HURL 2002

Driving the Sub (9/13/02)
Posted by Rachel Shackelford

We've been out here for a few days now - starting to get the hang of the routine. Breakfast starts at 7:15. The sub goes in the water between 8:00 and 8:30. We have three sets of observers (a.k.a. fish counters), so after today each of them will have had a chance to test their skills at calling out the names of the fish that swim by the sub's portholes.

Once the sub reaches the bottom, the routine is that they will do three 30-minute transects, each at different depths, and two 30 minute bait stations. During each transect, the sub moves in a straight line while the observers count all the fish they see. There are three 6-inch portholes (a.k.a. windows) in the sub; the pilot uses the middle one to see where he is going and the two observers use the ones on either side of him. For half an hour, each observer must press their forehead up against the porthole and call out how many of each type of fish and invertebrates that they see. One person might say, "4 onaga, 2 ehu, one seastar with yellow tips" then as soon as he pauses the other observer would jump in and say, "3 kahala, 5 maunaloae, 2 Grammatonodus laysanus." Although the observers memorize the scientific names of all the fish and inverts that they are likely to see, it can be hard to spit out those long convoluted names all in a row. So sometimes they use the Hawaiian or common name for the fish and sometimes they call it by either its genus or species name. The main thing is that they must call it by a unique name that should be obvious to the person that will have to log the videotape. This audio record comprises the primary data that comes out of these fish transects.

In between the transects, they find a good rocky place that is not too steep where the sub pilot breaks open a bag of bait, backs the sub off a bit, and turns off the lights. Not very much light makes it down to 200 or 300 meters (over 600 and 900 feet, respectively), and the little bit of light that does make it down there is blue. With the lights turned off everything that previously looked red, orange, or yellow appears to be black. A low-light CCD black & white camera mounted on the sub captures the natural behavior of the fish under natural light conditions.

The sub pilot aims to leave the bottom by 4:00 pm and it is often hard for the observers to get all their work done in that time. They have done pretty well so far, though.