Source: NZ Department of Conservation
Date: 22 September 2026
The female Hector’s dolphin (Cephalorhynchus hectori hectori) was found dead on 20 August 2026. Necropsy has now confirmed she died from toxoplasmosis, a disease caused by the parasite Toxoplasma gondii.
The necropsy also found the dolphin was carrying a small male calf.
DOC Marine Species Manager Michelle Boyle says the loss of a pregnant female and her calf is significant for the threatened species.
“Hector’s dolphins are found only in New Zealand waters, and every individual is important to the population and its recovery.
“The necropsy provides valuable information about what caused this animal’s death, and helps us better understand the impact disease can have on Hector’s and Māui dolphins.”
Toxoplasmosis is caused by a microscopic parasite which can infect a wide range of warm-blooded animals. Cats are the only host in which the parasite can reproduce sexually and produce eggs (called oocysts).
These microscopic eggs are highly resilient and can survive for months, or even years, depending on environmental conditions. This gives them time to enter waterways and marine environments through contaminated soil and freshwater runoff, where they can be ingested by and infect marine mammals.
Research through DOC’s toxoplasmosis programme – in partnership with Massey University, Earth Science New Zealand, Bioeconomy Institute, Ngaati Te Ata Waiohua, and others – is helping scientists better understand the risk toxoplasmosis poses to Hector’s and Māui dolphins.
“Hector’s and Māui dolphins spend much of their time in nearshore waters, which can bring them into contact with contaminants entering the marine environment from the land,” Michelle says.
“This case is a reminder that threats to our native marine species don’t only come from activities happening at sea. What happens on land can also affect the health of our marine environment.”
DOC acknowledges Waihōpai Rūnaka, and thanks them for their support following the dolphin’s death, including allowing the necropsy.
DOC also thanks the member of the public promptly reported the dead dolphin while out naturing, allowing it to be recovered and examined.
“Timely reports like this from the public are incredibly valuable,” Michelle says. “Recovering animals for examination helps us understand causes of death and the threats facing vulnerable species.
“Every report adds to our knowledge and helps inform conservation management.”
Anyone who encounters a stranded, injured or dead marine mammal should contact DOC as soon as possible on 0800 DOC HOT (0800 362 468).
Background information
Toxoplasmosis is a disease caused by the parasite Toxoplasma gondii. The parasite can infect a wide range of warm-blooded animals, including marine mammals. Cats are the only host in which the parasite reproduces and sheds microscopic eggs known as oocysts. These can enter waterways through soil, stormwater and freshwater runoff and be carried into the marine environment.
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Original source: https://nz.mil-osi.com/2026/09/22/toxoplasmosis-confirmed-as-cause-of-death-of-pregnant-hectors-dolphin/