NOAA Teacher at Sea
Aboard NOAA ship Oscar Dyson
July 1-22, 2018
Mission: Walleye Pollock Acoustic Trawl Survey
Geographic Area of Cruise: Eastern Bering Sea
Date: July 6, 2018
Weather Data from the Bridge
Longitude: 170.39 7756W
Sea Wave Height: 3-4 feet
Wind Speed: 18.87 Knots
Wind Direction: 126º true
Air Temperature: 8.7ºC
Barometric Pressure: 1002.0 milibars
Science and Technology Log
Note: This Walleye Pollock Acoustic Trawl Survey is a way to estimate the amount of fish that are present in a targeted area of the Bering Sea. NOAA Scientists have been conducting these surveys since the 1970’s. It is important work necessary to manage the pollock population. (Pollock is a billion dollar food industry, thus a very important ocean resource.) These population estimates are part of the information used to determine how much fish can be caught in the Bering Sea (fishing quotas, MSY-Maximum Sustainable Yield) that still allows the population to reproduce and survive in adequate numbers.
What does it take to prepare for an Acoustic Trawl Survey?
The fisheries scientists plan their sampling area based upon past surveys so that each part of the Bering Sea is covered over a period of time, in this case June through August;decisions must be made about who will be going on which leg of each trip. They also determine what research projects will be conducted, what specimens should be collected, and what information they need to obtain from this work. Other scientists also make requests, such as specimen collections or oceanography equipment deployments in target areas to obtain information for their own research projects. A document called Project Instructions is developed to include these cruise objectives and a list of all the supplies and equipment needed to conduct the research projects. Once the Project Instructions document is complete, it must be sent for review to NOAA administration, then to MOC-P (Marine Operations Center-Pacific)- which is a home location for NOAA to monitor its’ fleet of NOAA vessels. Now on to the NOAA Corps officers who are also preparing the ship for this cruise. In cases of requesting to sample the western Bering Sea (near, but outside of Russian waters), the State Department must approve it. Once this plan has been approved, many preparation activities begin.
A detailed spreadsheet is developed that lists all supplies needed for the fishing and research work. This includes vials for sampling, chemicals for preserving, tools needed to conduct research, and fishing gear. Some supplies are loaded on the ship when in port in Dutch Harbor or Kodiak, but other supplies are shipped in shipping containers or flatbed trailers. A large ship carries these on the ocean from Seattle to Dutch Harbor, and then tractor trailers bring the nets to the ship.
Then scientists work with the ship’s crew to make final decisions regarding haul locations. While the general area to fish is determined prior to setting sail, specific haul locations (along survey tracklines or transects) are determined as the scientists monitor the location and distribution of fish using sonar readings during sailing.
I am enjoying life at sea and settling into the maritime routines that ensure the ship runs smoothly. NOAA ship Oscar Dyson is a small city with each person having very specific responsibilities for safety and operations. There are approximately 30 people on board. My work shift is from 4pm – 4 am each day. (There are no days off.) The ship has 5 labs (Wet lab, Dry lab, Acoustics Lab, Chemical Lab, Fish Lab) I spend my work shift after each haul, in the fish lab. There we identify the species that are caught, collect specimens for research and record weights and measurements of targeted species. This allows calculation of the amount of each species caught, which are used to calculate population estimates. (This is called processing the catch.) I also spend time writing blog posts, planning lessons about the work here, and interviewing staff on board to learn about their career paths. I will also use this information to teach students about the science related to this work and the career opportunities in this field. Well, a net is being pulled up now, so off to the fish lab I go.
Did You Know?
Sonar readings can be used to “see” what is in the water column. This is due to sound waves that bounce off what is in the water (“echoes”). Strong echoes come from pollock because sound waves bounce off the gas in their swim bladders. These echoes can be shown on a computer screen as the ship sails along, making a plot called an “echogram”.