Scaling Submerged Mountains
September 1-4, 2000

	Sunset Photograph by Gale Mead

Departing Key West the evening of the second, we quite literally sailed off into the sunset, and what a sunset! Key West’s sunsets are legendary, and as the Gordon Gunter made its way west to the Dry Tortugas, it was easy to see why.

For this leg of our journey, we are joined by several members of the Florida Keys National Marine Sanctuary staff, including Mary Tagliareni, Dave Savage, and John Hollis. Mary and Dave will be piloting the sub to obtain information about the habitats and fish that are a part of the sanctuary they are charged with protecting, while John helps out with swimmer duties during sub ops.

Also aboard are two videographers from National Geographic Television, Bill Mills, and Darren Tedder. Their job will be to shoot a program about Sylvia, and our mission here, for the soon-to-be-launched U.S. National Geographic cable channel. Over the next week, we will all become very accustomed to Darren’s fuzzy boom mike over our heads, and Bill’s camera pointed at us whether we’re prediving or launching the subs, discussing our dive plans, or doing our mending!

	Mark Miller Photograph by Gale Mead

Before pulling into Key West a few days ago, Sylvia did an exploratory dive south of Riley’s Hump in an area we named Mark Miller’s Mountain in honor of the Gunter officer who found this dramatic rocky feature. Our first priority on this leg of our journey is to further explore this previously unknown, and biologically rich, undersea ridgeline. The ridge itself extends east and west for miles. We are focusing on a section on the western edge of a proposed no-take zone, where protections are slated to take effect a few months from now. It will be interesting to compare areas within and outside this reserve after a few years of such protection.

As I descend for my morning dive on Miller’s Mountain, I find visibility quickly decreasing. Touching bottom at 380 feet [116 meters], I can see perhaps 20 feet [6 meters], dimly, though the gloom. I am at the foot of the “mountain,” in an area of rocky rubble and great narrow pinnacles 10-15 feet [3-4 meters] high, and no more than that in circumference. Grouper and snapper mill about smartly just out of range of the sub’s high intensity lights.

Still at my initial touchdown site, I turn the sub to take a good first look around at the pinnacles around me. What I see makes my heart skip a beat, and I heave a sigh for my good luck in not coming down between the two pinnacles just behind me. Draped from the top of one to that of another 25 feet [7.6 meters] away, a knotted snarl of rope lost by some long-ago fisherman could easily have become entangled in the sub’s thrusters had I come down on top of it.

After a brief exploration to 405 feet [123 meters] on the deep side of the slope, I begin my climb up the steep 60 degree underwater hillside, pausing along the way to film pencil urchins, fish, cup corals, and crinoids. Nearing the top of the rubble- and boulder-strewn slope, I begin to see vertical rock formations reminiscent of the blocky ledges and cave-pocked walls of north Pulley Ridge. At 270 feet [82 meters], the depth is about what we would expect for these types of rock formations, part of a 10,000 year old shoreline.

Nearing the top, I find something that we will see all too commonly during our time in the Tortugas: An abandoned fish trap, its age hinted at by the many growths encrusting its wire mesh. Indiscriminate killers, fish traps take not only the target species but many other fish as well. Ghost traps like this one can sit on the bottom for years or even decades, continuing to kill any creature unfortunate enough to enter its one-way portal.

Just beyond the 10-20 foot [3-6 meter] vertical ridgeline that marks the top of Miller’s Mountain, rocky mounds riddled with caves and hidey holes offer the perfect habitat for yellow mouth grouper, bank butterflyfish, and blue angelfish, bigeye, damselfish, and many others. Perched on the edge of the chasm, I soon find myself surrounded by a school of the largest amberjack we’ve yet seen, up to four feet [one meter] in length. I spend the next 20 minutes reveling in their beautiful display. Above and around and in front of me, then down into the abyss and back up again over the lip of the dropoff, their movements are mesmerizing.

Throughout the next few days, we dive on portions of this ledge several times more, including a dual sub dive in which Sylvia and I are able to explore together this beautiful and productive place. Highlights include a moray eel lurking midslope at 350 feet [106 meters], a field crowded with pencil urchins, basket stars gracefully unfurling their long branching arms for nighttime feeding, and many more amberjack, snapper, and grouper.

Dave Savage completes a dive on the same ledge two miles [three kilometers] to the east, outside the boundary of the proposed reserve, thus establishing a comparison site for the effectiveness of the no-take zone. He finds a zone just as lush with fish and invertebrate life. The presence of lots of large snapper, grouper, and amberjack is cause for celebration. Calling to topside over the underwater telephone, he reports the sub surrounded by blackfin tuna, butterflyfish, and black grouper, and the same type of habitat seen further to the west.

—Gale Mead
Sustainable Seas Expeditions

[Note: nationalgeographic.com does not research or copyedit dispatches.]