NOAA Teacher at Sea
Aboard NOAA Ship Oscar Dyson
July 26 – August 13, 2014
Mission: Walleye Pollock Survey
Geographical Location: Bering Sea
Date: August 4, 2014
Weather information from the Bridge:
Air Temperature: 11° C
Wind Speed: 8.95 knots
Wind Direction: 327°
Weather Conditions: Foggy
Latitude: 58° 59’92 N
Longitude: 176° 55’09 W
Science and Technology Log:
Now that we have chosen a location to fish, the real fun begins! With a flurry of action, the Bridge (control center of the ship) announces we are going to trawl (fish). This alerts the Deck Crew who has the responsibility of deploying a net. There are three different types of trawls, AWT (Aleutian Wing Trawl), 83-112 Bottom Trawl, and the Marinovich. The type of trawl chosen depends on the depth in the water column and proximity to the bottom of what we want to catch. The 83-112 Bottom Trawl pretty much does what it is called. It is drug along the bottom of the ocean floor and picks up all sorts of awesome sea creatures. The Marinovich is a smaller net that is trawled near the surface. For this Pollock survey, we have primarily used the AWT. It is a mid-water net and that is the area where Pollock primarily live.
As you can see in the diagram, the AWT is cone-shaped. When fully deployed it is 491 feet long! The opening of the net, similar to a mouth, is about 115 feet wide. The Chief Boatswain (pronounced bo-sun) controls the winches that let wire out which extends the opening of the net at least another 500 feet from the aft (rear) deck of the ship.
The Deck Crew begins to roll out the net and prepares it for deployment. There are several pieces of equipment attached along the way. A Camtrawl is attached first. Can you guess what it does? It is essentially a camera attached to the net that records what is being caught in the net. Near the Camtrawl, a pocket net is attached to the bottom side of the AWT. This pocket net can show scientists what, if any, fish are escaping the AWT. On a piece of net called the kite that is attached to the headrope (top of the mouth/opening), the FS70 and SBE are attached. The FS70 is a transducer that reports data to the Bridge showing the scientist what is coming into the net, similar to a fish finder. The SBE is bathythermograph that records water temperature and depth. Tomweights are added next. These heavy pieces of chain help weigh the footrope (bottom of the mouth/opening) down, pulling it deeper into the water. The net continues to be reeled out and is finally connected to lines on each side of the deck. The horizontal distance between the lines helps the net to fully open its mouth.
While the net is out the Bridge crew, the Chief Boatswain, the Survey Tech and at least one scientist are on the Bridge communicating. Each person has a role to ensure a successful catch. The Bridge crew controls the speed and direction of the boat. The Chief Boatswain controls the net; changing the distance it is deployed. The Survey Tech has information to report on one of the computers. Lastly, the scientist watches multiple screens, making the decision on how far out the net goes and when to haulback (brings the net in). Ultimately, the Bridge crew is the liaison between all of the other departments and has the final decision on each step of the process, keeping everyone’s safety in mind. This piece of the fishing puzzle quickly became my favorite part of the survey. It is so neat to listen to the chatter of all these groups coming together for one purpose.
Once we have reached haulback the Chief Boatswain alerts his deck crew and they begin reeling the net back in. They watch to make sure the lines are going back on the reel evenly. When the tomweights come back on deck they are removed. The next items to arrive are the FS70 and SBE. They are removed and the reeling in continues. The Camtrawl comes in and is removed and the pocket net is checked for fish. By that point we are almost to the end of the net where we’ll find our catch. Because the net is very heavy, the deck crew uses a crane to lift it and move it over the table. A member of the Deck Crew pulls a rope and all the fish are released onto the table. The table is a piece of equipment that holds the fish on the deck but feeds them into the Wet Lab by conveyor belt. Once the fish have been removed from the net it is finally rolled up onto the reel and awaits its next deployment. In my next blog we’ll get fishy as we explore the Wet Lab!
I have delayed writing about this next location on the ship because it is my favorite place and I want to make sure I do it justice. Plus, the Officers who stand watch on the Bridge are really awesome and I don’t want to disappoint them with my lack of understanding. Here are a few pictures showing some of the things I actually do understand…
This screen provides Officers with valuable information about the ship’s engine, among other things. This diagram shows multiple tanks located on the ship. Some tanks take in seawater as we use diesel fuel, drinking water, etc. to counter balance that usage and keep the Dyson in a state of equilibrium. Also, if they are expecting high seas they may take in some of the seawater to make our ship heavier, reducing the effects of the waves on the ship. I’ve been told this may be important in a couple of days because we’re expecting some “weather.” That makes me a little nervous!
The General Alarm is really important to the safety of all those on the ship but it is not my favorite thing every day at noon. The General Alarm is used to signal us in an emergency – Abandon Ship, Man Overboard, Fire, etc. It is tested every day at noon…while I’m sleeping!! “Attention on the Dyson, this is a test of the ship’s General Alarm.” BEEEP. “That concludes the test of the ship’s General Alarm. Please heed all further alarms.”
What would happen if all of our fancy technology failed on us? How would we know where to tell the Coast Guard to find us? NOAA Corps Officers maintain paper charts as a back up method. At the time this photo was taken the Officer was predicting our location in 30 minutes and in 60 minutes. This prediction is updated at regular intervals so that we have a general area to report in the case of an emergency. Officer Gilman completes this task during his shift.
Have I mentioned that the NOAA Corps Officers onboard the Dyson are awesome? They’re so great they let me steer the boat for a little while! In the photo Lt. Ostapenko teaches me how to maintain the ship in a constant direction. The wheel is very sensitive and it took some time to adjust to amount of effort it takes to turn left or right. We’re talking fingertip pushes! The rudder is so large that even just a little push left or right can make a huge difference in the ships course.
Since beginning our survey I’ve only missed being on the Bridge for one trawl. Because I have paid very close attention during those trawls Scientist Darin is now allowing me to record some data. I am entering information about the net in this photo. Survey Tech Allen is making sure I do it correctly!
There are so many other things on the Bridge that deserve to be showcased. The ship can be controlled from any one of four locations. Besides the main control center at the front of the Bridge, there are control stations on either side of the ship, port and starboard, as well as the aft (rear). There is the radar system, too. It is necessary so the Officers can determine the location of other vessels and the direction they are traveling. As I’ve been told, their #1 job responsibility is to look out the windows and make sure we don’t run into anything. They are self-proclaimed nerds about safety and that makes me feel very safe!
Did you know? The NOAA Commissioned Officers Corps is one of the seven uniformed services of the United States. There are currently 321 commissioned officers.