By RNZ
A pregnant Hector’s dolphin found dead on an Invercargill beach died from toxoplasmosis.
The dolphin was carrying a male calf when it was found on Ōreti Beach on August 20.
The Department of Conservation (DoC) said toxoplasmosis is a parasitic disease that reproduces in cats and is a significant threat to dolphins.
DoC marine species manager Michelle Boyle said the loss of the female and her calf was 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,” she said.
Around 15,000 Hector’s dolphins over the age of one remain.
Cats are the only host in which the parasite can reproduce sexually and produce eggs.
Boyle said the microscopic eggs could survive for months or even years, depending on environmental conditions, giving them time to enter waterways and the sea through contaminated soil and freshwater run-off.
“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,” she said.
“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.”
Timely reports of dead animals were valuable because examination helped DoC understand causes of death and threats faced by vulnerable species, Boyle said.