3 months ago

AD 2016 Q4

Alert Diver is the dive industry’s leading publication. Featuring DAN’s core content of dive safety, research, education and medical information, each issue is a must-read reference, archived and shared by passionate scuba enthusiasts. In addition, Alert Diver showcases fascinating dive destinations and marine environmental topics through images from the world’s greatest underwater photographers and stories from the most experienced and eloquent dive journalists in the business.


IMAGING SHOOTER COCONUT OCTOPUS IN A GUINNESS GLASS “Every night dive delivers the unexpected, sometimes in weird or funny ways. In Lembeh Strait, Indonesia, we came across a coconut octopus dragging its mobile home — a discarded Guinness glass — across the nondescript muck of one of the dive sites. When caught in the dive torch’s beam, the octopus retreated into the relative safety of the transparent glass, perhaps overlooking the fact that it was hiding in plain sight. Working for a UK dive magazine and having attended staff debriefings in a pub or two, I thought it seemed appropriate, perhaps even destined, for DIVE’s readership.” LEAF SCORPIONFISH BY DAY AND NIGHT “At one island we visited in Cenderawasih Bay, Indonesia, there was an abundance of leaf scorpionfish (Taenianotus triacanthus), cryptic yet fascinating ambush predators that are often found in pairs or trios. They remain resident at specific coral formations for months or years and can be found in various colorations (for reasons unknown) ranging from pale white to gold to magenta to dark brown. I made the image of a striking magenta specimen on a morning dive and returned to the same reef for our night dive. Instead of using a typical dive light during the night dive, I used Nightsea fluorescence excitation lights and a filter to capture the bioluminescence given off by many coral species as they feed at night. As I shined the blue light of my Nightsea torch into the darkness, the dazzling glow of the same leaf scorpionfish stood out in the darkness from 15 feet away. The orange glow comes from a bioluminescent bacteria associated with the scorpionfish’s skin. A companion leaf scorpionfish, which was brown during the day, gave off no bioluminescent glow by night. The bioluminescent glow is believed to be visible to other fish, but the purpose it serves in unknown.” 96 | FALL 2016

THREE-SPOT FROGFISH “Masters of camouflage, frogfish play the waiting game, ultimately prevailing as ambush predators par excellence. Their ventral fins are modified for grasping like hands, and they’re content to sit motionless for long periods of time. They use another modified fin that they manipulate to move and wiggle like live bait on a fishing rod, luring a feckless fish within swallowing distance of a cavernous mouth. This three-spot frogfish, photographed in the Philippines, has coloration that blends with the reef and is augmented by algal growth, making detection of the frogfish quite difficult, even for seasoned spotters.” SNAPPER AGGREGATION “French Polynesia is one of my favorite places in the world, and my best dives there have consistently been in the Tuamotu Islands. Normally when one thinks of the Tuamotus, one thinks of sharks. Sharks there are (aplenty), but there is so much more. Visiting Rangiroa at different times of the year will reveal different phenomena. In October, the outside reef and Tiputa Pass are filled with a spawning aggregation of humpback snappers (Lutjanus gibbus). The number of fish must reach into the hundreds of thousands if not millions. The reef is barely visible through the mass of fish.” ALERTDIVER.COM | 97