Life Aboard Ship, Dispatches From South of the "Roaring Forties"
Sunday, June 13, 2004
We're on our way to the South Sandwich Islands, or more precisely, Zavodovski Island, the northernmost of the chain. These are a very interesting group; they include eleven islands, eight of which are volcanically active. There are no human inhabitants, and on the east side, there is a trench that is about 8300 meters (26,975 ft.) at its deepest point. The association of volcanoes and oceanic trenches is well known; it composes the "Ring of Fire" around the northern Pacific and marks locations where the plates that form the surface of the earth meet.
South Georgia, although a very beautiful and interesting place, is (biologically) fairly well known. There is a very active commercial fishery there for several species. The South Sandwich Islands, on the other hand, are not nearly as well studied, so this will be interesting and exciting. In addition, during our transit we will pass over some fairly deep water (3000 to 3500 m or 9750 ft to 11,375 ft.) and will be surveying the bottom to see if it's flat enough to make a tow. I hope so! This is the Scotia Arc, however, and it is a region of geological activity (you can practically see it happening when you look at a chart of the area) so it won't be surprising if it turns out to be rough bottom. Of course, the shallow waters surrounding these islands are literally the slopes of active volcanoes, and so they are steep and rocky also.
Scientists have collected, studied and savored crabs collected during the ICEFISH cruise.
When we get to Zavodovski, we will be looking for relatively shallow water where we can make bottom trawls. The bathymetric charts are not very accurate for such remote regions, and we expect that those for Bouvetoya, the next island we will visit, will be even less useful. That means we will spend quite a bit of time surveying for good (that is "safe") spots where we won't lose the gear. It's made more difficult because we don't just need a single location, but a reasonably long track line in 100 m (325 ft.) of water, two miles at two knots (10 minutes for wire out, 30 minutes on the bottom, 10 minutes to retrieve). This is one reason why our benthic biologists have had so many samples on this cruise even when we don't catch fish or the bottom is not good and we tear up the net. They often get sponges and other bottom critters of interest to them. In some ways, successful biological oceanography is the ability to make the best of what you actually catch, not what you planned to catch! In places that are not thoroughly studied, you never know what's going to come up in the net (and even in well-studied places you are often surprised).
The weather has been unexpectedly good. Today, air temperature is below freezing at about 29° F, and water temperature is also below freezing (about 30° F), and it is foggy. There are a number of icebergs around us but they are invisible except of course to our radar.
It must have been really difficult for the early explorers to manage in these conditions. Imagine having to work the wet sails and rigging when it is below freezing, and avoiding icebergs and islands when visibility is less than 100 yards. Not to mention the general lack of heat on their ships and simply not knowing what to expect. It seems to me that we often forget how much we owe them, and how courageous they were. Our voyage would have seemed as unbelievable to them as theirs are to us, I'm sure.
Lobster krill, also called munid crabs, have been collected by the thousands.
Christoph Held is a German crustacean biologist from the University of Bochum in the Ruhr Valley of Germany. For him this has been a very successful cruise. We have collected tens of thousands of munid crabs, often called lobster krill, and dozens of larger crabs (genus Paralomis).
Christoph and his graduate student, Florian Leese, have looked at every one of them! They have counted and determined the sex of each, and in the case of the munid crabs, also collected a parasite that lives in their gill chamber. The parasites have also been counted and sexed. It is a huge amount of work, and much of it was conducted inside a cold room (basically, a refrigerator!). Christoph and Florian, using both the morphology (physical characteristics) and genetic characteristics of all of these crustaceans, are trying to determine the relationships between the different crab populations, and the frequency of occurrence of the munid parasites relative to sex and size of the individual. I am impressed.
The payoff for us fish guys is that they take the Paralomis to the galley when finished with them, and get the cook to make them for lunch or dinner. Although they do not have much meat, they are something different to eat (we are now out of most fruit, lettuce, cucumbers, and many fresh vegetables). We had a surprise hors d'oeuvre several days ago: crab caviar on crackers with guacamole or cream cheese. I ate some, and they were good, but not have too much flavor, and had a very nice crunch. There were not so many willing to sample them, though!