Protecting Hector’s – The dolphin, the place and the research

By Will Carome, University of Otago MSc graduate – Marine Researcher

This is the second blog in the ‘Protecting Hector’s‘ series – a deep dive into a collaborative research project trying to find out how we can coexist sustainably with this rare taonga species.

Tucked on the south side of Te Pātaka o Rākaihautū (Banks Peninsula) is the peaceful and unique Akaroa Harbour, home to the world’s smallest, and one of New Zealand’s most at threat dolphin species, the Hector’s dolphin.

DOC is working alongside local tour operators, Rūnanga, researchers and the regional council to study the impacts of cruise ships, dolphin tourism and general vessel traffic in Akaroa Harbour.

Researcher Will Carome sets the scene for how the research project came to be.

I came to Aotearoa for the picturesque landscapes and stayed for the outstanding people and unparalleled access to marine life. Many of the species found in Aotearoa (including the kākāpō, wētā, and of course kiwi) are found nowhere else in the world, they are endemic. Included among these are Hector’s dolphins.

What’s a Hector’s dolphin?

Mother and calf swimming around Banks Peninsula 📷: David Johnston

Also called tutumairekurai (special ocean dweller), pahu (bang or boom), and tūpoupou (to bow frequently), Hector’s dolphins have more names in Te Reo Māori than any other whale or dolphin species. A taonga species, they are linked to tangata whenua through whakapapa. We all have a collective responsibility to protect them.

You may have heard that Hector’s are the smallest dolphins in the world (maximum 145 cm; approx. 50 kg). Just like Māui dolphins, they have a distinctive rounded dorsal fin that looks like one of Mickey Mouse’s ears and their bodies are grey with black and white markings.

Hector’s dolphins live along about a 50-km stretch of coast throughout their entire lifetime (approx. 25 years) and are rarely seen leaving shallow waters – this species shares its home with us.

Once present throughout our coasts, impacts from fishing (gillnets and trawlers) have reduced and fragmented Hector’s dolphin populations, leading to their status as an endangered species. Few strongholds remain.

Akaroa Harbour is a special place

75 km southeast of Ōtautahi/Christchurch, Akaroa Harbour is one of only a handful of spots around the world where you are more likely to see dolphins than not. A twice-daily replenishment of nutrients from strong tides breathes life into this flooded crater, left behind from a volcanic explosion some nine million years ago.

Once known for fishing, Hector’s dolphin tourism has become the main attraction in the historic French settlement of Akaroa. Beginning in 1985 with a daily natural history tour, dolphin tourism here grew to a thriving $6 million industry prior to the COVID-19 pandemic. Over 60,000 people flocked to Akaroa each year to view and swim with these ‘kiwi of the sea.’

Up close and personal experiences with rare species can leave long-lasting marks, creating opportunities for education and instilling deeper care for these charismatic creatures. However we also know, that these same experiences disrupt the normal behavior patterns of Hector’s dolphins, which may have consequences for their population.

A treasure trove of data

In 1984, Liz Slooten and Steve Dawson, Professors Emeritus at the University of Otago, began a careful study of the dolphins in and around Akaroa Harbour. Liz, Steve, and a team of students (myself included) have followed the exact same survey path for nearly forty years.

We venture out in a 6-metre research vessel, following a prescribed track whilst visually scanning left and right for dolphins. When we find a group, the vessel is carefully maneuvered closer and we photograph individuals, identified by marks on their fins, before returning to the survey path.

Akaroa Harbour survey path — Map showing a typical zig-zag survey path (dotted line) within Akaroa Harbour. Following this standardised survey path over the last two decades has allowed us to examine possible changes in the distribution of Hector’s dolphins over time.

Long-term datasets are cornerstones for monitoring populations. They can also help to answer unexpected questions.

Much has changed in the harbour during this time, including restrictions on fishing, growth in dolphin tourism, and warming waters.

Perhaps the most dramatic change to the industry occurred in the wake of the devastating earthquake on February 22^nd 2011. Substantial damage to Lyttelton Port led to the third-largest cruise ship market in Aotearoa shifting to Akaroa almost overnight.

Akaroa Harbour cruise ship stats — *Number of cruise ships anchoring in Akaroa Harbour each summer (October – April) from 2003 – 2020.*

Where do I fit in?

*Marine Researcher Will Carome at the mouth of the Akaroa Harbour*.

From a small cottage in French Farm, surrounded by native bush and birdsong, I began to delve into decades of data during days when weather kept us off the water. My task was to examine whether we (humans) influence how Hector’s dolphins use Akaroa Harbour. This included analyzing over 8,000 dolphin sightings, 60,000 images of boat traffic, and 150 days of sound recordings.

Through these blogs, I’ll be sharing my journey into understanding whether tourism has existed at sustainable levels for dolphins at Akaroa. The COVID-19 pandemic removed boats from the water and brought relief from human impacts for some species.

With international visitors again on our doorstep, should we welcome the return of pre-COVID levels of tourism? My research will help answer that question.