Ocean traffic and jigsaw puzzles

Shipping traffic continues to grow worldwide, alongside both the speed and size of those ships. Many of the world’s busiest shipping zones cross directly into waters that are whales’ ancestral feeding, breeding and nursing grounds, or across their annual migratory routes.

Ship strikes and noisy waters

Being struck by these ships or, more gruesomely, their propellers is now a leading cause of death and permanent injury for whales. Animals either cannot get out of the way in time, or don’t even hear the ships coming – underwater background noise has doubled every decade for the last fifty years due to ship engines. This noise can be disorientating for a creature who navigates by sound, disrupting their navigation and preventing individuals from communicating with each other.

In trying to avoid this noise, cetaceans may move to quieter waters, but at other costs to their survival. If plentiful feeding grounds or calm and sheltered nursing grounds become too loud, they may be driven out to rougher waters with their calves, or to areas where food is scarce, both impacting their odds of long term survival.

You can google search ‘whale ship strikes’ and ‘whale propeller’ to better appreciate this issue, but be warned, the images and stories are distressing. This is one such example (content warning – serious animal injury).

Lessons in the museum

^{Pygmy Blue Whale, Balaenoptera musculus brevicauda, collected September 1994, Motutapu Island, Hauraki Gulf, New Zealand. Gift of the Department of Conservation (Auckland Conservancy), 1994. CC BY 4.0. Te Papa (MM002191)}

Te Papa houses the skeleton of a sub adult male pygmy blue whale that died by ship strike. When it comes to blue whales, the ‘pygmy’ part of this subspecies is all relative – this adolescent is still 20.6m long.

His skeleton is used to teach not just about how incredible these creatures are, but to educate about the man-made threats to their survival from ships crossing their migratory routes.

The huge suspended skeleton comes from a whale which was hit by a container ship off the North Cape of New Zealand in 1994. It is thought that the whale was probably resting at the surface after an attack by killer whales when it was struck. Scratches on its body were evidence of the attack. The impact of the ship smashed some of its ribs and left the dead animal wrapped around the ship’s bow.

Journey to the museum

The whale was towed to Motutapu Island in Auckland Harbour where it was hauled ashore and its flesh and blubber cut away (‘flensed’). The bones were then enclosed in sea cages where sea lice (little meat-eating crustaceans) cleaned off the remaining flesh. Te Papa and Department of Conservation staff, along with some enthusiastic volunteers, further cleaned the bones and then left them to bleach in the sun.

The whole process took many months. Afterwards, the skeleton was brought to Wellington where it was steam-cleaned to remove more of the oil. The whole skeleton was re-assembled at Te Papa in October 1996.

Assembling a whale

Assembling a whale skeleton for educational display is no mean feat. Below, Kaitiaki Taonga Collection Manager Science at Te Papa, Thomas Schultz, reflects on putting a Hector’s dolphin back together for an exhibition that would tour North America for ten years.

“In August 2007, while working as a Natural Environment technician at Te Papa, I was asked if I would like to help build whales. To be more accurate – rebuild them.

I was to assist Mike Huaki, who had been given the job of articulating all the cetacean skeletons for the Whales | Tohorā exhibition that opened at Te Papa in 2007 [and toured until 2019].

Mike had already assembled a Gray’s beaked whale, an adult female sperm whale, and was partway through a bull sperm whale and a pygmy right whale.

One of my first memories of that period is walking into the workshop and seeing a bizarre-looking half-assembled whale skeleton that appeared to be trapped in a spider web of string and rope that Mike was busily weaving around it. This was his solution to get the 36 overlapping ribs held temporarily in position so he could design and build the steel armatures to support each one in its correct position.

Building a Hector’s dolphin

After a few weeks of lifting and holding sperm whale vertebrae, ribs, and massive jaws in position while the serious engineering was carried out, I was trusted to take on a somewhat more modest project on my own. I was handed a relatively small box and told to “build a Hector’s dolphin”.

^{At the start of the articulation, the bones of the specimen need to be assembled like a puzzle. Photo by Thomas Schultz. Te Papa}

As this rare endemic cetacean is the world’s smallest dolphin this was a job on a more manageable scale for someone that wasn’t an engineer. Instead of welded steel armatures and pipes, most of the bones could be held together with stainless steel wires and adhesive. The small size did present a few problems, mainly the risk of damaging some of the very delicate bones such as the ribs while attaching them to the vertebrae.

There was also the nerve-wracking job of individually glueing each of the 106 teeth (each about the size of a grain of rice) into the jaws and holding them in the correct position until the adhesive set.

^{Hector’s dolphin specimen, partly completed, with vertebrae and ribs attached. Photo by Anton Van Helden. Te Papa}

The final product spent more than a decade touring the world with Whales | Tohorā, travelling thousands of kilometres between many venues without so much as a cracked rib. The Hector’s dolphin may not be as monumental as some of the larger whale skeletons but it is small [and] perfectly proportioned.”

^{Hector’s Dolphin (Cephalorhynchus hectori), 2007. Photograph by Michael Hall. Te Papa (86289)
The exhibition installed with the Hector’s dolphin specimen dwarfed by the pygmy right whale next door. Photo by Pat Stodart. Te Papa}

Further resources

Ship strikes & underwater noise, WWF Whales

Threats to cetaceans, WWF

Collecting the Spade-toothed whales