Post-mortem clears endangered Maui’s dolphin
18 January 2008
Post-mortem clears endangered Maui’s dolphin of virus
Results from a post-mortem carried out on a female Maui’s dolphin and pre-natal calf found beach-cast at Raglan late last year, have cleared the dolphin of the disease Brucellosis, but were unable to determine a cause of death.
Brucellosis can be caused by the brucella bacterium which is present in a number of marine species worldwide, like seals, dolphins and whales. The effects of the bacteria are largely unknown in the marine environment, but brucella can cause late-term abortion in livestock. There are concerns that this may also be the case in marine mammals.
Sean Cooper, Senior Marine Conservation Officer says while the death of a mother and calf is a huge blow to the remaining critically endangered Maui’s dolphins, the negative brucella result is great news for the remaining population.
“We don’t know to what extent brucella may be present within the Maui’s population, so it is very positive news it was not in this dolphin.”
In 2006, an immature Maui’s dolphin found dead at Raglan beach tested positive for the bacteria which sparked fears that others in the population may also be infected. The results of that post-mortem did not suggest the bacteria as the cause of death, but the presence of brucella was a real concern.
Maui’s dolphin is considered a critically endangered species with an estimated 111 individuals remaining. Maui’s is a sub-species of the Hector’s dolphin - the worlds smallest and rarest marine dolphin found no where else in the world, New Zealand’s only endemic dolphin.
Females have only one calf every two to four years and do not reach breeding age until they are seven to nine years old. Potential for recovery of the species is extremely slow.
Maui’s dolphins are now restricted to the west coast of the North Island. The majority of the population is spread in small groups between the Manakau Harbour and the Waikato River, with isolated groups to the south and north.