Figuring out who’s who in the Kaikoura Canyon

Today played out at a slower pace than yesterday. The stuck tag remained elusive and the weather precluded any thought of small boat activity, so we retreated to the town of Kaikoura for the night.

Our tracking crew climbed a hill and were able to get a bearing on the missing tag had finally released from its whale. So we all went back out in the Alucia, homing in on the tag's signal, and were able to recover it. The malfunction had been caused by seawater entry into the tag. It is now winging its way to Woods Hole in the hope that it has retrievable data.

Today was a relatively quiet day, so we thought we'd give you some background on why it is so useful to photograph marine mammals so carefully and systematically.


Figuring out Who’s Who in the Kaikoura Canyon: How sperm whales tell us their stories

A sperm whale surfaces after a long dive

The ability to identify an individual whale from photographs, or photo IDs, of the animal taken during short encounters at sea allows scientists and naturalists to assemble the pieces of a very large life-history puzzle one image at a time. Coordinated efforts have produced photographic catalogues for many marine mammal species including sperm, right, blue, and humpback whales, to name a few.

From the information in the ID catalogues, researchers can piece together an animal’s migrations and pattern of habitat use on scales from one day to a period of years. We can also use photo-ID data to estimate how many animals are in a given population, how long they live, how often they have calves, and who they prefer to hang out with.

February 19, 11:16 a.m -

Our photo-ID work here in the Kaikoura Canyon is focused on sperm whales. We are contributing to the sperm whale catalogue compiled by the Marine Mammal Research Group at University of Otago. As more and more photographed sightings of each catalogued individual are collected during a day, from day to day and even over months and years across many locations, the story of the lives of individual whales is developed into an epic tale--or, in the case of the sperm whale, an epic tail.

Photographing sperm whales is the epitome of hurry-up-and-wait. The researchers on the photo-ID boat track a whale’s movement underwater with a directional hydrophone for 30 minutes to an hour; the goal is to be within a few hundred meters of the whale when it announces its presence at the surface with a robust exhalation.

February 19, 12:18 p.m.

The vessel eases over to the now surface-resting whale, staying about 75 meters astern to be ready when the animal hoists its flukes and reveals the unique markings along the trailing edge of its tail. Photographers are positioned on the bow of the boat, at the ready with hefty cameras held at eye level (the favorite is a Nikon D3 with a 300mm lens). Now it is just a matter of firing off a series of shots as the whale lifts its flukes skyward to sound for another feeding dive. Squid and fish of the Kaikoura Canyon beware!

On the right are images of a whale we’ve already seen multiple times on this trip. The nicks and notches on the fluke make it very distinctive. With each photographed sighting, we collect time, position (in latitude and longitude), as well as dive and surface intervals. At the end of Day 2 we had three sightings of the same whale, which gives us and idea of its movements and an its preferred habitat. Two days later we identified it again, still hanging out in the same area.

February 19, 3:01 p.m.

The fun part begins once we are back at our computers, where we can compare the images from the day to the ones in the sperm whale catalogue to search for a match. This time, we checked our email first and it turns out that the image of the sperm whale dorsal fin posted in our second blog entry has already been recognized by the experienced eyes at Whale Watch Kaikoura as a whale known as Tutu. Sure enough, Tutu is also in the University of Otago sperm whale catalogue, but with the slightly less prosaic name of HL160. Looking back through our records tells us that HL160 has been seen at Kaikoura regularly since 1991—a true local!

February 21, 9:13 a.m.

The more photos, the merrier the knowledge. The sperm whales of New Zealand have let us learn a lot about their personal histories, and the longer the photo-ID project goes on, the more powerful that resource become.

All images on this page by Will Rayment, University of Otago.