Day Four – Epic currents (Kirby’s Rock)
We finally found our first deep, clean water – clean because the area is a washing machine of currents spilling through the Verde Island passage. Over the course of our descent and ascent, we had, in order, a strong down current, a left to right mild current switching to a screaming right to left current, and then a quite strong up current on ascent. So strong, that Richard in the lead couldn’t come down to me (20 feet lower), to try to collect a new sand perch that we have been seeing deep across this area of the Pacific.
Currents are generally to be avoided for the style of diving we are doing; drop in the shallows, check gear, and navigate generally straight down the slope looking for reefs and structure among the sand/silt and rubbish. After some lateral movement at depth, we try to come back up the same general path we took down, to allow us to find the boat easily. Cross currents obviously can throw off our navigation in both directions. Up and down currents can be a little more insidious, either pushing us deeper than we want to go or hindering our return to the surface, or in the case of an up current, make our safety stops to decompress more difficult to hold. The benefit of this current turbulent site, was the cleanest water we have seen, clearing the silt and sand, revealing excellent tall boulders with under-hangs, full of deep reef fishes.
We collected a number of beautiful anthias and damsels, and recorded a rich population of deep sea fans.
Additionally, I collected a beautiful white and black nudibranch at 90m, that may be new to science, or if a known species would be the first time it has been imaged alive. We will definitely return to this site, as we saw during the deep phase of ascent, large walls and structure around 80-90m that were teeming with clouds of fish.
Descent and ascent was also unique to me, in that the thermoclines we typically encounter were multiple and not necessarily in descending order. A distinct line of much colder water is generally a good
indication that we have passed through a “faunal shift” to new habitat as we descend. The more layers the better, as certain deep fishes prefer the colder tropical water habitat. In today’s case, we sometimes would enter a cooler water band and then a much warmer band deeper and then another cold band. An oceanographer would probably have a field day determining the cause of such turbulent, mixing conditions – conditions that made for an exciting, dynamic dive.
Decompression for this type of dive is generally around 2.5-3.5 hours, which is a perfect opportunity to search out interesting fish and film them, taking the deliberate steps to get good images, rather than the smash and grab techniques used deep where minutes are precious. Folks on expedition always like to see pictures of “pretty fish” – I guess not everyone can get excited about a new, drab, darting fish, just because it is new. Clownfish in anemones, clown triggerfish, butterfly and angel fish abound throughout the shallows in Anilao, and make for “the pretty picture”.