NOAA Teacher at Sea
Cristina Veresan
Aboard NOAA Ship Oscar Dyson
July 28 – August 16, 2015
Mission: Walleye Pollock Acoustic-Trawl survey
Geographical area of cruise: Gulf of Alaska
Date: Saturday, August 1, 2015
Data from the Bridge:
Latitude: 58° 39.0′ N
Longitude: 148° 045.8′ W
Sky: Broken clouds
Visibility: 10 miles
Wind Direction: W
Wind speed: 15 knots
Sea Wave Height: 3 feet
Swell Wave: 0 feet
Sea Water Temperature: 15.4° C
Dry Temperature: 13.8° C
Science and Technology Log
So, you might be wondering how our scientists know when it’s time to “go fishin’”? That is, how do they determine if there might be a significant concentration of pollock to deploy a trawl? The answer is acoustics! The ship is equipped with a multitude of acoustic transducers on the bottom of the ship, five of which are primarily used in the pollock population assessment. These transducers both send and receive energy waves; they transmit sound waves down to the ocean floor, which reflect back to the ship. However, if there are obstacles of a different density in the water (like fish), the signal bounces back from that obstacle. The amount of energy that pollock individuals of different lengths return is known to our scientists.
The real-time data from transducers is automatically graphed in what is called an echogram. When we are on our predetermined transect line, the scientist on watch analyzes the echograms to make the determination of when to trawl. The transducers are different frequencies. In general, the higher the frequency, the smaller the object it can detect. To make a final decision on fishing, the scientist must also coordinate with the officers on the bridge who take into account wind speed, wind direction, water currents, and ship traffic. Once we collect the trawl data, scientists use the catch information to assign a species and length designation to the echogram data in order to produce a pollock biomass or abundance estimate. In addition to the pollock we are targeting, we have caught salmon, cod, jellyfish, and a few different types of rockfish.
We often catch one type of rockfish, the Pacific Ocean perch (Sebastes alutus), which has a similar acoustic signature as pollock. On the ship, we call this fish POP, and they are difficult to handle because of the sharp spines on their dorsal fin, anal fin, head, and gill covers (operculum). You have to watch out for spine pricks when handling them! Their eyes usually bulge when they come up from depth quickly and gases escape, which is a form of barotrauma. One interesting fact about Pacific Ocean perch is that they are viviparous (give birth to live young); the male fish inserts sperm into the female fish and her egg is fertilized inside her body. These fish can also be incredibly long-lived, with individuals in Alaska reaching almost 100 years old. The Pacific Ocean perch fishery declined in the 1960’s-1970’s due to overfishing, but has since recovered due to increased regulation.
Shipmate Spotlight: Interview with Allen Smith
What is your position on the Oscar Dyson?
I am the Senior Survey Technician. It’s my second season in this role.
Where did you go to school?
There is no formal training for this position, but you do need a scientific/technical background. I have a BS in geology, and right after college, I worked in technical support for Apple.
What do you enjoy the most about your work?
My favorite part is meeting people and re-connecting with ones I already know. Different scientists rotate in and out and they are my contact with the outside world.
Have you had much experience at sea?
I have worked on ships since 2011. I worked on cruise ship as a cook then I joined NOAA and sailed on the NOAA ship Oscar Elton Sette in Hawai’i as a cook and then later joined the NOAA ship Oscar Dyson as a survey tech. I really wanted to get back into science so I made the switch.
Where do you do most of your work aboard the ship? What do you do?
The domain of the survey technician is the laboratory. We have wet, dry, chemical, and computer/electronics labs aboard the Oscar Dyson. I am responsible for the meteorological, oceanographic, and navigation data that the ship collects full-time. We also help visiting scientists to accomplish their missions using the ship’s resources, like deploying fishing gear, CTD, cameras, or other equipment. Sometimes we do special missions like last year when we went to the Bering Sea for an ice-associated seal survey and our ship had to break through sea ice. During scientific operations, I work a 12-hour shift everyday.
When did you know you wanted to pursue a marine career?
I grew up in Dallas, Texas, which is totally land-locked, so you could say I wanted a change.
What are your hobbies?
No time for hobbies at sea! Just kidding, I like photography and playing guitar and ukulele. When I am not at sea, I enjoy hiking and biking.
What do you miss most while working at sea?
Probably what I miss the most is being able to cook vegetarian meals for myself.
What is your favorite marine creature?
The red-footed booby because they have so much personality and are very entertaining.
Inside the Oscar Dyson: The Galley
The galley is ship-speak for the kitchen and dining area. Our ship stewards (chefs) work really hard to prepare buffet-style meals three times a day. Breakfast is served from 7-8am, lunch from 11am-noon, and dinner from 5-6pm. There is also a salad bar and a soup available for lunch and dinner. One night we even had food popular in Hawai’i: Kalua Pork, ramen stir fry, and chicken katsu! You can also come in the galley 24 hours a day to get coffee, espresso, tea, water, and various snacks. There is even an ice cream freezer! You might notice the chairs in the galley have tennis balls on the ends of the legs, as well as tie downs attached to them; this is to prevent sliding during rough seas.
Personal Log
One of the challenges of working on a moving platform is seasickness. Nausea can be really debilitating, and it prevents many people from enjoying time on the water. I am not prone to it, but I am aware it could still afflict me at any time. Luckily, we have had very calm seas, and I have felt great, even when typing on the computer or slicing up fish! I brought some anti-seasickness medication with me but I have not needed it yet. I also have some candied ginger with me that I have been enjoying, though not for medicinal purposes.
The scenery this week has been incredible as we weave our way through the bays and fjords of the Kenai Peninsula. McCarty fjord, carved 23 miles into the coast, was very impressive. The fjord is flanked by massive green mountains and towering cliffs. This majestic landscape was carved by ancient glaciers. I have spotted a few bald eagles, and, with binoculars, one of the deck crew members saw a brown bear mama and two cubs. As much as I love the open ocean, it’s exciting to be close to shore, so we can enjoy Alaska’s dramatic vistas and wildlife.
I am loving life at sea!
Very interesting and informative!