NOAA Teacher at Sea
Aboard NOAA Ship Delaware II
August 8 – 19, 2011
Mission: Atlantic Surfclam and Ocean Quahog Survey
Geographical Area of Cruise: Northern Atlantic
Date: Wednesday, August 14, 2011
Location: 41°47N, 67°47W
Air Temp: 18°C (64°F)
Water Temp: 16.5°C (62°F)
Wind Direction: SE
Wind Speed: 6 knots
Sea Wave height: 0
Sea Swell: 0
Science and Technology Log
When I found out that the Teacher at Sea trip that I would be on was a clam survey, I thought, “Oh, clams. I see those on the beach all the time. No problem.” I learned that the clams are collected using a hydraulic dredge. I knew that a dredge was something that you dragged along the bottom of the ocean. That seemed simple enough. Drag it along, dump it out, count ‘em up, and you’re done.
Quickly, I learned that this project is not that simple! A few questions came to mind after we had done a couple of tows: How many people are needed to conduct one tow for clams and quahogs? (operate the machinery, the ship, sort through a tow, collect the data, etc.) How many different jobs are there during one tow?
Those questions are hard to answer, and I don’t have a precise answer. What I have learned is that it takes a lot of people and everyone that is involved has a job that is important. I asked the Chief Scientist, Victor Nordahl, how many people he preferred to have on a science team per watch. He told me that it is ideal to have six people dedicated to working on sorting the contents of the dredge, processing the catch, and collecting data per watch. Additionally, he likes to have one “floater,” who can be available to help during each watch. This seems like a lot of people, but, when there is a big catch this number of people makes the work much more manageable. There are six people, including myself, on my watch. Four of us are volunteers.
Each time the dredge is lowered, pulled along the ocean floor, and then brought back onto the ship it is called an “event.” In my last post I included a video of the dredge being hauled up onto the deck of the ship after it had been pulled along the bottom. An entire tow, or “event,” is no small feat! During my watch Rick operates the machinery that raises and lowers the dredge. (Don’t forget the dredge weighs 2500 pounds!)
There are also two people working on deck that assist him. (You can see them in the video from my last post. They are wearing hard hats and life vests.) Additionally, an officer on the bridge needs to be operating and navigating the ship during the entire event. There are specific times where they must speed up, slow down, and stop the ship during a tow. They also have to make sure that the ship is in the correct location because there are planned locations for each tow. Throughout the entire event the science team, deck crew, and the bridge crew communicate by radio.
As I said, this project is not simple! To make it more complicated, equipment often breaks, or is damaged, which means that the deck crew and the science team have to stop and fix it. On this trip we have stopped to fix equipment several times. Various parts of the dredge get bent and broken from rocks on the ocean floor. Before the dredge is lowered, the bottom is scouted with a depth sounder to try to avoid really rough terrain. On the screen of the depth sounder different substrates are shown in different colors. For example sand is shown in green and rocks are shown in red. We try to avoid a lot of rocks. However, all the rocks cannot be avoided and sometimes we hit them!
Before coming on this trip I was told that the work can be strenuous and, sure enough, it is. Sometimes a tow brings up hundreds of pounds of rocks (with some clams mixed in!) that we need to sort through and, as you know, rocks are heavy! The work is also a bit, well, gross. We have to measure all the clams, whole and broken and we also have to collect weights of “clam meat.” That means that we have to open the shells and scrape the meat out. I have a pretty high tolerance for gross things, but I am starting to grow weary of clam guts!
In between tows there is a little bit of down time to catch your breath, drink coffee and eat cookies, watch the ocean, and read a book. During one of these breaks, the Chief Scientist Victor Nordahl, took the moment and had his hair cut!