Melissa George: Would You Like Fries with That? August 5, 2013

NOAA Teacher at Sea
Melissa George
Aboard NOAA Ship Oscar Dyson
July 22 – August 9, 2013

Mission:  Pollock Survey
Geographical Area of Cruise:  Gulf of Alaska
Date:  August 5, 2013

Current Data From Today’s Cruise  (2 pm Alaska Daylight Time)

Weather Data from the Bridge 
Sky Condition:  Partly Cloudy
Temperature:  15.8 ° C
Wind Speed: Light Wind
Barometric Pressure:  1018.7 mb
Humidity:  84%

August 5, 2013 is a Cloudy Day on the Oscar Dyson

August 5, 2013 is a Cloudy Day on the Oscar Dyson

Sun and Moon Data
Sunrise:  5:13 am
Sunset:  9:35 pm
Moonrise:  4:22 am
Moonset:  8:27 pm

Geographic Coordinates   ( 2pm Alaska Daylight Time)

Latitude:  59 ° 09.7 N Longitude:  141° 27.6 W
The ship’s position now can be found by clicking:  Oscar Dyson’s Geographical Position

Science and Technology Log

Processing the Catch
My last blog  post focused on mid-water trawling; this blog will focus on processing the catch.  When we process the catch, we are processing it in a scientific way, not a food production way.  The goal of any fish survey is to try to determine how many fish (in this case pollock) are in the sea  in order to establish sustainable fishing limits. Ideally, trawling allows scientists to randomly select a sample of pollock to measure a good representation of the pollock population.  The survey is undertaken in an ecologically friendly way with a focus to preserve as many fish as possible by releasing them alive back into the ocean. I will go through the steps of this process.

Step 1:  Sorting and  Measuring

Usually, fish brought in with the trawl net are placed directly on the table.  If the catch is especially large, it may be weighed first by attaching a scale to a crane, and then attaching the load to the scale.  The entire catch is weighed so the scientists can use the length and gender data taken from the sample to extrapolate for the entire catch.  Then a sample (ideally 300 pollock) are kept to process and the rest are released.  This data is combined with the acoustics data to estimate the size of the entire stock.

Delivering Fish From Trawling Net to Table

Delivering Fish From Trawling Net to Table

Fish are emptied out of the net and onto the table outside of the fish lab. The number of  fish that land on the conveyor belt can be controlled by raising the table and opening the door.  The fish on the conveyor belt are separated by species.  Although in the catch there are often many types of species of sea animals present,  the focus of this blog will be the pollock that are caught.

An Interested Observer Checks out the Pollock on the Conveyor Belt

An Interested Observer Checks out the Pollock on the Conveyor Belt

In the video clip, the vast majority of the fish are adult pollock, but sometimes there are a variety of age stages;  Age 0, Age 1, and Adult are what we have seen.  Pollock are sorted by age, gathered into baskets, and weighed.  Age 0 and Age 1 pollock are weighed and then measured with the icthystick, a magnetic fish measuring board, from the head to the fork in the tail.  The icthystick is connected to a computer that automatically records the data.  (The icthystick below shows how the length of capelin, a prey of pollock, are measured and recorded; the method is the same pollock).

Weighing the Small Pollock and Capelin

Weighing the Small Pollock and Capelin

Capelin on Icthystick

Capelin on Icthystick

Capelin Measurements on Computer Screen

Capelin Measurements on Computer Screen

Step 2:  Sexing

Each age group has a somewhat different protocol for processing.  Counts and measurements of weight and length are taken for the smaller pollock (and capelin).  The larger pollock are grouped by sex. To do this, the abdomen is sliced open with a scalpel, the innards are pushed aside, and ovaries or testes are identified.  After determining the sex of the fish,  its length is measured with the icthystick.  Finally, a subsample of fish are set aside for otolith removal.  As we process a catch, samples of fish and other species are collected for various off-board scientists.  For example, Age 0 pollock are kept for one scientist;  ovaries from mature pollock for another.

Identifying Pollock Sex and Maturity

Identifying Pollock Sex and Maturity

Sometimes it is difficult to tell the testes from the ovaries.  Generally, both are paired organs that lie along the vertebrae under the guts (stomach, liver, intestines).  The ovaries tend to be fuller and more brightly colored; the testes, stringier and paler.  However, these organs can vary somewhat depending on the maturity of the fish.  Below are examples of the organs from fish that have not yet spawned (photos courtesy of Story Miller, TAS 2010).

These are the testes of a pre-spawning male

Testes of a Pre-Spawning Male Pollock (bottom right)

These are ovaries in the pre-spawning stage

Ovaries of a Pre-Spawning Female Pollock (center)

Step 3:  Removing Otoliths

Otoliths are made of calcium carbonate and are located directly behind the brain of bony fishes. They are involved in the detection of sound and the process of hearing.  The age of the fish can be established by counting the annuli (small ridges on the otoliths) much like one does when counting tree rings.  This age data allows scientists to estimate growth rates, age at maturity, and exposure to various environmental conditions.

Removing Otoliths from Pollock

Removing Otoliths from Pollock

The otoliths are brought to Seattle for more detailed analysis, so after extracting them from the pollock, they are placed in jars with a preservative called glycerol thymol.  The jars have bar codes on the side so that the otoliths are linked to the fish’ weight, length and sex.  These results will be used to correspond length to age in the stock assessment report.

Personal Log Accomplishment

Continuing with Maslow’s hierarchy of needs, I will discuss some of the ways that the need of feelings of accomplishment are met on the Oscar Dyson.  

A Version of Maslow's Hierarchy of Needs
A Version of Maslow’s Hierarchy of Needs
The goal of the Oscar Dyson crew is to safely and successfully navigate the ship through the Gulf of Alaska transects collecting and processing pollock.  As of Saturday, August 3 on this mission, we have traveled almost 3000 nautical miles, traversed through 33 transects and completed 26 Aleutian Wing Trawls, 6 Poly Nor’eastern Bottom Trawls, and 6 Methots.  We have measured and recorded data for 4,387 fish;  2,696 of these were pollock.  We have also collected 334 otoliths.  These numbers give the team a sense of accomplishment, knowing that they have contributed to the data and information processing to promote sustainable fishing practices.  Check out this link, the NOAA FishWatch webpage that provides information on sustainable fishing practices.

Did You Know?

Married couples can work together aboard the Oscar Dyson.  Kristin and Vince met in graduate school at the University of Florida where they were working on Master’s Degrees in Fisheries and Aquatic Science.  They were collaborating on a project that focused on river systems in Florida.  After getting married and working in labs at both the University of Maryland and Oregon State, they applied for Survey Technician positions with NOAA.  Kristen and Vince work opposite shifts on the Oscar Dyson; Kristen works mornings and Vince works evenings.  As survey technicians they are responsible for the calibration and deployment of various data acquisition systems such as the Scientific Computer System (SCS) that is constantly monitoring information such as air temperature, sea temperature, salinity, chlorophyll levels and weather.  Kristen and Vince work as liaisons between the science team and the NOAA Corps.
Vince and Kristen, Oscar Dyson Survey Technicians

Vince and Kristen, Oscar Dyson Survey Technicians

Something to Think About: 

So far we have discussed the following invertebrate animal phyla:  Porifera and Cnideria.  Today’s episode of Trawling Zoology features other interesting representatives of the invertebrate animal kingdom:  Annelida, Mollusca, Arthropoda, and Echinodermata that have turned up in our catches.

Phylum Annelida-from the Latin word anulus meaning “little ring”

Annelids are segmented worms that have a linear series of external segments divided by septa (walls between segments) that house serially repeated nervous, muscle, and excretory systems.  Their anterior segments contain jaws, eyes, and cirri (small feelers that help with feeding).  Filter-feeding marine annelids capture bacteria and feed selectively on sediment particles within tubes buried in sand or mud.

Polychaete from the Phylum Annelida  (found in a bottom trawl)

Polychaete from the Phylum Annelida (found in a bottom trawl)

Phylum Mollusca-from the Latin word mollis meaning “soft”

Mollusca is one of the most diverse groups of animals on the planet, with at least 50,000 living species (and more likely around 200,000). It includes such familiar organisms as sea snails, octopuses, squid, clams, and chitons, all of which we have seen on this mission.  They all have soft bodies which typically have a “head” and a “foot” region.  Often their bodies are covered by a hard exoskeleton, as in the shells of snails and clams or the plates of chitons.  Squid and octopuses have small internal shells.

Members of the Squid Family, Gonotopsis borealis, the Armhook Squid

Members of the Squid Family, Gonotopsis borealis, the Armhook Squid

Hermit Crabs (Arthropods) Inhabiting the Shells of Mollusks

Hermit Crabs (Arthropods) Inhabiting the Shells of Mollusks

Phylum Arthropoda-from the combination of Greek words arthron meaning “jointed” and pous meaning “feet”

The Phylum Arthropoda includes organisms such as insects, spiders, and crustaceans (crabs and shrimp).  The vast majority of sea dwelling arthropods are crustaceans.  For example, the hermit crabs emerging from the mollusk shells in the picture above are members of the most abundant family on Earth, the arthropods.  Arthropods have an exoskeleton of a tough compound called chitin that forms a rigid armor with joints in between.  This outer shell provides the structure against which arthropod muscles pull, reduces water loss, and protects them from environmental dangers.  Below are other examples of arthropods found frequently in trawls.

Isopods (The Cockroaches of the Sea) among Krill, another type of Arthropod

Isopods (The Cockroaches of the Sea) among Krill, another type of Arthropod

Phylum Echinodermata-from the combination of Greek words echinos meaning “spiny” and derma meaning “skin”

The adults are recognizable by their (usually five-point) radial symmetry, and include such well-known animals as starfish, sea urchins, sand dollars, and sea cucumbers.  Echinoderms are found at every ocean depth and contains about 7000 living species. Echinoderms are also the largest phylum that has no freshwater or terrestrial (land-based) representatives. Two unique characteristics of this phylum are the ability to regenerate tissues and their ossified limestone exoskeletons.

Various Starfish found in a Bottom Trawl

Various Starfish found in a Bottom Trawl

Jason Moeller: June 28, 2011

NOAA TEACHER AT SEA
JASON MOELLER
ONBOARD NOAA SHIP OSCAR DYSON
JUNE 11 – JUNE 30, 2011

NOAA Teacher at Sea: Jason Moeller
Ship: Oscar Dyson
Mission: Walleye Pollock Survey
Geographic Location: Whale Pass
Date: June 28-29, 2011

Ship Data
Latitude: 58.01 N
Longitude: -152.50 W
Wind: 23.95 knots
Surface Water Temperature: 9.4 degrees C
Air Temperature: 10.8 degrees C
Relative Humidity: 71%
Depth: 177.72 m

Personal Log

Welcome back, explorers!

Due to the injury to the deck hand, we are done fishing. Our trip has been cut a day short and we are now headed back to Kodiak. We should arrive tomorrow morning, and I will fly back home on the 30th.

The shortest route to Kodiak was through Whale Pass, a break in Kodiak Island. The pass made for some spectacular scenery.

The entrance to Whale Pass

The entrance to Whale Pass, from the back of the Oscar Dyson

Steep hills rolling down into the water were a common sight in the pass.

Steep hills rolling down into the water were a common sight in the pass.

nav point

An island with a navigational marker in whale pass.

mountain 1

There were some spectacular views of the mountains in the pass as well.

Mountains 2

Another view of the mountains.

Mountain 3

Another view of the mountains.

Mountain

And another...

mountain

Last one, I promise! We all liked the shape of this one.

waterfall

A waterfall drops away into the ocean.

The coolest part of the pass, though, is definitely the wildlife. We saw sea otters everywhere! Unfortunately, they were so fast and at a great enough distance that the following shot is the only decent one I was able to take.

otter

A sea otter at Whale Pass.

We also saw an animal that I have been hoping to see for a long time.

killer whales

Sorry about the grainy image, but it is the only one of the Orcas we were able to get.

We also saw a puffin, but it moved so quickly that there was no hope at a photo for it. Bummer. Several humpback whales were also spotted, along with numerous gulls and other seabirds.

Science and Technology Log

Today, lets talk about krill!

What are krill, you ask? They’re animals in the Phylum Arthropoda, which means they’re related to insects, spiders, crabs, lobsters, etc. They have jointed legs and an exoskeleton, are usually a couple of centimeters in length, and are reddish/orange-ish in color. They can often be found in dense schools near the surface of the water, and play an important role in the ecosystem as a source of food for lots of larger animals (like fish, whales, & penguins).

I’ve mentioned the two types of trawl gear that we use to catch fish, but if we want to catch smaller things like plankton, the mesh on those nets is way too small. Therefore, we use a third type of trawl called the Methot which has very fine mesh to corral the plankton down into a collection container at the end of the net. In addition to having a hard container at the end — as opposed to just a bag/codend that you see in the fish trawls — the Methot trawl also has a large metal frame at the beginning of the net. Check out the photos below.

The Methot trawl being taken from the water. Note the square frame.

container

The container that collects all of the plankton in the net.

After the net is brought back on deck, one of the fishermen or deck hands brings the container of krill into the fish lab. The first thing we do is dump the container into a sieve or a bucket and start picking out everything that isn’t krill. The two most common things that are collected (besides krill) are gelatinous animals (like jellyfish & salps) and larval fish. The fish get weighed (as one big unit, not individually) and then frozen for someone to look at later on.

fish

The larval fish that we separated from one plankton tow.

After sorting the catch, we’re left with a big pile of krill, which gets weighed. We then take a small subsample from the big pile of krill (it’s a totally random amount depending on how much we scoop out!) and then weigh the subsample. Then the fun begins, as I’m the one that does this job; I get to count every single individual krill in the subsample. Tedious work. All of the data is then entered into the computer system, and the krill and anything else that we’ve caught (besides the larval fish) are thrown back into the water.

Tammy sorts through the pile of krill.

Tammy sorts through the pile of krill.

counting krill

How many individual krill are in this picture?

Species Seen

Northern Fulmar
Gulls
Puffin
Humpback Whales
Killer Whale!!!
Sea Otters!!!

Reader Question(s) of the Day!

Q. What has been your favorite thing about this trip so far?

A. I’ve been asked this question several times over the course of the last few weeks, but I’ve waited until the end to answer it.

Truth be told, it’s almost impossible to pick a favorite thing that I’ve seen or done. There are so many candidates! Exploring the Buskin River and seeing bald eagles before we set sail was a blast! Eating fresh caught salmon for the first time was a great experience, as it just melted in my mouth. Leaving shore for the first time was a lot of fun, as there is no feeling like the salt air blowing past your face at the front of a boat. Trying to take pictures of flying birds with a digital camera was a challenge, and we all had a good time laughing at the blurred images. Getting better at photography is something I’ve always wanted to do, and I feel like I have improved that. The first fish lab with the sleeper shark was great! Working in the fish lab, as messy as it was, was also a lot of fun! The XBT prank that was pulled on me was one of the best executed pranks I’ve ever seen, and it was hilarious! Hanging out and reading Martin’s Game of Throne series during breaks with my fellow scientists was a lot of fun as well, as it was just like a book club. Today’s ride through Whale Pass with the otters, whales, and mountains was exactly what I dreamed Alaska would be like.

The scientists sense of humor also made it an enjoyable trip. For example, this is what happens when you play around with the net camera for too long.

Cam Trawl Dinner

See what I mean?

That being said, if I was absolutely forced to pick a favorite memory, it would probably the impromptu fishing trip at Sand Point. You know you love your job when you decide to keep going at it on your day off.

There will be one last log posted, so if you have questions please send them to me at jmoeller@knoxville-zoo.org!