This is very cool but I'm a bit confused by what the depths represent - is it minimum depth you need to get down to before you start seeing the animal, is it th

This is very cool but I'm a bit confused by what the depths represent - is it minimum depth you need to get down to before you start seeing the animal, is it the average depth that animal lives at? I've seen Giant Pacific Octopus diving around 20m, but this visualization lists them at 770m. Still very cool, and I love how it is searchable in plain text (eg. I can ctrl + f and type octopus and it takes me directly to the correct depth)