Emily Cilli-Turner: Back on Land, August 13, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 13, 2018

 

Weather Data for Claremont, CA from National Weather Service:

Latitude:  34.1368º N

Longitude:  117.7076º W

Wind Speed: 12 mph

Wind Direction: SSW

Air Temperature:  29.4º Celsius

Humidity: 36%

Personal Log 

Well, NOAA Ship Oscar Dyson docked in Dutch Harbor on August 11th from the 19-day journey in the Eastern Bering Sea.  During our time at sea, I learned so much and got to know both the NOAA scientists and the crew and officers on the ship.  When I applied for the Teacher at Sea program, I knew that it would be an invaluable experience, but it far exceeded my expectations.  I learned about the work of the NOAA scientists pretty much non-stop and any question I had was answered in detail, which allowed me to have a robust picture of the work the NOAA scientists do, the different types of scientific instruments they use and the underlying principles behind them as well as the day-to-day operations of a scientific vessel such as NOAA Ship Oscar Dyson.  Additionally, I also ate the best food of my life made by the stewards; there was always amazing entrees and dessert at every meal!

NOAA Ship Oscar Dyson

NOAA Ship Oscar Dyson in Dutch Harbor, Alaska

After we came into port, I was able to explore the town of Dutch Harbor as well.  Along with other NOAA Scientists and the ship’s medic, I explored the Museum of the Aleutians in town and learned about the native people of the island and their traditions as well as the military encampments that were built on Unalaska (the island where Dutch Harbor is) during WWII.  The next day we went up Ballyhoo mountain and saw the ruins of one of the WWII bases.  The view from there was amazing and we saw all around Unalaska.  I was surprised in Dutch Harbor to see so many bald eagles everywhere!  The next day I said goodbye to the many people I got to know aboard the Oscar Dyson, many of whom were staying aboard for the next leg or for a long time thereafter.  I was surprised how easily I transitioned to life aboard the boat and it still feels a bit weird to not be moving all the time!

 

Emily Cilli-Turner: Journey’s Coming to an End, August 9, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 9, 2018

 

Weather Data from the Bridge:

Latitude: 60º28.02 N

Longitude: 175º25.19 W

Wind Speed: 8.77 knots

Wind Direction:  236.54º (SW)

Air Temperature:  8.8º Celsius

Barometric Pressure: 1010.7 mb

Sea Wave Height: 2-3 feet

Visibility: less than 1 nautical mile

 

Science Log

I had a chance to interview the chief scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto, and ask her about her career path to working at NOAA as well as recommendations she has for anyone interested in an ocean career.

Taina knew that she wanted to pursue a career in science ever since she was a child as she has always been interested in the outdoors and collecting and observing things.  During college, she took an oceanography course as a junior and knew she wanted to work with the ocean.  Her college advisor recommended that if she wanted to pursue science she needed to do a field program.  As a junior, she was able to secure participation at a marine lab in the U.S. Virgin Islands, which inspired her choice to go to graduate school and study invertebrate zoology.

At NOAA, Taina really enjoys her colleagues and the field work, which includes the pollock counting work she is currently doing on NOAA Ship Oscar Dyson.  She feels that her work at NOAA is an opportunity to contribute to the preservation of our planet.  Additionally, she enjoys doing outreach at NOAA and talking to people about her work and answering questions about the ocean.  Often, discussions with the public involve balancing what they have heard about fisheries and overfishing in the news versus the reality and experiences Taina has had in the field counting pollock in the Bering Sea and Gulf of Alaska.

The advice that Taina has for those wanting to work for NOAA is to get an internship.  Students can find internship opportunities through the NOAA website and there are avenues into NOAA experience for students at the middle and high school level as well as college students.  These internships are a great way to get hands-on experience (as I can attest!) and some of them are even paid if students apply for the Hollings scholarship. Taina also recommends reading some of the following books to get an idea about what it is like on a field placement: “The Log from the Sea of Cortez” by John Steinbeck, “Moby Duck” by Donovan Hohn, and “Cod” by Mark Kurlansky.

Taina Honkalehto

Chief Scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto

 

Personal Log

The wet lab aboard NOAA Ship Oscar Dyson is where most of the action happens during my shift.  When a haul comes in, we are responsible for processing the catch and obtaining the needed measurements so that the MACE team can put together their report on the health of the pollock population.  The catch is released from the trawling net onto a hydraulic table that can be dumped onto a conveyor belt.  The first job to be done is to sort the catch, where all species that are not adult pollock are separated out.

Pollock on belt

Adult pollock from a haul on the sorting belt

The next task is to measure the length of a subsample of about 300 of the adult pollock in the catch.  This helps the NOAA scientists to create histograms of pollock lengths to compare between hauls.  Finally, about 30 pollock are separated to measure length, weight and to determine gender and maturity and another 30 have length and weight measured, otoliths taken, and ovaries weighed and collected if the pollock is a spawning female.  During my shift, there are six of us in the fish lab and we are working like a well-oiled machine!

Today we are starting the long transit back to Dutch Harbor.  It is bittersweet since I feel like we have a nice routine down in the fish lab and I finally feel used to the motions of the ship.  However, I am grateful for this opportunity and for all the great people that I have gotten to know during my time on NOAA Ship Oscar Dyson.  Also, we finally saw some blue sky again and a rainbow even came out for a moment!

rainbow

A small rainbow over the Bering Sea

 

Did You Know?

The NOAA Ship Oscar Dyson was launched on October 17, 2003. It is named after Alaskan fisherman Oscar Dyson and there is a smaller boat on board named after his wife, Peggy Dyson.

Emily Cilli-Turner: Plenty of Fish in the (Bering) Sea, August 6, 2018

 

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 6, 2018

 

Weather Data from the Bridge:

Latitude: 58 04.81 N

Longitude: 174 06.88 W

Wind Speed: 6.88 knots

Wind Direction: 275.19 (NW)

Air Temperature: 10.0 C

Barometric Pressure: 1013.2 mb

Visibility: 6 nautical miles

Sea Wave Height: 4 feet

Sky: Overcast

 

Science Log

While the techniques written about in the previous blog post ensure that when we use the trawling nets we mostly catch pollock, there is usually a small amount of by-catch in each haul.  By-catch means ocean life other than pollock (the desired catch) that we bring up in a haul using the trawling net.  This post will focus on some of the creatures that I have seen in the catches during my time on NOAA Ship Oscar Dyson.

 

Principal species of interest:

Pollock: The scientific name for these pollock (known as Alaska pollock or walleye pollock) is Gadus chalcogrammus.  We often catch many different ages of pollock, from age 0 pollock up to large adult pollock and these range in length from a few centimeters up to about 62 centimeters. Pollock is most of what we catch, and they are easy to identify by their three dorsal fins and speckling.  Pollock mainly eat euphausiids and copepods, but also sometimes eat the age 0 pollock.

Adult pollock

Adult pollock

 

By-catch species:

Chum Salmon: Chum salmon (Oncorhynchus keta) is one of the five types of salmon and lives for about 6 years on average.  Like all salmon, they are spawned in freshwater and then migrate out to the ocean.  Once they return to the freshwater and spawn, they die about two weeks later. They mostly eat zooplankton and insects, but have been known to eat comb jellyfish as well.

chum salmon

Student intern Liz Allyn with a chum salmon from a haul.

 

Jellyfish: We see several types of jellyfish in each catch, but we mainly see the Northern Sea Nettle (Chrysaora melanaster).  We have also seen Northern Sea Nettle swimming near the surface before sunrise when we are pole fishing for pollock.  The word melanaster translates to “black star,” which you can identify in the pattern on the bell of this jellyfish. The bell diameter can reach up to 12 inches and the tentacles can grow as long as 10 feet. As climate change has warmed the surface temperatures of the Bering Sea, the population of Northern Sea Nettle is increasing.  Northern Sea Nettles mostly eat zooplankton, but sometimes also eat pollock!

Chrysaora melanster

Chrysaora melanster

Smooth Lumpsucker: Smooth lumpsuckers (Cyclopterus lumpus) are named so because of an adhesive disc on their underside that helps them suction onto the ocean floor.  These fish spend most of their time on the bottom of the ocean and are not particularly good swimmers. The roe (eggs) of the lumpsucker is a delicacy in Scandinavia.

Flatfish: Alaska Plaice & Yellowfin Sole: We have also caught two types of flatfish during my time aboard the ship: yellowfin sole (Pleuronectes aspera) and Alaska Plaice (Pleuronectes quadrituberculatus). These peculiar looking fish can be identified by having both eyes on top of their head.  When they are spawned, these fish have eyes on either side of their head, but as they get older the eyes migrate to be on the same side. These fish mainly reside on the ocean floor, where they eat polychaetes and amphipods, such as worms and mollusks.

Capelin: The capelin (Mallotus villosus) is a small fish in the smelt family reaching a length of about 10 inches.  It feeds mainly on plankton and krill.  The most interesting thing about capelin is their smell; if you put their scales close to your nose you will smell cucumbers!

Capelin

Capelin

 

Personal Log

While the weather since boarding the NOAA Ship Oscar Dyson has largely consisted of some high winds and big swells, there have been one or two nice days in the Bering Sea. On these days, we have taken the opportunity to go outside.  On one particularly nice day where the sun was shining, there was a mini corn-hole tournament on the deck.  After thinking that my time on the ship was the least amount of time spent outside during the summer, this was a nice way to spend the after-dinner time.

corn hole

Operations officer LT Carl Noblitt and student intern Grace Workman playing corn-hole on the deck.

I am also grateful for NOAA scientists Mike Levine and Darin Jones, who have made me feel like an expert in the fish lab.  At this point, I know more about pollock than I ever thought I would.  In the fish lab, I primarily am responsible for measuring the length of the pollock sample.  However, Mike and Darin have also taught me about pollock anatomy and how to tell if a pollock is male or female.  I have also become good at extracting the otoliths, which involves a precise cut of the pollock.  For a person with almost no experience working with biological specimens, much less fish, I finally feel like a useful part of the team.

Did You Know?

The Bering Sea is an extremely important fishing location and the United States catches over $1 billion of seafood here each year.

Emily Cilli-Turner: One Fish, Two Fish….Pollock Counting Techniques July 29, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 29, 2018

 

Weather Data from the Bridge:

Latitude: 57° 10.46 N

Longitude: 171° 58.29 W

Wind Speed: 11.16 knots

Wind Direction: 77.54° (NW)

Air Temperature: 10.1° C (Manual Reading from the Bridge)

Barometric Pressure: 992.7 mb

Visibility: 6 nautical miles

Sea Wave Height: 3 feet

Sky: Overcast

 

Science Log:

How do the scientists aboard NOAA Ship Oscar Dyson estimate the number and biomass of pollock in the Eastern Bering Sea? By using the science of statistics, of course! When political strategists want to determine what percentage of voters support a specific candidate or issue, they take a sample from the population of all registered voters. Voters in this sample are then asked about their preferences and statistical techniques are employed to extrapolate the results from the sample to the entire population and measure the margin of error.  Similar statistical techniques are employed by the scientists on NOAA Ship Oscar Dyson, but as you can imagine it is more difficult to sample pollock than voters that can be called on the phone!

Before each pollock survey begins, a set of transects is created for the Eastern Bering Sea.  These transects are paths for the ship to follow along which the scientists sample the pollock.  As you can see below, the transects for this survey are a fixed distance apart and cover the entire area of interest.  Generally, the transects are straight lines created to be perpendicular to the ocean depth grade. This allows for the scientists to encounter a variety of species as well as different ages of pollock to gain a robust picture of the ocean life in the area.

transect

The transects for this survey leg can be seen as the straight lines. The other markings are places where the trawls have been done and other scientific instruments have been deployed.

The NOAA Ship Oscar Dyson follows the transects during daylight hours, continuously recording water column acoustic backscatter data using EK60 instruments mounted on the bottom of the centerboard.  Scientists monitor the backscatter images, and when they observe sufficient pollock or other fish aggregations they  use the trawling nets to take a random sample of the fish and other ocean life they observed.  The trawling net is 140 m long with a vertical mouth opening of 25 m and horizontal mouth opening of 35 m. The net is deployed from the back of the ship and dragged at a fixed depth for an amount of time determine by the lead scientist to ensure a large enough sample. Once the trawling net is hauled in, the sample of marine fish and invertebrates is processed in the wet lab and entered into a database. Later the pollock numbers and weights by length are combined with  recorded acoustic data to create a robust estimate of the pollock population in the Eastern Bering Sea.

After the catch comes in, the first job in processing the sample is to sort the specimens from the trawling net.  The first part of the net to come in is called the pocket net. This small net, also called a recapture net,  has a fine mesh and is designed to capture small species such as krill, age 0 pollock and jellyfish which slip through the meshes of the large trawl.  After the pocket net is processed, we process the codend, the closed end of the net and the main section where larger fish enter and are captured.  The fish in the codend are sorted by species.  The scientists can choose to measure the length of all the pollock in the haul or, if it is a particularly large catch, split the haul and measure length of a subsample of pollock.  Other species are also identified and their length is measured for later estimates of the total biomass that pollock make up as compared to other species.  Smaller species such as krill are weighed in aggregate instead of individually.

codend

The codend of the trawling net.

Sample analysis consists of measuring the lengths of approximately 200-400 adult pollock in the catch using the magnetic length board.  This is just one of the numerous software and instruments created by the MACE (Midwater Assessment and Conservation Engineering) group at NOAA in Seattle to make analysis easier and more automated.  The length distribution of the adult pollock helps scientists determine the approximate age distribution of pollock in the sample and it also helps them compare this distribution to other samples taken in the Eastern Bering Sea.  A subsample of about 50 pollock from the haul is taken to get more in-depth measurements. From these pollock, we measure both the length and weight and a subsample from the 50 is taken to determine the gender, measure maturity (i.e. what stage in the life cycle the pollock is at), and collect the otolith (ear bone), which gives a more accurate measurement of the pollock’s age.

Personal Log:

At this point, I am getting used to life at sea and have a nice routine.  The beginning of my shift, from 4am to a little past 7am, starts at sunrise and during which we resume our path along the transect.  No trawling operations are conducted at night, but there is still excitement.  If the underwater acoustics show that the pollock are at an appropriate depth, we can go pole fishing off the boat.  NOAA scientist Mike Levine is interested in post-capture mortality of pollock and the feasibility of tagging pollock.  Thus, he would like to catch pollock using a fishing pole, which puts much less stress on the pollock and increases the chance of their survival after the catch, instead of the trawling nets.

fishing

NOAA scientist Mike Levine with a pollock caught with a fishing pole.

As an instructor of mathematics, I have little knowledge of fish biology, but the scientists are great teachers!  I have been given a crash course on fish anatomy using specimens from the catch and I have learned how to sex the fish as well as how to collect the ovaries and the otoliths (ear bones).  If you asked me a week ago if I ever thought I would know so much about pollock after just a couple days on board, I would have laughed.  It has been great being the student and being able to learn so much in such a short time with real hands-on experience!

Did You Know?

Most of the personnel that are responsible for piloting and maintaining the ship are part of NOAA Corps, which is one of the seven uniformed services of the United States.

Lee Teevan: Sea Shanties, Anyone? July 2, 2018

NOAA Teacher at Sea

Lee Teevan

Aboard NOAA Ship Oscar Dyson

July 1 – 21, 2018

 

Mission: Acoustic Pollock-Trawl

Geographic Area of Cruise: East Bering Sea

Date: 2 July 2018

 

Weather Data from the Bridge

Latitude: 60 N

Longitude: 170W

Sea Wave Height: 2ft

Wind Speed: 18 knots

Wind Direction: 116 SE

Visibility: 7 miles

Air Temperature: 6.4°C

Barometric Pressure: 1028.1 mb

Sky: overcast

Clouds over Dutch Harbor, AK

Stunning cloud formations as viewed from the airplane.

 

Science and Technology Log

Sailing on the East Bering Sea (EBS) may conjure images of a crew roughing it with just the basics.  The captain in the image is steering with a large-spoked wooden wheel while those below sing sea shanties of longing, exploration and discovery.

Here on the Oscar Dyson, it’s a high-tech version of the cruises of days past. On our three-week cruise to track pollock migrations, we land-dwelling mammals have state-of-the-art equipment to assess the focus of our exploration.  We have on-going acoustic surveys which show the movement of organisms around the boat. When we reach our first station later today, we will carry out a trawl and be able to see from 2 cameras on the trawl exactly which organisms are present around the station.  From the trawl, we will evaluate the length and ages of pollock.  There will be more to come on this aspect of the expedition after we reach our first station.

Science was also behind the protocol of our ship’s departure from Dutch Harbor, AK. Before leaving, the Oscar Dyson required at least 4 hours to fill its tank with 55, 000 gallons of diesel fuel. There are no pitstops along the way!

Blair Cahoon is overseeing deck preparation.

Blair Cahoon oversees deck preparation during the safe fueling of the Oscar Dyson. The yellow boom is on the water in the background.

Blair Cahoon, the ship’s wiper, was onboard during the fueling of the ship.  He explained the reasons for the boom, the 1-foot yellow floating barricade which prevents potential oil spills. Aboard the ship, white absorbent plastic was placed over fuels in case the tanks overfilled, and the gas splashed up. In addition, the marine chemist carried out fuel pump testing at certain increments.

After completely fueling the ship, the Oscar Dyson was untethered and set off through the Iliuliuk Bay, passing by pods of humpback whales and uninhabited islands.

Leaving Dutch Harbor, AK

Departing Dutch Harbor, AK through the calm Iliuliuk Bay.

As we left Dutch Harbor, I took in the receding landscape and welcomed the view of the water world which will be our home for the next three weeks. I thought of my fellow land-dwellers, past and present, who have sailed the EBS and imagined joining in their hearty renditions of sea shanties celebrating the exploration and discovery to come.

Personal Log

Before we reach our first station, I am acquainting myself with the labs and the procedures to be carried out.  We also had down time during the ship’s transit to the initial station and I took many photos with several types of cameras. Two of my favorite cameras are the Holga medium format and my dependable Canon AE-1.  The black and white photos I print from film are my attempt to capture stark beauty of the water around me.

Did You Know?

Filling up the gas tank of the Oscar Dyson costs more than $150, 000.00!

Animals Seen Today

Humpback whales

Puffins

Fulmars

 

 

Thomas Ward, September 16, 2010

NOAA Teacher At Sea: Thomas Ward
Aboard NOAA Ship Miller Freeman

Mission: Fisheries Surveys
Geographical Area of Cruise: Eastern Bering Sea
Date: September 16, 2010

Question and Answer for the Teacher at Sea (NOAA)

Let’s jump right in, and not into the Bering Sea, it is too cold.

We have not seen any NOAA buoys, or at least I have not.  NOAA does maintain numerous buoys but our mission aboard the Miller Freeman is strictly biological, juvenile flat fish to be specific.  The types of little fish that we have caught and persevered for further study (remember the freezer) are; Yellowfin Sole, Pacific Halibut, Northern Rock Sole, Flathead Sole, Alaska Plaice, Arrowtooth Flounder, Kamchatka Flounder Greenland Turbot, and larvae of Long Head Dab.  These fish that are being saved are relatively small, about 1-3 inches long, they are juveniles. The scientists are trying to determine the mechanism that controls the development of these juveniles into adults. I was also happy to learn that the scientists that are doing the sampling are also the same scientists that are going to be doing the work back in the lab. The identification of these youngsters seems to be effortless by the group of scientists I am working with, they really know their stuff.  I have not seen too many ships here while we are out to sea.  Last night I did see a light in the distance and assumed it was another ship but did not confirm it with the bridge. We do not fish to catch food for us on board.  In fact there are so many regulations regarding fishing that we just focus on the mission and let the cooks in the galley do what they do, and let me tell you it is good.  We often do get a glimpse of land, the pictures of the volcanoes on previous blogs are taken from our ship.

This video shows me measuring flat fish on the magnetic measuring board that I mentioned in an earlier blog.  After imputing the species and other pertinent data, on a touch screen monitor, the fish is laid on the board and a device is touched to the board where the tail is.  The length of the fish is recorded electronically.  The fish that you see in the video are adults of the juveniles related to this FOCI Research Project and we still gather quantitative data on them.  After we catalog them they are returned to the ocean where they have a very good chance of surviving.  Keep those questions coming.

Sunset

Sunset

Richard Chewning, June 13, 2010

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 13, 2010

Weather Data from the Bridge

Position: Eastern Bering Sea
Time: 1530
Latitude: N 56 15.380
Longitude: W 164 14.010
Cloud Cover: Overcast with light spray
Wind: 30 knots
Temperature: 5.4 C
Barometric Pressure: 1002.7 mbar

Science and Technology Log

Around 0940 Thursday morning we began our first summer 2010 pollock survey transect. Researchers have been conducting acoustic pollock trawl surveys since 1979 and bottom trawl surveys since the1950’s. The 31 transects in this year’s survey run roughly north south and progress from the eastern Bering Sea across to Russian waters in the western Bering Sea. The transect lines range in length from 60 to 270 nautical miles and are spaced 20 nautical miles apart. A nautical mile is slightly longer than a standard mile and is useful for navigating charts (maps used at sea). Only surveying during daylight hours, the Dyson will continue to run these transects till the beginning of August. A transect is a path (usually a straight line) during which the number of occurrences of an observable fact are counted (such as the abundance of pollock).

The beginning transect was marked by the launching of an expendable bathythermograph (XBT) probe. While the name might seem long and somewhat complicated sounding at first, the instrument and data being recorded are actually quite straightforward. Expendable refers to the fact that the probe is not recovered after being deployed. How is the data sent back to the Dyson you ask? Two long thin copper wires uncoil from the launcher and probe allowing data transfer back to the Dyson. The wires are broken by hand once the probe has reached the bottom. The rest of the story is revealed by subdividing the word ‘bathythermograph’ and defining its parts. ‘Bathy’ is a prefix that means deep or at depth. ‘Thermo’ is another prefix that refers to heat or temperature. Finally the word ‘graph’ means to draw a relationship between multiple variables (such as depth of the water and temperature). So an expendable bathythermograph is a disposable probe that profiles the temperature from the surface to the sea floor.

XBT probe and launcher

The XBT is a very helpful tool that enables the scientists onboard the Dyson to gather temperature data while on the move. Being able to capture this data without slowing down and stopping is a big time saver. Bringing a ship to a stop on the water takes much more time than stopping a car on the highway, and deploying a reusable instrument to the bottom and back takes even more time, manpower, and resources. Temperature data allows fish biologists to better understand how water temperature and the abundance of pollock and their food supply are related.

Darin deploying XBT

Later that afternoon, we also performed our first Tucker trawl. The Tucker trawl is a cleverly designed system of three nets that allows for three discrete (separate) samples during a single deployment. The Tucker trawl is designed to catch the zooplankton (animal-like plankton) that pollock eat such as euphausiids. This net allows researchers to study the differences of zooplankton distribution at various layers in the water.

Deploying the Tucker trawl

Tucker trawl messenger

To catch these small organisms, the net needs to a have very small openings. In fact, the openings in the net are only half a millimeter in width or roughly 1/3 the thickness of a dime! The three nets are attached to a metal frame mounted on metal skis that resembles a backwards dog sled. These skis allow the sled to slide along the seafloor and avoid snagging any obstructions. The Tucker trawl is initially deployed with one net open. The first net is closed and the next net is opened using a heavy brass messenger sent down the wire connecting the Tucker trawl to the Dyson. The messenger is attached to the wire cable at the surface and allowed to slide down the cable to the net being towed in the water. The impact of the messenger triggers a spring in a latch that closes one net and opens another net. The second net is closed and the third net is opened in the same fashion. Samples are taken at the surface, at the bottom, and evenly from the seafloor all the way to the surface. Attached to the sled are sensors to record temperature and depth, the flow of water passing through the net, and the time the net spends on the bottom. The catch is collected at the end of the net in a removable cod end jar. Any jellyfish are removed from the catch, identified, and measured. The remaining zooplankton is weighed, and a small subsample is saved and preserved for later identification.

Richard sending messenger down to the Tucker trawl

Euphausiid

Hyperiid amphipod

Personal Log

At sea, a person can easily lose track of time and even forget the day of the week as work aboard the Oscar Dyson continues uninterrupted seven days a week. I was reminded that today was Saturday by a special meal served by the galley. Rick and Floyd prepared a delicious dinner of real Alaskan king crab, prime rib, baked potatoes, vegetables, and fresh baked bread. This was a real treat (along with the cookies and cream ice cream, always a fan favorite) for the crew. There was plenty to go around, and all were well satisfied.

This was actually not my first encounter with king crab on this cruise. The day before, we had the unprecedented surprise of catching a red king crab with the Tucker trawl during the bottom net deployment. To the best of the knowledge of all the scientists onboard, this had never happened before. You might remember that the Tucker trawl is designed to catch zooplankton, which are typically small in size. This unlucky crab was so large she didn’t even fit in the cod end collection jar at the end of the net. In the end the crab was lucky as we opted to release her after recording her weight and species as we already had enough crab in the freezer for dinner the following night!

Richard holding red king crab

Dinner! Lucky for her, the crab Richard’s holding was released back to the sea!

Leisure Activities

Time spent not working onboard the Dyson can be considered among a person’s most precious possessions. Working long hours, the NOAA Corps officers, visiting scientists, and crew aboard the Dyson usually only have a few hours of time before starting their next scheduled watch or shift. Sleeping is often the first order of business on a person’s to do list. Whether you take only a short nap or can sleep for several blissful hours, time in one’s rack (bed) is essential for a productive, happy, and safe crew. Often one’s sleep schedule will necessitate missing a meal but the rest gained seems well worth the trade off. A very nice service offered by the galley is making and setting aside a plate for those crew members missing a meal if requested.

Other down time activities include reading, listening to music, and working out. The Dyson also has an impressive movie collection (including many recent titles not yet released on DVD) that is administered by the Department of the Navy. New titles are added monthly. The Dyson has a very comfortable lounge for watching movies that also includes a wide selection of magazines and books. Keeping connected with the outside world is also very important while at sea. With relative reliability, people can access the internet to answer emails, pay bills online, and surf the web for news and can call friends and family back home using the satellite phone.