OceanGate Blog Post

Possession Sound Shark Research Dives

By: Mikayla Monroe
July 16, 2019

By living deep in the ocean, sixgill sharks (Hexanchus griseus) have been able to well-outlast two mass extinctions. Their primitive features have helped them persevere for over 200 million years and be one of the widest-ranging sharks. While we’re both grateful and in awe of their survival, very little is actually known about these modern-day dinosaurs. And, no matter how hard we try, our “Follow” request seems to get lost in their inbox.

In the Salish Sea, scientists at the Seattle Aquarium, NOAA, and Washington Department of Fish and Wildlife joined forces to find out more about these elusive sharks. When researchers tracked the shark’s movements, they found that the sharks didn’t travel far from their home base in Elliot Bay, only making a vertical migration at night to hunt in shallower waters near the Aquarium’s pier. Then one day, they headed north up Puget Sound, took a left into the Strait of Juan de Fuca, and dove deep into the Pacific Ocean.

It was believed that Seattle’s local shark population were juveniles who had simply reached the point that they needed to leave the “nest” of Elliot Bay.

On their way out to the ocean, the juvenile sixgills passed through Central Puget Sound, which just so happens to be in OceanGate’s backyard. We have been diving every Tuesday and Thursday since mid-July in search of these hide-and-seek champions, working to establish a baseline understanding of the sixgill sharks in Possession Sound. We are looking to answer a couple of questions:

  1. Do they have similar demographics to those studied in Elliot Bay?
  2. Do the larger, mother sixgill sharks use Possession Sound as an escape from their wild teenagers?

Just like the Seattle Aquarium’s studies, OceanGate baits the water with salmon and halibut carcasses. Biodegradable burlap bags are filled with bait and weighted with rocks, then tied shut with biodegradable twine, and clipped to a buoy line that is attached to a bait box. We also mounted laser scalers to Cyclops 1 so that we can properly measure the sharks when we discover them.