This may sound cynical. But, I sigh each time I hear of such natural discoveries. This basically means humans will begin interfering in the name of research.
Cephalopods will change a lot its length when tentacles are retracted (dead animal) or relaxed (alive), so 'mantle lenght' is used instead as a sort of equivalent to body length. Is a much less variable measure.
P.S. I feel the plural of octopus should be neither octopi nor octopuses, but either: octopus - same as singular, you know, like 'sheep'; octopussies - for fun, because they're not as cute as cats.
First of all the rocky botom can offer some kind of protection against trawls.
And second, is not clear if this octopus are edible. I can't identify the species with this video. Maybe Graneledone but I'm not sure. The much smaller squat lobster (Munida? Munidopsis?) in the video can be deceptive but the octopus look very small to me. We could be talking about a small animal of only 10cm of mantle length (body minus tentacles). Probably not valuable enough to risk the fishing material and spending fuel on it.