NOAA Teacher at Sea
Lacee Sherman
Aboard NOAA Ship Oscar Dyson
June 6, 2018 – June 28, 2018
Mission: Eastern Bering Sea Pollock Acoustic Trawl Survey
Geographic Area of Cruise: Eastern Bering Sea
Date: June 8, 2018
Weather Data from the Bridge on 6/9/18 at 17:00
Latitude: 55° 34.3 N
Longitude: 162° 39.0 W
Sea Wave Height: 2-3 ft
Wind Speed: 12 knots
Wind Direction: 335° NW
Visibility: 8 knots
Air Temperature: 7.1° C
Water Temperature: 8.6° C
Sky: Blue with scattered clouds
Science and Technology Log
On Wednesday, June 6th 2018, NOAA Ship Oscar Dyson left port from Dutch Harbor Alaska at 08:00 to go and fuel up for the upcoming voyage. Fueling the ship takes hours and during that time, NOAA Ship Oscar Dyson took on over 50,000 gallons of fuel. After the ship was fueled, it searched for a spot in Captain’s Bay to calibrate the acoustic equipment. In order to calibrate the equipment, a metal ball made of tungsten carbide was suspended beneath the boat under the center board. The ball has known acoustic return values based on density and purity of the metal. It is attached at three points to the boat so that it can be moved under the center board to calibrate each transducer.. The location of the ball is adjusted under each transducer one at a time to the center of each beam. Adjustments to the equipment will be made if the return from the ball at each transducer is not as it is expected to be. The scientists had to change the depth of the ball in the water in order to avoid the fish to get an accurate reading. The calibration can be different depending on the temperature of the water and the salinity (saltiness) of the ocean. A second calibration will be taken at the end of the research cruise and the average will be used in the necessary calculations. Once calibration was complete and the equipment was retrieved, the ship started heading to the beginning location of the first transect line.
The journey from our calibration point to the start of the first transect line took approximately 23 hours, traveling at 12-13 knots. The ship reached the northern end of the first transect line at approximately 21:00 (9 pm) on June 7th. The first trawl sample was taken shortly after at sunset, which was approximately 23:30 (11:30 pm). This is not an ideal time to collect a trawl sample though since the fish move and behave differently at night. The first trawl sample of the survey that I participated in was on 6/8/18 at approximately 15:30.
Operations on the ship run 24 hours a day, so some members of each team onboard need to be awake and working at all times. Shifts for the science team are 12 hours long and the day shift runs from 04:00 (4 am) to 16:00 (4 pm) and the night shift is from 16:00 (4 pm) to 04:00 (4 am). I am assigned to the day shift along with Chief Scientist Denise McKelvey and Fisheries Biologists Sarah Stienessen, Mike Levine, and Scott Furnish. On the night shift for the science team are Nate Lauffenburger, Darin Jones and Matthew Phillips.
In order to collect a trawl sample, members of basically every department on the ship are involved. The NOAA Corps officers are on the Bridge driving the ship, charting the course that the ship will be traveling on as it collects it’s samples, as well as keeping track of the net, and all of the other duties that they regularly hold. The stewards keep us all fed and happy. The deck crew are in charge of making sure that all of the nets are hooked up properly and are put into the water correctly as well as controlling the winches that release the nets. The engineers make sure that all equipment is functioning properly. The survey technicians ensure that all of the scientific instruments used for making any type of measurements are attached to the net at different points, mainly on the kite. The “kite” is a section of the net primarily used for holding scientific instruments. Some of the scientists are preparing the fish lab and getting dressed in waterproof gear, while the Chief Scientist is on the Bridge with the officers giving direction about where and when to start and stop trawling and exactly how deep the nets should be set. Adjustments to the net are regularly made during the sample collection.
The locations for when trawl samples will be collected is not pre-determined before the start of the research cruise. The sites for samples are determined in real time by looking at the data collected from the acoustic pings being sent out by the transducers. There are 5 different frequencies( measured in kilohertz) sent out by the ship’s transducers: 18 kHz, 38kHz, 70 kHz, 120 kHz, and 200 kHz. The acoustic frequency that may best indicate the presence of pollock is 38 kHz. The chief scientist decides when she wants to “go fishing” based off of looking at the results coming back as echoes to the ship.
On this leg of the research cruise thus far, 3 trawl samples have been collected from the transect lines. I will include more detailed information and photos of the fish processing protocol in my next blog. In the next three pictures, there are temperature and depth profiles of our sample collection. The depth (in meters) is shown by the shape of the line as it rises and falls, and the color shows the temperature (in degrees Celsius) that goes with the scale on the right of each figure. More specific details are underneath each image.
Personal Log
Now that the ship is in the middle of the Bering Sea and is moving, I have learned an important lesson: You can’t trust the floor. I know that sounds weird, but usually you know exactly where the floor is going to be when you are walking, but when the ship is moving in the water, the floor may be higher or lower than expected, causing a lot of wobbling. This is especially challenging for someone who is as naturally clumsy as I am. There are times when I feel like a toddler learning to walk again, but I am getting more and more used to it already. At night it feels like being gently rocked to sleep.
I’m learning my way around the ship and I am starting to not walk right past the doors that I need to go into a few times before I remember that it’s the right place. I am also getting more familiar with the people onboard as well as the schedule. Since my shift that I am working on is from 04:00 (4 am) to 16:00 (4 pm), it took a few days for me to adjust and everyone was very patient with me. Coffee definitely helps! The meal times are as follows: Breakfast 07:00, Lunch 11:00, Dinner 17:00 and there are always some snacks available in the Galley.
In my downtime on the ship, I have found a new favorite location; the flying bridge! The flying bridge is located above the Bridge (where the Ship is controlled). There is a chair up there that makes the perfect spot on a nice day to sit and read for a little while. It is windy and cold, but worth it! The view from up there is pretty amazing!
Did You Know?
The NOAA Commissioned Officer Corps is one of the 7 uniformed services in the United States. The other 6 include: Army, Marine Corps, Navy, Airforce, Coast Guard, and the Public Health Service Commissioned Corps.
Math Challenges!!!!
If the Dyson regularly travels at 12.5 knots, how many miles per hour is it going? (Hint: you may want to look at my previous blog before you try this.)
Currently 9 of the people aboard the NOAA Ship Oscar Dyson are women. If there are 31 total people on the ship, what percentage of them are women?
