While swimming out the back some years ago I was joined by some Maui’s dolphins. An unforgettable experience if a little scary at the time. They say they are small but a lot around a single swimmer got a bit lonely.
Maui’s & Hector’s dolphins are the world’s smallest and rarest dolphins. Up until the 1970s there were about 30,000 Hector’s around the South Island, and about 1000 Maui’s around the North Island. They are the same species and family with minor genetic differences, but look the same and can interbreed. With the introduction and widespread use of nylon monofilament gill nets from the 1970s, these numbers have plummeted to about 7,200 Hector’s in four distinct sub-populations around the South Island, and only between 55-80 Maui’s off the North Island’s West Coast. Not a month goes by without Maui’s and/or Hector’s dolphins being killed in fishing gear – and those are just the ones we know about.
The dolphins are very small, growing to no more than about 1.5 metres, they live only to about 20-25 years, start having babies when they’re 5-7 and breed once every 5 years or so. That means their population will always be slow to increase, at about 2% p.a at best. And that’s why the numbers have dropped so quickly, because we’re killing more in fishing gear than can reproduce. But in fact, we know if the nets are taken out of the dolphin habitat and human induced deaths reduced to zero, the species can rebuild to half its pre-1970s population by 2050. Even though these dolphins are critically endangered, and it doesn’t get worse than that, they can be saved.
Have a look at these documents, maps and photos and you will see that there is a big job to be done saving these unique marine mammals.
Background paper background mauis
Deaths of Mauis dolphins 57_WAITAKERE (1) (3)
Distribution of Maui’s and Hector’s Dolphins Red is Habitat Green is protected areas