michelle Boyle says the loss of a pregnant female and her calf is significant for the threatened species, and that every individual is important to the population and its recovery. Hector’s and Māui dolphins spend much of their time in nearshore waters, which DOC says can bring them into contact with contaminants entering the marine environment from the land.

According to the Merck Veterinary Manual, felids (members of the cat family) are the only definitive hosts of *Toxoplasma gondii*, and they contaminate the environment with oocysts shed in their faeces. DOC says these oocysts (eggs) are highly resilient and can survive for months, or even years, depending on environmental conditions, and can be carried into waterways and the sea through soil, stormwater and freshwater runoff.

DOC’s toxoplasmosis information page lists steps cat owners can take to help prevent the parasite reaching Hector’s and Māui dolphins. DOC advises disposing of cat faeces in the rubbish bin, not the toilet. Oocysts can reach waterways through wastewater when cat faeces or kitty litter have been flushed, and DOC notes they cannot be treated by standard wastewater treatment methods, such as UV radiation.

DOC’s other suggestions for cat owners include keeping cats indoors, spaying or neutering your cat, and not abandoning unwanted cats or feeding feral cats. For how to bag and bin used litter, see the disposal section of our best cat litter in New Zealand guide. Anyone who encounters a stranded, injured or dead marine mammal should contact DOC as soon as possible on 0800 DOC HOT (0800 362 468).

Sources

• https://www.doc.govt.nz/news/media-releases/2026-media-releases/toxoplasmosis-confirmed-as-cause-of-death-of-pregnant-hectors-dolphin/
• https://www.merckvetmanual.com/infectious-diseases/toxoplasmosis/toxoplasmosis-in-animals
• https://www.doc.govt.nz/nature/pests-and-threats/diseases/toxoplasmosis-and-hectors-and-maui-dolphin/