defending the deep
by John Hocevar
August 15, 2007
Greetings from Unalaska/Dutch Harbor, in the Aleutian Islands. We have finished our (first!) submarine expedition to explore two of the world’s largest underwater canyons. The crew is tired but happy, and so am I. The weather cooperated, and we were able to do 25 sub dives and 8 successful ROV dives, giving us well over 50 hours on the bottom. From the techical and logistics side, the expedition was a huge success. But what did we find, and what does it mean?
Above all, these are patchy environments, with rocky areas scattered throughout what otherwise tends to be fairly silty. While it was clear from the amount of holes, mounds, and tubes that there was a lot going on below the sediment throughout the canyons, the larger creatures tended to be associated with hard substrate. This often came in the form of drop stones, rocks that fell from melting or shifting ice bergs, which provided a base for corals, sponges, hydroids, anemones, bryozoans, and other important habitat-forming invertebrates. These areas were almost always home to fish and crab.
We found about ten species of corals and an even greater diversity of sponges, including at least one that is likely to be a new species. We collected dozens of specimens, several of which may be new species as well. This is not surprising, given how little is known about these canyons. Even this expedition has just barely scratched the surface when it comes to truly understanding the canyons.
Some of what we found was beautiful and exotic. It was a real treat to watch a giant octopus walk across the seafloor, to see tiny snail fish larva hatch from the eggs that had been deposited in a sponge, and to visit places never before seen by human eyes.
And some things were not so beautiful. We all knew, intellectually, that much of the Bering Sea has been heavily trawled. Still, I don’t think any of us were prepared for how widespread the damage is in these deep, remote areas. We saw trawler tracks on most of our dives, and sometimes it seemed as if the tracks were everywhere. On one of my dives, I passed through a large area where nearly ever coral I saw was broken or knocked over.
Now it is time for us to take this information to the scientists and policy makers at NOAA Fisheries and the North Pacific Fishery Management Council. Based on our findings here, it is clear that continuing to allow trawl gear to impact the seafloor in the canyons is not an option. In order to protect the corals and sponges that provide habitat for fish and crab, and in order to protect the yet to be discovered deep sea life found in the depths of these canyons, we need to act now.
Of course, it’s not going to be that simple. While some fishermen are clearly committed to science-based solutions to ensure that critical habitats are protected and fisheries are managed sustainably, others will fight us tooth and nail. We have truth on our side, though, and truth when backed up by determination, we’ve got for sure, will win in the end.
Thank you for coming along with me for this wondrous expedition. George is back on board now to continue our work with native communities, so keep in touch for more updates from him.
For the oceans,