Dominance and a large black manta ray

Location: Roca Partida, Revillagigedo Islands (Socorro Island), Mexico.

Comments: Wow! We had an incredible day of diving today. The seas around Roca Partida were almost flat calm, with just a very low swell from the northwest. It was very different than the challenging open ocean swell of yesterday. And the animals were amazing. Guests were really excited when they came back from their dives and were saying that this was some of the very best diving that they have ever experienced. Anywhere!! Anytime!! We had silky, silvertip, white tip reef and schooling hammerhead sharks. Wahoo. Tuna. A school of dorado so dense that the divers reported that the sun was blocked by all the fish above them. And, of course, the mantas.

Very friendly mantas. Mantas that we all loved. They are truly amazing animals. Interestingly, one group of divers reported observing behaviour that reminded me very much of the great white sharks of Guadalupe Island. Last season we would see 2 white sharks swim side-by-side as if they were measuring their respective lengths against each other. The smaller animal would then peel off into the blue. The larger animal presumably being the dominant animal. I “think” we saw the same thing with 2 giant manta rays. 2 animals (a chevron manta and a larger black manta) swam in tight formation in a vertical pattern. The smaller chevron then peeled off and disappeared into the blue. Presumably, just like the white sharks, the large black manta ray established it’s dominance and got to hang out with a human.

I spoiled myself by going freediving and had a tremendous time. It’s hard to beat the feeling of launching yourself down into the blue in the open ocean surrounded by all these neat critters. Especially when inquisitive white tip reef sharks come over to see what this particularly crazy human is doing! A couple of them came extremely close. Yes, I know they are harmless but still…..

Just to make our wonderful day that much more perfect, 2 humpback whales decided to breach, and breach, and breach 150 metres away from the Nautilus Explorer during our lunch break. These were exceptionally considerate humpbacks as they positioned themselves perfectly so that our guests could both enjoy their lunch and watch the show out the dining room windows. Safe diving.

–Captain Mike


Weather: Small fluffy scattered cumulous cloud, calm seas, no wind, 77°F.

Water: Water temperature 73°F, visibility 100 feet.