Nyree Sherlock, Museum Assistant
Fish display an incredible array of adaptive features to survive their underwater worlds, and this is highlighted in Kiwi North’s Life And Tides marine exhibition, which is not only visually stunning, but full of fascinating research to educate enquiring minds of all ages. For example, the exhibition displays a life-sized re-creation of a Moonfish (Opah)- a species renowned as the only known fish that is warm-blooded, in contrast to most fish that have body temperatures matching their surrounding waters, and are therefore cold-blooded. However, the Moonfish found an ingenious way to adapt to survival in the chilly ocean depths millions of years ago, by raising its body temperature to a constant 5 degrees Celsius warmer than its ocean surrounds.
This amazing adaptive feature makes the Moonfish a true marvel of evolution: by producing heat through the constant flapping of wing-like pectoral fins, it minimises heat loss through an especially adapted set of blood vessels in its gills. The two sets of vessels are tightly bundled against each other, so that the incoming blood vessels warm up the outgoing blood before it goes anywhere else. This unique heat exchange within the gills allows the fish's entire body to maintain an elevated temperature, known as endothermy, regardless of the depth of its dive.
Unfortunately the world’s oceans are heating up, and in a sad irony the remarkable Moonfish will soon face survival challenges, due to its warm-blooded nature. For example, to avoid overheating, the Moonfish may exhibit some behavioural changes such as migrating to deeper, cooler, or more shaded waters; it may also have to adjust its prey preferences or feeding locations due to the increased temperature changes. Additionally, it may increase its fin flapping to dissipate excess heat and regulate its body temperature. All in all, the Opah’s survival depends upon its ability to quickly adapt to new temperature conditions, and to maintain its warmth without overheating.
Nowadays an increasing array of marine creatures are endangered, and one of these is the Maui dolphin, an endemic species of Aotearoa, which is critically endangered with only 55 left. The taxidermized Maui dolphin that you will see in Kiwi North’s Life And Tides exhibition was created by taking a mould off a deceased Maui dolphin found on a West Coast beach around 40 years ago. The preserved form of this rare animal allows us to get a close look at the animal’s size and form, and to appreciate its fragility and vulnerability- in this case, skilled taxidermy provides a rare glimpse of a marine animal that most of us will never see in our lifetime, while simultaneously highlighting the dire need for its protection. Museum visitors are encouraged to participate in a visual petition to help the Maui Dolphin’s plight.
Taxidermy is incorporated in further innovative ways throughout the Life And Tides exhibition, revealing rare creatures that have become stranded on our pacific shores through some strange fluke of nature, such as the magnificent Indo-Pacific Sailfish, or the mysterious Crested Bandfish, which is still a little-known species. These are only two examples of the many unique and fascinating creatures whose specific adaptive features have evolved over millions of years to enable their survival. Run your hand over the taxidermy touch-plates that were especially developed for this exhibition to enhance people’s understanding of the incredible variations of fish textures, from the smooth-skinned species that glide through water, to the slower types that hover in their protective bony amour.
The Potbellied Seahorse is yet another of these incredibly designed sea creatures, with its distinctive long-snouted horse-like head, a pot-bellied body that is covered in protective bony cartilage-plates, and a long-coiling square tail that is as strong and flexible as a human hand! When scientists closely examined this tail, they found that the overlapping square-shaped segments provided better armour and a greater gripping capacity than a cylindrical tail. This biological discovery, found in the adaptive feature of a marine creature, is an inspiration in engineering, which is being investigated and could lead to building better robots and medical devices in the future.
Seahorses continue to amaze people around the globe as the only animal species in which the male seahorse gets pregnant and gives birth to the babies! These seahorse dads carry their babies in a pouch, a bit like kangaroos do, and give birth to live young. If you have never seen a live pot-bellied sea horse, there is an opportunity to do so at our Curator’s Talk and Seahorse Encounter coming up at Kiwi North this month. You will meet live pot-bellied seahorses, become entranced by their textures and movements, and gain a deeper understanding of this unique variety (hippocampus abdominalis)- a very special creature of our coast.
