Kirby's Rock

The rock you tie up beside is the small one. It breaks the surface, it looks like the whole site, and once you are under it turns out to be the peak of a much larger structure standing in deep blue water. A short swim leads to the second pinnacle, fully submerged, sloping away past anything a recreational tank will reach.

Between the two runs a canyon at twenty to thirty metres, and this is the sheltered half of the dive. Gorgonian fans grow along it, and Bargibant's pygmy seahorses live on the fans, found at twenty-seven and twenty-eight metres by divers working the site years apart. Current drops off inside the canyon and small animals collect there, so buoyancy costs more here than anywhere else on the rock.

The shoreward side is the other dive. The rock falls to five metres on that face and the reef slopes up towards the shore from there, with dense coral and crevices at the foot of the wall. Morays live in the crevices. Blue-ribbon, white-eyed, snowflake and zebra have all turned up in one dive, which is what a diver holding shallow above the canyon has time to look at properly.

Current is what makes any of it work. Fast, nutrient-carrying water sweeps the rock and the coral diversity follows it. The same water shifts direction partway through a dive and can run differently at each pinnacle, so the route you swim out is not always the route back.

A species was described new to science from this rock. Chromodoris alcalai Gosliner, 2021 has its type locality here, at a position printed in the description itself, and the holotype was collected on a scuba dive at 31.2 metres in March 20081. The species honours Dr Angel Alcala and his work on Philippine marine biodiversity. Until that paper it had been lumped in with Chromodoris dianae, whose own holotype came from Arthur's Rock across the strait, and paratype material for dianae had been collected on this rock too, at eighteen metres in 19941. Two nudibranchs that were one animal for twenty-seven years both have type material from here.

A type locality is a fact about taxonomy and not a sighting to plan around. The animal has type material from Tubbataha, Bohol, Cuyo and Okinawa as well, and no dive comes with it attached. What the same record does give is something no dive page normally has: nine dated collections from this one rock between 1992 and 2008, at eighteen, twenty-three, twenty-five and 31.2 metres1. That is a checkable account of where divers have actually worked the site, and it lands exactly on the band operators publish.

The animal you will see is a sea cucumber. Colochirus robustus is small, bright yellow and everywhere, thick enough on the mound to change the colour of the rock underneath it. Anthias hold station over the top in the flow. Whip corals grow out of the deeper faces with their resident shrimp, a giant frogfish has been photographed sitting out on a ledge, and so has a white leaf scorpionfish.

Anilao sells itself on sand and slow macro, and this is the counterweight. Divers who have spent a week on their knees over silt come here for the reef, and they come on the day the weather finally lets them.

Bring both lenses and decide in advance which tank gets which. Kirby's is run as a two-tank trip because of the crossing, so the surface interval is the natural place to change, macro first and wide-angle second.

Wide-angle is what the site is for, and wide-angle is the first thing unsettled water takes away. A week of wind leaves this water green even after the boats start running again, and green water on a reef this colourful wastes the crossing. Slack is the window that gives you the visibility and the stillness at once, so ask whether the boat is timed to it before you load a dome port.

The subjects are deep. Pygmy seahorses sit on fans at twenty-seven and twenty-eight metres, and the frogfish and the leaf scorpionfish both came off ledges. Working an animal two centimetres long at twenty-eight metres in current burns no-stop time fast, and the guides handle it by splitting the group and staggering the descent so the second half still has bottom time when it arrives. Expect to wait, and plan gas for the waiting.

Plan this one on the tide and not on the schedule. Slack water is what the site rewards, and it is why a shop will move Kirby's to another day. The other reason is the surface. An exposed rock in open strait comes off the plan first when it blows, and a week of wind can put it out of reach while the sheltered macro sites keep running normally.

Kirby's Rock carries no protection, and that is worth saying because several of its neighbours do. The no-fishing sanctuaries on this coast are Arthur's Rock, Twin Rocks, Cathedral Rock and Batalang Bato, and this rock is not among them. It was recommended as a good site for a no-fishing sanctuary and never designated as one2. Layag-Layag, the reef next to it, is recorded as encompassing the northern tip of Caban Island and Kirby Rock on the east2. The useful reading is a reef with a named feature at its eastern end. Layag-Layag is the reef, Kirby's is the rock, and they are dived as two dives.

Settle the depth before you get in. The recreational dive runs from about five metres on the shoreward reef to about forty at the base of the deeper pinnacle, and most of it happens between eighteen and thirty. The rock does not stop at forty. A vertical wall keeps falling below the deep rocks from roughly forty-five to eighty metres, carrying black and wire corals, and that eighty-metre figure is published in the same tables a recreational diver reads. It is trimix water and a different qualification, and it is not the dive you booked.

Carry an SMB and do not count on a line to come up on. Whether this rock has a mooring buoy is unresolved: anchor damage on this reef was recorded in 2011 and mooring buoys were called urgently needed at the time, and nothing since establishes what is in the water now2. Plan a free ascent in current with boats working overhead.

Then the part that is easiest to leave too late. No recompression chamber is confirmed operating in Anilao. The nearest one evidenced as working is in Metro Manila, roughly 140 kilometres and two and a half to three hours by road, and the road is only reached after a fifteen to thirty minute banca leg. This site adds about another twenty minutes, because the crossing back over the Maricaban Strait comes first. Hold insurance that pays for hyperbaric treatment and for the transfer, check the boat carries oxygen, and keep the DAN Asia-Pacific Diving Emergency Service number where you can find it: +61 8 8212 9242.