Monitoring dolphins in Dusky Sound

Dusky Sound at its best. Photo: Sarah Afriyie-Agyemang

I’d heard the talk and seen the snaps, but they just don’t do it justice. The smoke-like clouds drifting off the treetops; the silky water broken by the bobbing heads of penguins or curious seals; the dominating presence of the mountains trying to reach the ever-changing sky.

I can only describe it as mythical…other-worldly even.

Just when I thought it couldn’t get any better a humpback whale unexpectedly burst from the still waters a few hundred metres from our boat, the Southern Winds. After a blast of water from its blowhole, it slipped gracefully into the tannin stained waters waving a final goodbye with its tail. It was incredible. For the next 20 minutes DOC ranger Sanjay Thakur, Skipper Chris Pascoe and I watched as this gentle giant breached over and over again.

A magical moment to behold. Photo: Sarah Afriyie-Agyemang

We soon learnt we weren’t the only ones watching the show. A pod of dolphins came torpedo-ing in to get a better look, darting up down and over the whale. I’m no dolphin behaviour expert so I really can’t say whether they were playing, curious or annoyed, but I’d like to think the interaction was a friendly one.

I was in Dusky Sound to join the dolphin monitoring team which consisted of DOC staff Chris, Sanjay and Dave Johnson and Otago University researchers Imogen Foote and Steph Bennington. Imogen is doing her Masters of Science on New Zealand sea lions while Steph is using the dolphin monitoring data to investigate which habitat areas they use and why.

There are currently three separate bottlenose dolphin (Turcios truncatus) populations in Fiordland of which two are regularly studied, the population in Doubtful Sound and ones in Dusky Sound. The population in Doubtful Sound is one of the longest monitored populations of dolphins in the world, having been studied since the early 1990’s. The Dusky Sound population is more recent and has only been studied for around a decade.

Tooth rakes on fins are a common sight. Photo: Imogen Foote

The monitoring consists of surveying the whole fiord, which usually takes two days, over a ten-day period. The team leaves the comforts of the Southern Winds to traverse the waters on a small boat called Nemo (I was disappointed to find it wasn’t orange). Photos of their dorsal fins are taken and matched to ones in a catalogue for individual identification.

Going out and taking photos of dolphins sounds like a fun and easy job, but it’s surprisingly hard. Trying to take a good quality image of a spontaneously appearing, fast moving, non-cooperative marine mammal is about as easy as herding cats at a dog show.

Not only does the image need to be in focus (a standard requirement for a good photo), it also needs good lighting, be close-up and preferably not taken on a rainy day as the cameras aren’t waterproof. However, the ultimate test to taking a photo of a dolphin is finding a dolphin to photograph. On both days I joined the team when on Nemo we didn’t see a single dolphin.

The dolphin crew on the Nemo. Photo: Sarah Afriyie-Agyemang

Thankfully the team was more successful than I in capturing good images. Imogen and Steph were pros with the cameras. The photos they took were stunning and good enough to accurately be matched in the dolphin catalogue.

These monitoring trips are carried out three times a year and are important for understanding what is ‘normal’ for a population of a long-lived species. It helps to ensure DOC are managing the potential impacts and risks appropriately.

The research has helped establish the Dolphin Code of Management in Doubtful Sound which incorporates a range of protection measures to help reduce vessel impacts on the dolphins.

The main feature being the Dolphin Protection Zone – no-boat areas 200m from the shore when dolphins are present. These zones are in addition to the laws regarding how boats and people can interact with marine mammals.

I’m hoping my time in Dusky wasn’t a once in a lifetime opportunity because it is truly a remarkable place and I’m eager to return. I trust that my bad luck on the Nemo won’t prevent another invitation to the next trip.