Of sharks, lights and lasers

To the shark obsessed, an opportunity to research bioluminescent sharks in your honours year is too good to pass up. Particularly when your research involves traveling to Norway doing fieldwork aboard a research vessel of Norway’s Institute of Marine Research. The end result was an amazing adventure, working with some great people amidst incredible scenery topped off in the end by witnessing the Northern Lights in their full awesomeness. The real aim of the trip was to research velvet belly lanternshark (Etmopterus spinax); these amazing little sharks glow in the dark at the depths they inhabit down to around 2,000 m and are listed as Near Threatened in the Northwest Atlantic due to fishing pressure. I collected vertebrae from specimens caught as bycatch during routine survey trawls and brought them back to Adelaide for laser ablation and chemical analysis (LA ICP-MS). My aim was to compare chemical signatures taken up from the water and stored in their vertebrae to see if sharks in southern Norway mixed with each other or with others in France, for which our French colleagues had donated samples. I found that most of those in southern Norway mixed, forming a single stock, whereas another population off western Norway was distinct and neither group mixed with the French sharks. This gives us an idea of the spatial scales at which velvet belly lanternsharks should be managed as separate stocks, so that they can keep glowing far into the future. If you would like to read more, you can find the newly published paper from this work here.

Images: Velvet belly lanternshark: https://owlcation.com/stem/What-Kind-of-Sharks-Live-in-British-Waters; Northern lights and field work in Norway images: Matt McMillan