NOAA Teacher at Sea
Richard Chewning
Onboard NOAA Ship Oscar Dyson
June 4 – 24, 2010
NOAA Ship Oscar Dyson
Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska (Kodiak) to eastern Bering Sea (Dutch Harbor)
Date: June 10, 2010
Weather Data from the Bridge
Position: Bering Sea
Time: 2147 hours
Latitude: N 56 48.280
Longitude: W 161 48.549
Cloud Cover: Overcast with fog
Wind: 9.2 knots from NE
Temperature: 4.6 C
Barometric Pressure: 1010.8 mbar
Science and Technology Log
In addition to hosting fish biologists studying walleye pollock, the NOAA ship Oscar Dyson also has groups of researchers studying birds and marine mammals aboard. Both the birders and marine mammal observers are conducting supplementary projects taking advantage of the Dyson’s cruise track. As the Dyson sails back and forth across the Bearing Sea along equally spaced parallel transects, these researchers are able to survey a wide area of habitat, investigating not only what animals are present and absent in these waters, but also how many are present (called abundance). These surveys are considered passive since these researchers are not actively directing the ship’s movements but are surveying along the cruise track laid out by the fish biologists.
Our migratory bird observers are Liz Labunsky and Paula Olson from the United States Fish and Wildlife Service (USFWS). They are members of the North Pacific Pelagic Seabird Observer Program and are providing data for the Bering Sea Integrated Ecosystem Research Project. Pelagic seabirds are birds found away from the shore on the open ocean. Liz is from Anchorage, Alaska and has been involved with this project since 2006. Calling Gloucester, Massachusetts home, Paula is new to these waters but has spent years studying the birds of Prince William Sound as part of the ecosystem monitoring efforts resulting from Exxon Valdez oil spill.
Liz and Paula work for two-hour alternating shifts from the bridge. They continuously survey an area of water 300 meters by 300 meters in size. They are looking for birds both on the water’s surface and flying through the air. Liz and Paula must have quick eyes and be very familiar with a wide variety of birds. Identifying birds on the move can be very challenging. Often you only have only a few seconds to train your binoculars on your target before your query becomes a spot on the horizon. In addition, the same species of bird can vary greatly in appearance. Liz and Patti may only see a handful of birds over an entire morning but can also witness hundreds at any given moment!
One constant challenge for observers aboard moving vessels is counting the same bird multiple times. For example, you will often spot northern fulmars flying laps around the Dyson when underway. To avoid introducing this bias (or error) in their survey, flying birds are only counted at certain time intervals called scan intervals. The frequency of these scan intervals are determined by the speed at which the Dyson is traveling. For example, when the Dyson is traveling 12 knots, birds flying are counted every 49 seconds. If the Dyson is traveling slower, the time is reduced.
While very familiar with the coastal birds of Georgia, I have been introduced to several new species of birds found in the Bering Sea. I have become a big fan of the tufted puffin. Easily identified by their reddish orange bills, tufted puffins resemble little black footballs when flying. These birds dive in the frigid waters to catch fish, their favorite prey. The black-footed albatross is another bird new to me identified by the white markings around the base of the beak and below the eye along with its large black feet. One of my favorite observations with Liz and Patti was identifying a group of northern fulmars so tightly packed on a piece of driftwood that it showed up on the ship’s radar!
Personal Log
Just before my shift ended around 1545 hours, a call came over the radio from Yin, one of the Dyson’s three marine mammal observers. She reported that a large number of humpback whale blows had been spotted on the horizon. A blow refers to the spray of water observed when a whale surfaces for a breath of air. Like all mammals, whales have lungs and must surface to breath. The humpback whale is a baleen whale that feeds on krill (small marine invertebrates that are similar to shrimp) and small fish in the summer. Krill is a major link in the marine food web, providing food for birds, marine mammals, and fish such as pollock. Baleen whales have plates made of baleen instead of teeth that are used to separate food from the water. Baleen resembles a comb with thick stringy teeth. Think of the movie Finding Neo when Marlin and Dory are caught in the whale’s mouth.
Not sure how many whales constitute a large group, I eagerly headed to the bridge to see if I could catch a glimpse of this well-known marine mammal. I quickly climbed four companionways (a stair or ladder on a ship) up to the flying bridge from the main deck where the acoustics lab is located. Upon reaching the highest point on the vessel, I was told that I was in for a treat as we were approaching a massive aggregation (a group consisting of many distinct individuals or groups) of humpback whales. Whales often travel in small social groups called pods, but this gathering was much larger than usual. This gathering was more than a single pod of whales as there were so many blows you didn’t know which way to look!
The Dyson’s CO (Commanding Officer), Commander Michael Hoshlyk, carefully maneuvered through the whales affording the growing gathering of onlookers a great view. Observations from the Dyson’s fish biologists and birders supported the hypothesis from marine mammal observers that these whales were almost certainly gathered together to feed. Evidence to support this conclusion included acoustic data and the presence of large numbers of seabirds. The Dyson’s transducers showed large acoustic returns that were most likely from plankton (organisms that drift in the water) such as krill. There were also countless numbers of shearwaters (medium-sized long winged sea birds) gathered where the whales were swimming. Estimating the number of whales and shearwaters proved difficult because of their large numbers. The first group of whales numbered at least 50, and we later encountered a second group of humpbacks that numbered around 30. The shearwaters numbered in the thousands! I was able to capture some great pictures of the flukes (the horizontal tail of the whale used for propulsion) and blows of the humpbacks by holding my camera up to the powerful BIG EYES binoculars. Looking through the BIG EYES gave me the sensation being so close that I almost expected to feel the spray of water every time the whales surfaced for a breath. I counted myself fortunate to see this inspiring and unforgettable sight. Along with the beautiful weather, the opportunity to see these amazing creatures of the deep made for a very enjoyable cruise to the beginning of the pollock survey.
New Word of the Day – Bearing
You will often hear the word ‘bearing’ used on the bridge of the Dyson. A bearing is a term for direction that relates the position of one object to another. For example, the Dyson’s lookout might call out, “Fishing vessel, bearing three one five degrees (315°)”. This means the fishing vessel is in front of and to the left of the ship when facing toward the bow. A bearing does not relate distance, only direction. The area around the Dyson is divided into 360 equal parts called degrees. One degree is equal to 1/360th of a circle. When calling out a bearing, degrees allow for precise communication of an object’s relative position to that of the Dyson. The Dyson always has a member of the deck crew stationed on the bridge serving as lookout when underway. The lookout’s responsibility is to monitor the water around the Dyson for boat traffic, hazards in the water, or any other object important to the safe navigation of the ship.
