Diving for Mermaids Purses in Zhemchug Canyon
by Jackie Dragon
July 14, 2012
Are you claustrophobic? I got that question a number of times when I told people I was being trained to pilot a tiny two-person submarine in preparation for Greenpeaces research exploration into the biggest underwater canyons on earth, out in the middle of the Bering Sea. I guess no is the answer. I just dove 840 feet down into Zhemchug Canyon in a little red submarine and if the smile I couldnt wipe off my face is any indication it was not a difficult experience at all.
I am not a scientist. But Margaret Mead once famously said: “Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has. That idea gave me my license to drive this little red submarine down into this Grand Canyon in the sea. For the past year I have been campaigning to get this spectacular Bering Sea feature submarine canyons like this one are rare and occur in only 4% of the worlds oceans and its slightly smaller sister, Pribilof Canyon, protection from fishing gear that sometimes plows through ripping up the golden habitat within.
Looking out over the gigantic canyon 60 miles wide and 9000 feet deep there is just blue water as far as you can see. But I was about to get a rare view of what lies beneath; this being the first submarine research ever conducted in this place. Unlike the wild and tumultuous Bering Sea I might expect the water was pure silk and calm, inviting me in for my first dive into deep water.
The Esperanzas crew hitched the crane to the sub and lifted us over the ships railing and down to the water for our launch. Bobbing at the surface, we enabled thrusters and moved away from the ship. This position gave an unexpected and delightful new view of the sea birds Id been photographing all morning on deck. As they floated around our sub, probably hoping we were food, we watched their webbed feet paddling beneath their round bird bellies in the crystal clear water. Think of the submarine dome as a giant scuba mask. When one took flight a perfect line of three inch bubble streaks pierced the waters surface just where their feet hit the water. And then it was time to flood the tanks and begin our descent.
Quickly the light of day disappeared and our eyes caught only the snowstorm of millions of tiny zooplankton the microscopic animals that nourish the rich canyon water column – and the neon splendor of jellyfish-like ctenophores floating gracefully past us on our way down. There is a reason the Bering Sea is the site of the biggest food fishery in the world. The shelf break where these enormous canyons cut into the slope are the source of nutrient-rich upwelling waters that draw a great array of wildlife. The waters are so productive that scientists call this stretch of water the Green Belt. And thats why we were diving in now, to bring back some more science to help make the case for conserving some of these most valuable places in the Bering Sea.
We reached the bottom and it was time to power up our high powered lights and camera equipped with indexing lasers. The video from our dives will be sent to scientists and each frame will be analyzed to give a precise understanding of the diversity, abundance and size of life here. This is a much more detailed method of observation than what can be gleaned from the trawl surveys conducted every other year by the Alaska Fishery Science Center. It didnt take long for me to realize the laymans answer to questions about these canyons: tons of life down here!
We flew or is it drive, I prefer flew the submarine forward slowly at about one knot speed, cruising just above the seabed. As far as our lights would illuminate the ground was carpeted with life: sponges, corals, anemones and sea stars. And among them, fish, swimming here, curled into a sponge there. It was a veritable cornucopia of life thriving in the dark, far from anyones sight until today. We encountered a cloud of fish, Pacific ocean perch. Then sponges in all shapes and sizes: tubes, funnels, encrusting, vases and barrels. Fern-like corals waved as we passed over. Next we were heading straight up, our submarine hugging the sheer rocky face of a pinnacle, like a diver carefully exploring a Caribbean reef wall, every inch populated with sea life.
We stopped to get a close-up of a boulder teaming with diverse organisms. John, my co-pilot and a marine biologist, reminded me that everything down here is an animal. Sponges and corals may seem very plant-like, but animals they are. And these animals are especially vulnerable to heavy fishing gear because they are long-lived and grow very slowly, only centimeters per year. Some are hundreds or even thousands of years old and when ripped from their seafloor holds they may never recover. When they are gone so is the habitat for so many marine animals, all part of the Bering Sea ecosystem and food web.
Resuming our dive, we proceeded slowly upslope on transect, the course that scientists will use to mark what we found. Suddenly I spotted a familiar sight: a skate egg case. Skates are similar to sting rays, and their eggs looks a bit bat-like, or like a small leathery brown purse with horns on each end. Skate egg cases are also called mermaids purses.
Recently at a North Pacific Fishery Management Council meeting, where Council members have been deliberating on a proposal to protect the six known skate nursery sites in the Bering Sea, Jerry Hoff, the lead Research Fisheries Biologist on skates passed around a small cardboard box full of mermaid purses for all of us to touch and see up close. I learned that skate embryos develop in these casings which are deposited in discrete places, known as nurseries, in the deep ocean, often near the slope edge of canyons where conditions are best for hatching. Due to cold temperatures the embryos take three to five years to emerge from the cases. As Jerry explained, scientists are just now beginning to understand where the nursery sites are and why skates lay their eggs in such specific places.
As we looked closer at the substrate coming into view we saw more of them, and skates too. We maneuvered a bit to the left and soon we were cruising over piles and piles of mermaids purses strewn across the dusty landscape. We found a new skate nursery! How do they know to come back here, John wondered across our submarine intercom. True enough, there looked to be thousands of skate eggs in the nursery, and scientists do know that skates come back to the same site generation after generation so only the egg cases on the tops of these mounds were likely filled with developing embryos. How do they know?
The canyons hold many mysteries still. Once we thought life required sunlight to exist. Nope. Unfortunately, we have invested much more energy into extracting from the deep ocean – the fish, food and profit – rather than working to understand how the ecology works down here. Without that we risk losing it all by fishing too hard and destroying the fragile coral and sponge habitat homes and nurseries for commercially valuable fish and crabs.
Unfortunately, last month the North Pacific Fishery Management Council decided not to conserve the six skate nursery sites they had learned so much about from Dr. Hoff and his colleagues. Instead they chose a lesser alternative that simply identifies the sites as Habitat Areas of Particular Concern and requires they be monitored for changes in egg density and other potential effects of fishing. The interests of industrial fishing fleets were put above all else, as is often the case here.
I believe we can strike a better balance. We should be able to protect a representative portion of our most productive and vital ocean ecosystems as an insurance policy for the future, and still catch fish by the tons, sustainably into to the future. Its unclear how long it will take until decision makers see how they can strike this balance, and it will probably take many thoughtful, committed citizens to help them find the way. Perhaps my journey down into Zhemchug Canyon and our discovery of a nursery there, full of mermaids purses, will help us get there.