Rebecca Kimport, JUNE 30, 2010 part2

Posted on June 30, 2010 by Teacher at Sea

NOAA Teacher at Sea Rebecca Kimport
NOAA Ship Oscar Dyson
June 30, 2010 – July 19, 2010

Mission: Summer Pollock survey
Geograpical Area:Bering Sea, Alaska
Date: June 30, 2010

What’s in your water?

Now that we are at sea, I work a shift each day (as do all members of the crew and science team). I began my shift this morning at 0400 and reported to the Acoustics Lab to meet with chief scientist, Neal Williamson. In addition to Neal, my shift includes Abigail McCarthy, NOAA research fisheries biologist, Katie Wurtzell, awesome biologist and my fellow TAS, Michele Brustolon.We began the shift by observing our first CTD (Conductivity Temperature Depth) profiler which will be deployed at least 10 times throughout our trip. The CTD measures conductivity, temperature, and depth (used to calculate salinity) and gathers samples to measure dissolved oxygen. In other words, it measures many of the physical properties of the seawater mixture in a specific column of water. In addition, fluorescence is measured to monitor chlorophyll up to a 100 m from the surface.How it works: The CTD is lowered down to the ocean floor, collecting data on the way down. Then, on the way back up, the survey tech stops the CTD at specific depths to collect water for the samples. Upon its return, the water is collected and treated for future analysis.

Here is our CTD sensor before its launch

After our first CTD, we completed our first Methot trawl. A Methot trawl is named after the scientist who designed the net used. Here is a picture of the methot getting hauled back on deck (please note, it does actually get dark here. I woke up in the dead of night and had to wait two hours for sunrise. Sunrise is at the “normal” time of 6:30 am and I think that’s because we are on the western edge of the time zone)

Here Comes the Methot

A Methot net grabs the creatures and collects them into a codend (to make it easier for us to process) at 30-40 m below the surface – our Methot collected jellies and euphausiids (also known as krill). My first duty was to sort through the “catch” to pick out jellies. Next, we measured the weight of the krill before counting a small sample. We also preserved a couple samples for use in larger studies.

Launching the XBT

Following our Methot, I assisted with the completion of an XBT (eXpenable Bathymetric Thermograph). At left, you will see that I actually “launched” the XBT overboard. The XBT is used to collect quick temperature data from the surface to the sea floor. The data are graphed at depth vs. temperature to highlight the thermocline, that is where colder water meets water warmed by the sun. Here in the Bering Sea, the thermocline is not always noticeable as the water column is subject to mixing from heavy winds and shallow depths.

Lucky for us, it was a calm day on the water and we were able to see a distinct thermocline:

The thermocline

I think the CTDs and XBTs are really cool because they are pretty routine. Both processes are conducted all over the globe at consistent locations year after year. As you can see from the chart below, the CTDs and XBTs are marked out for the area the Oscar Dyson covers throughout the summer. (As I mentioned in my blog description, theOscar Dyson must travel the same route year after year for the pollock survey to ensure consistency in data collection).

XBT CTD locations

Beyond the Oscar Dyson, these data are collected on every NOAA cruise that I read about and that data can be used to measure how a body of water is doing in general as well as how the water column of a specific location has changed over time. For example, longitudinal data are needed to note climate change within the Bering Sea. Pretty cool huh?

Vocabulary Note: I tried to define all the new terms I used in my entry. Did you notice a term I didn’t define? Ask me about it in the comments and I will make sure to provide you with a definition.

Thought Question: In the XBT data graph, why is the X axis labeled on the top rather than the bottom? (think about your coordinate plane)

Rebecca Kimport, JUNE 30, 2010

Posted on June 30, 2010 by Teacher at Sea

NOAA Teacher at Sea Rebecca Kimport
NOAA Ship Oscar Dyson
June 30, 2010 – July 19, 2010

Mission: Summer Pollock survey
Geograpical Area:Bering Sea, Alaska
Date: June 30, 2010

Weather Data from the Bridge
Time: 1600 hrs
Latitude: 57.16 N
Longitude: 169.09 W
Cloud Cover: Dense fog
Wind: 11.56 knots
Air Temperature: 5.3°C (41.5°F)
Water Temperature: 5.09°C (41.16°F)
Barometric Pressure: 1005.02 mb

Did I mention I completed all the tasks in the previous post before lunch? That left us time to fish for pollock in the afternoon.

Fish face

Why pollock? Walleye pollock (Theragra chalcogramma) is an important fish for Alaska (and the entire United States). Although you may not know it, you’ve probably eaten pollock when you have enjoyed fish sticks or a fish sandwich at a fast food restaurant. Also, sushi lovers, artificial crab is made from pollock surimi. Walleye pollock produce one of the largest catch of any single species within US waters and accounts for over half the groundfish catch in Alaska (see:http://www.afsc.noaa.gov/species /pollock.php for more information)

How the Oscar Dyson helps? By surveying the pollock populations within the Bering Sea, scientists can gather data on these important fish – including size, gender distribution, maturity, location, and diet.

How do we find the fish? Scientists work around the clock gathering data through acoustics to identify the locations of aggregations (or schools). The Oscar Dyson has five transducers located across the bottom of the ship on its centerboard. These transducers send out signals and the data are graphed on large computer screens in our acoustics lab (more information on the acoustics lab will come in a later post) While on shift, we eagerly await word that a fish aggregation has been identified and await the trawl.

Large Jellyfish

And the trawl… As mentioned above, we were lucky enough to spot fish during my first shift and we conducted the trawl in the afternoon. A trawl is a method where a large net is cast off the back and towed behind the boat until it fills with fish. The take varies based on the aggregations (or schools) identified and the net may be out for two minutes or an hour. This first trawl was out for 45 minutes before the crew hauled it in. It was amazing how many seabirds were swarming around the net as it was pulled up and how many jellyfish were caught in the lines. The first task, once the catch is brought on deck and placed in the fish table, is to sort the specimens. We had pollock, Pacific cod, and 2 types of jellies (including theChrysaora melanaster shown at right)

Once the catch was sorted, the fish were weighed and then sexed. After they were sorted into Blokes and Sheilas (males and females), the fish also had to be measured. A small sample was dissected to remove stomachs and otoliths (ear bones of pollock that are used by scientists to determine the age of the fish) for further study.

Animals Seen on First Shift
Euphausiids (krill)
Jellies
Pollock!!!
Pacific Cod

Michele Brustolon, June 30th, 2010 part 2

Posted on June 30, 2010 by Teacher at Sea

NOAA Teacher at Sea
Michele Brustolon
Onboard NOAA Oscar Dyson
June 28 – July, 2010

NOAA Ship Oscar Dyson
Mission: Pollock Survey
Geographical area of cruise: Eastern Bering Sea (Dutch Harbor)
Date: June 30th, 2010

Weather Data from the Bridge

Time: 1600 hrs
Latitude: 57.16 N
Longitude: 169.09 W
Cloud Cover: Dense fog
Wind: 11.56 knots
Air Temperature: 5.30 C/ 420 F
Water Temperature: 5.090 C/ 410 F
Barometric Pressure: 1005.02 mb

Science and Technology Log

Fishy Fish
Why Pollock?
Walleye Pollock (Theragra chalcogramma) is an important fish for Alaska (and the entire United States). Although you may not know it, you’ve probably eaten Pollock when you have enjoyed fish sticks, a fish sandwich at a fast food restaurant, or imitation crab meat. Walleye Pollock produce one of the largest catch of any single species within US waters and accounts for over half the groundfish catch in Alaska (see:http://www.afsc.noaa.gov/species/pollock.php for more information)

Acoustic Lab with Abigail McCarthy and Neal Williamson

How the Oscar Dyson helps? By surveying the Pollock populations within the Bering Sea, scientists can gather data on these important fish – including size, gender distribution, maturity rates, location, and diet.

How do we find the fish? Scientists work around the clock gathering data through acoustics to identify the locations of populations. The Oscar Dyson has five transducers located across the bottom of the ship on its centerboard. These transducers send out signals and the data are graphed on large computer screens in our Acoustics lab. While on shift, we eagerly await word that a fish population has been identified and await the trawl.

First trawl net to come up on Leg 2

Here I am getting ready to sort the first catch in my foul weather gear!

And the Trawl…
Luckily for me, fish were seen on my first shift and we conducted the trawl in the afternoon. The take varies based on the populations identified and the net may be out for two minutes or an hour. This first trawl was out for 45 minutes before the crew hauled it in. It was amazing how many seabirds were swarming around the net as it was pulled up and how many jellyfish were caught in the lines. The first task once the catch is brought on deck and placed in the fish table, is to sort the specimens. We had Pollock, Pacific cod, and 2 types of jellies. Once the catch was sorted, the fish were weighed and then sexed. After they were sorted into Blokes and Sheilas (males and females), the fish also had to be measured. A small sample was dissected to remove stomachs and otiliths (ear bones of Pollock that are used for aging the fish) for further study.

Abigail McCarthy and Kathy Hough taking samples of Pollock stomachs and otiliths

The wet lab

Personal Log

While this is a continuation of the first log (it was way too long!), it focuses on the why we are studying Pollock and how the first trawl went. No fishing was done until after lunch. When the net did come up, there were five of us in the wet lab where we processed the catch; Abigail McCarthy, Kathy Hough, Rebecca Kimport, Katie Wurtzell, and me. It was very interesting to see all the information that came from a sampling of Pollock: weight, length, sex, stomach contents, and otiliths (ear bones). This brought us to the end of our 12 hour shift at 1600 hours.

Exercise was next…running on the treadmill was by far the weirdest feeling as the boat is rolling you feel as though the incline is moving up and down on its own and you have to hold on at different times. This is with pretty calm seas too! Dinner was fabulous as always. We have been spoiled here on the boat with meals like king crab legs, salmon, prime rib, Jamaican jerk chicken. Now do you see why I have to try to exercise EVERYDAY!!! I think the hardest part right now is trying to get to bed early enough so when 0315 arrives, I can get up and going.

Workout room

Animals Seen on First Shift
Euphausiids
Jellies
Pollock!!!
Pacific Cod

New Vocabulary
Blokes: male Pollock
Sheilas: female Pollock
Otiliths: ear bones of Pollock that help age the fish (they have rings that are counted much like trees)