A while ago some colleagues at the Canadian Museum of Nature contemplated the production of a book on the fish that swim the oceans of the Arctic regions of Canada. That is a great topic for a museum that has one of the best collections of Arctic fishes anywhere. I have had many opportunities to plunk into the ocean to catch those creatures, so I added to the enthusiasm and commented that it was something that would be relatively easy, since there weren’t too many species. For a guy like me who sampled everything that was possible to catch while SCUBA diving, the list was certain to have fewer than 50 entries.

My eyes were opened wide when our fish experts Brian Coad, Claude Renaud and Noel Alfonso countered with their more-complete knowledge of what lives in those cold waters, based on their experience with collections that were taken in deeper waters and now preserved for study in museum collections all over the world. There are well over 200 fish species lurking below the surface.

Not a slim volume at all, this forthcoming Arctic Marine Fishes of Canada. It’s one that has never been done before and that will compile a great body of knowledge. The publication is being done with our partners, the Department of Fisheries and Oceans and the University Toronto Press.

Platytroctes apus.
A scientific illustration of the tube shoulder Platytroctes apus, by Albert C.L.G. Günther. The illustration was first published in 1887, in the Report on the Deep-Sea Fishes Collected by H.M.S. Challenger During the Years 1873–1876. The Biodiversity Heritage Library posted the report online. Image: Albert C.L.G. Günther © Public domain

A comprehensive summary of knowledge like this often comes from museums because they are close to the sources of information, and have the expertise to put it to good use. But there are always surprises, even for the experts. At the last minutes of finishing the text for this book, new species of fishes were still being discovered in the Arctic and sent to us… and no doubt will continue to arrive once the book is published. It is a humbling reminder that the ocean is a big place, and that we still have a lot to learn about it.

One of those last-minute additions to our fish book is worth talking about because it is a curious fellow. First of all, any animal that can operate year-round with its body parts chilled to near zero Centigrade is pretty remarkable. These new arrivals to the book are rarely detected in these far northern reaches. The tube shoulder (Platytroctes apus), is one of 13 species in this family that are found in Canada, five listed in the Arctic.

These small creatures grow to almost 30 centimetres and are well adapted to life in continuous darkness; never going near the surface or the bottom, it spends its entire life between the depths of 300 metres and 5000 metres. Its large eyes enhance the ability to detect any bits of light, including that produced by other animals (bioluminescence), a common feature in the deep sea.

The tube shoulder derives its common name from a unique feature that puts it into the James Bond of fishes category, a gland that produces a luminescent green-blue fluid that is excreted backward from a pore on each shoulder. It’s a strategy that is meant to confuse predators that are charging from behind. (Other equally special organisms will soon be on exhibition at the museum in Creatures of Light: Nature’s Bioluminescence).

The scientific name of this new discovery is more descriptive: Platytroctes derives from Greek for “flat-nibbler”, referring to body shape and its mouth parts, and apus from Greek for “without a foot”, referring to the absence of pelvic fins.

A Boa Dragonfish.
An X-ray of a Boa Dragonfish (Stomias boa), on exhibition at the museum in Beneath the Surface: X-rays of Arctic Fish. Image: Noel Alfonso, Roger Bull © Canadian Museum of Nature

Species discovery is a regular function of science experts who work at natural-history museums. Packaging their findings into books such as this one is a huge undertaking that stand as unique, valuable contributions for a long time. Sometimes the results of our research are used in playful, entertaining and artistic fashion, such as when the Museum of Nature turned Arctic fish X-rays into an art show in its Stone Wall Gallery. All part of our quest to connect people to nature.