Kacey Shaffer: Fish Scales. Fish Tales. August 8, 2014

NOAA Teacher at Sea

Kacey Shaffer

Aboard NOAA Ship Oscar Dyson

July 26 – August 13, 2014

 

Mission: Walleye Pollock Survey

Geographical Location: Bering Sea

Date: August 8, 2014
Weather information from the Bridge:

Air Temperature: 11° C

Wind Speed: 27 knots

Wind Direction: 30°

Weather Conditions: High winds and high seas

Latitude: 60° 35.97 N

Longitude: 178° 56.08 W
Science and Technology Log:

If you recall from my last post we left off with fish on the table ready to be sorted and processed. Before we go into the Wet Lab/Fish Lab we need to get geared up. Go ahead and put on your boots, bibs, gloves and a jacket if you’re cold. You should look like this when you’re ready for work…

 

This is the gear you'll need in the Wet Lab. It can get pretty slimy in there! (Photo Credit: Emily)

This is the gear you’ll need in the Wet Lab. It can get pretty slimy in there! (Photo Credit: Emily)

The first order of business is sorting the catch. We don’t have a magic net that only catches Pollock. Sometimes we pick up other treats along the way. Some of the cool things we’ve brought in are crabs, squid, many types of jellyfish and the occasional salmon. One person stands on each side of the conveyor belt and picks these other species out so they aren’t weighed in with our Pollock catch. It is very important that we only weigh Pollock as we sort so our data are valid. After all the Pollock have been weighed, we then weigh the other items from the haul. Here are some shots from the conveyor belt.

 

Kacey lifts the door on the table so the fish will slide down onto the conveyor belt. This is when other species are pulled out. (Photo Credit: Sandi)

Kacey lifts the door on the table so the fish will slide down onto the conveyor belt. This is when other species are pulled out. (Photo Credit: Sandi)

At the end of the conveyor belt, Pollock are put into baskets, weighed and put into the sorting bin. (Photo Credit: Sandi)

At the end of the conveyor belt, Pollock are put into baskets, weighed and put into the sorting bin. (Photo Credit: Sandi)

Not every single fish in our net is put into the sorting bin. Only random selection from the catch goes to the sorting bin. The remaining fish from the haul are returned back to the sea. Those fish who find themselves in the sorting bin are cut open to determine their sex. You can’t tell the sex of the fish just by looking at the outside. You have to cut them open, slide the liver to the side and look for the reproductive organs. Males have a rope-like strand as testes. Females have ovaries, which are sacs similar to the stomach but are a distinctly different color.

 

This is the sorting bin. Can you guess what Blokes and Sheilas means?

This is the sorting bin. Can you guess what Blokes and Sheilas means?

The white, rope-like structure is the male reproductive organ.

The white, rope-like structure is the male reproductive organ.

The pinkish colored sac is one of the female's ovaries. It contains thousands of eggs!

The pinkish colored sac is one of the female’s ovaries. It contains thousands of eggs!

Kacey uses a scalpel to cut the fish. She slides the liver out and looks for the reproductive organs. Is it a male or female? (Photo Credit: Darin)

Kacey uses a scalpel to cut the fish. She slides the liver out and looks for the reproductive organs. Is it a male or female? (Photo Credit: Darin)

Okay, no more slicing open fish. For now! The next step is to measure the length of all the fish we just separated by sex. One of the scientists goes to the blokes side and another goes to the sheilas side. We have a handy-dandy tool used to measure and record the lengths called an Ichthystick. I can’t imagine processing fish without it!

The Ichthystick is used to record the length of fish. A special tool held in the hand has a magnet inside that makes a connection with a magnet strip inside the board. It automatically registers a length and records it in a computer program called Clams

The Ichthystick is used to record the length of fish. A special tool held in the hand has a magnet inside that makes a connection with a magnet strip inside the board. It automatically registers a length and records it in a computer program called Clams

Kacey measures the length of a male with the Ichthystick. She holds the tool in her right hand and places it at the fork in the fish’s tail. A special sound alerts her when the data is recorded. (Photo Credit: Darin)

Kacey measures the length of a male with the Ichthystick. She holds the tool in her right hand and places it at the fork in the fish’s tail. A special sound alerts her when the data is recorded. (Photo Credit: Darin)

That is the end of the line for those Pollock but we still have a basket waiting for us. A random sample is pulled off the conveyor belt and set to the side for another type of data collection. The Pollock in this special basket will be individually weighed, lengths will be taken and a scientist will determine if it is a male or female. Then we remove the otoliths. What are otoliths? They are small bones inside a fish’s skull that can tell us the age of the fish. Think of a tree and how we can count the rings of a tree to know how old it is. This is the same concept. For this special sample we remove the otoliths, which are labeled and given to a lab on land where a scientist will carefully examine them under a microscope. The scientist will be able to connect the vial containing the otoliths to the other data collected on that fish (length, weight, sex) because each fish in this sample is given a unique specimen number. This is all part of our mission, which is analyzing the health and population of Pollock in the Bering Sea!

Kacey scans a barcode placed on an otolith vial. Robert is removing the otoliths from each fish and Kacey places them in the vial. It is important to make sure the otoliths are placed in the vial that corresponds to the fish Robert measured. (Photo Credit: Emily)

Kacey scans a barcode placed on an otolith vial. Robert is removing the otoliths from each fish and Kacey places them in the vial. It is important to make sure the otoliths are placed in the vial that corresponds to the fish Robert measured. (Photo Credit: Emily)

 

Kacey removes an otolith from a fish Robert cut open. The otoliths are placed in the vial Kacey is holding. (Photo Credit: Emily)

Kacey removes an otolith from a fish Robert cut open. The otoliths are placed in the vial Kacey is holding. (Photo Credit: Emily)

At this point we have just about collected all the data we need for this haul. Each time we haul in a catch this process is completed. As of today, our survey has completed 28 hauls. Thank goodness we have a day shift and a night shift to share the responsibility. That would be a lot of fish for one crew to process! For our next topic we’ll take a look at how the data is recorded and what happens after we’ve completed our mission. By the way, “blokes” are males and “sheilas” are females. Now please excuse us while we go wash fish scales off of every surface in the Wet Lab, including ourselves!

Personal Log:

Just so you know, we’re not starving out here. In fact, we’re stuffed to the gills – pun completely intended. Our Chief Steward Ava and her assistant Adam whip up some delicious meals. Since I am on night shift I do miss the traditional breakfast served each morning. Sometimes, like today, I am up for lunch. I’m really glad I was or I would have missed out on enchiladas. That would have been a terrible crisis! Most people who know me realize there is never enough Mexican food in my life! Tacos (hard and soft), rice and beans were served along with the enchiladas. Each meal is quite a spread! If I have missed lunch I’ll grab a bowl of cereal to hold me over until supper. I bet you’ll never guess we eat a lot of seafood on board. There is usually a fish dish at supper. We even had crab legs one night and fried shrimp another. Some other supper dishes include pork chops, BBQ ribs, baked steak, turkey, rice, mashed potatoes, and macaroni and cheese plus there are always a couple vegetable dishes to choose from. We can’t forget about dessert, either. Cookies, cakes, brownies or pies are served at nearly every meal. It didn’t take long for me to find the ice cream cooler, either. What else would one eat at midnight?!

Ava and Adam are always open to suggestions as well. Someone told Ava the night shift Science Crew was really missing breakfast foods so a few days ago we had breakfast for supper. Not only did they make a traditional supper meal, they made a complete breakfast meal, too! We had pancakes, waffles, bacon, eggs, and hashbrowns. It was so thoughtful of them to do that for us, especially on top of making a full meal for the rest of the crew. Thanks Ava and Adam!

There are situations where a crew member might not be able to make it to the Mess during our set serving schedule. Deck Crew could be putting a net in or taking it out or Science Crew could be processing a catch. We never have to worry, though. Another great thing about Ava and Adam is they will make you a plate, wrap it up and put it in the fridge so you have a meal for later.

Like I said, we’re not going hungry any time soon! Here are some shots from the Mess Deck (dining room).

Mess Deck on the Oscar Dyson.

Mess Deck on the Oscar Dyson.

Mess Deck on the Oscar Dyson. Can you guess why there are tennis balls on the legs of the chairs?

Mess Deck on the Oscar Dyson. Can you guess why there are tennis balls on the legs of the chairs?

There are always multiple options for every meal. If you’re hungry on this ship you must be the pickiest eater on Earth!

There are always multiple options for every meal. If you’re hungry on this ship you must be the pickiest eater on Earth!

Did you know?

Not only are otoliths useful to scientists during stock assessment, they help the fish with balance, movement and hearing.

Johanna Mendillo: From Russia with Love… August 1, 2012

NOAA Teacher at Sea
Johanna Mendillo
Aboard NOAA Ship Oscar Dyson
July 23 – August 10, 2012

Mission: Pollock Survey
Geographical area of the cruise: Bering Sea
Date: Wednesday, August 1, 2012

Location Data from the Bridge:
Latitude: 62  18’ N
Longitude: 178 51’ W
Ship speed:  2.5 knots (2.9 mph)

Weather Data from the Bridge:
Air temperature: 9.5C (49.1ºF)
Surface water temperature: 8.5C (47.3ºF)
Wind speed: 9.1 knots (10.5 mph)
Wind direction: 270T
Barometric pressure:  1001 millibar (0.99 atm)

Science and Technology Log:

In the last few days, we have crossed into the Russian Exclusive Economic Zone, sampled, and are now back on the U.S. side!   Unfortunately, students, there was no way for my passport to get stamped.  There was no formal ceremony, and we will cross back and forth many times in the next two weeks as we do our science transects, collecting Pollock, but the science team took a moment to celebrate— and I snapped a quick picture of the computer screen.

Crossing into Russia!

Crossing into the Russian Exclusive Economic Zone!

I would now like to introduce you to one of the most simple and valuable tools we use on board to measure a sample of Pollock- the Ichthystick.

The one... the only... Icthystick!

The one… the only… Ichthystick!

First, some background.  Each day we “go fishing” 2-4 times with our mid-water and bottom trawls. “Trawling” simply means dragging a large net through the water to collect fish (and you will learn more about the different types of nets we use quite soon).  After the trawl, we bring the net back on board and see what we have caught!

There are many types of data we collect from each catch- first and foremost, the total weight of the catch and the numbers and masses of any species we catch in addition to pollock.  So far, we have collected salmon, herring, cod, lumpsuckers, rock sole, arrowtooth flounder, Greenland turbot, and jellyfish on my shifts!  Our focus, though, of course, is pollock.  For pollock-specific data, we keep a sub-sample of the catch, usually 300-500 fish, for further analysis, and we release the rest back into the ocean.

From this sub-sample, I help the scientists collect gender and length data.  As I mentioned in my last post, we also collect otoliths from the sub-samples so that the age structure of the population can be studied back in Seattle.  The most straightforward and obvious data, though, is simply measuring the length of the fish, which takes us back to the wonderful contraption known as the Ichthystick!

Now, scientists cannot determines the age of a pollock simply from measuring its length- there are many factors that determine how fast a fish can grow, such as access to food, space, its overall health, environmental conditions, etc.  But, by collecting length data and combining it with age data from otoliths, scientists can begin to see the length ranges at each age class and the overall “big picture” for the population emerges.

And again, once the age structure and population size of pollock in the Bering Sea are determined for a certain year, management decisions can be made, commercial fish quotas are set for the upcoming fishing season, and there will still be a suitable population of fish left in the ocean to reproduce and keep the stocks at sustainable levels for upcoming years.

The Icthystick logo... designed by scientist Kresimir himself!

The Ichthystick logo… designed by scientist Kresimir!

So, it clearly does not make much sense to measure pollock with a ruler, paper, and pencil.  To measure hundreds of fish at a time, the NOAA team has developed a simple yet ingenious measuring tool, powered by magnets, and transmitted electronically back to their computers for easy analysis- the Ichthystick!

The Ichthystick may simply look like a large ruler, but it consists of a sensor and electronic processing board mounted in a protective (& waterproof!) container.  Inside, the sensor processes, formats and transmits the measurement values of each fish to an external computer that collects and stores the data.

 

Here I am...measuring away!

Here I am…measuring away!

Interestingly, the board works with magnets and makes use of the property of magnetostriction.

With magnetostriction, magnetic materials change shape when exposed to a magnetic field.  Magnetostrictive sensors can use this property to measure distances by calculating the “time of flight” for a sonic pulse generated in a magnetic filament when a measurement magnet is placed close to the sensor.  Here, in the picture, I am placing the fish along the sensor and holding the measurement magnet in my right hand.

Do you see stylus in my right hand?

Do you see stylus (containing the magnet) in my right hand?

To determine the distance to the measurement magnet, the elapsed time between when I touch the magnet to the board to generate the ultrasonic pulse and when the pulse is detected by the sensor is recorded– and that time is converted to a distance (using the speed of sound in that material), which is equal to the fish’s length!

Now, the “measurement magnet” is referred to as the “stylus”, and it is a little white plastic piece, the size of a magic marker cap, which contains the magnet embedded into the bottom.  You simply strap the stylus onto your index finger with velcro (so that the north pole of the magnet is facing down toward the sensor) and are ready to begin measuring!  The magnet inside is a small neodymium magnet, chosen because it has a very strong magnetic field.  Each time a measurement is recorded, a chime sounds, and I know I can go on to measuring my next fish!  At this point, I have measured a few thousand fish!

Personal Log:

Let’s continue our tour aboard the Oscar Dyson!  I think it is fair to say that scientific research makes one hungry!  I have enjoyed meeting Tim and Adam, the stewards (chefs) onboard the Dyson, devouring their delicious meals, and spending time talking with the officers and crew in the galley (kitchen) and mess (dining hall).  As you can see from my picture, the first thing you notice are the tennis balls on the bottoms of the chairs!  Why do you think they are there?

Look on the floor...

Look on the floor…

As in most things related to ship design, planning for rough seas is paramount!   So, in addition to tennis balls, which stop the chairs from sliding around, there are bungee cords that attach the chairs to the floor.  The dishes are also strapped down and most items are in boxes, bins, or behind closed doors.  But do not let that fool you— there is a LOT of food in there!  I have enjoyed many a midnight snack- fruit, yogurt, ice cream bars, cereal bars, cookies, and soup to name just a few.  In addition, there is a salad bar and a selection of leftover dinner items available to reheat each night.  Since I am on the 4pm-4am shift, I have been missing breakfast, and I have been told I must have at least one hot cooked-to-order meal before I depart!

Don't be late... or you will go hungry!

Don’t be late… or you will go hungry!

The Mess Rules!

The Mess rules!

I was a little surprised to see a mini-Starbucks on board too!  It is quite a setup, complete with pictures and directions on how to make each concoction:

Which kind would you order?

Which kind would you order?

Dennis, one of the Survey Technicians who works on the overnight shift with me, promised to make me a hazelnut latte if I could correctly predict the number of  pollock in a trawl, Price-Is-Right style.  I finally won a few nights ago….

Interestingly, there are no mechanisms in place to help the stewards cook in rough seas, but Adam assured me that he has never had a dinner for thirty slide off the grill and onto the floor!  Adam has been working in the NOAA fleet for over 10 yrs., including 7 yrs on the Miller Freeman, the precursor to the Oscar Dyson.  He has been onboard the Dyson for almost a year.  Tim has just joined the Dyson on this cruise and was previously in our home state— aboard the Delaware out of Woods Hole, Massachusetts!  Before joining NOAA, he worked on several supply ships that sailed across the world.  Each has been quite friendly and helpful as I learn to navigate my way around both the ship and my new schedule.  One of our frequent conversations is menu planning and the all-important-dessert on the schedule for each night.  So far, I have enjoyed apple cobbler, pineapple upside down cake, snickers cake, carrot cake, brownie sundaes, oatmeal raisin cookies, and… Boston cream pie!

Assistant Steward Adam

Assistant Steward Adam

Chief Steward Tim

Chief Steward Tim

Tim and Adam's domain... the Galley!

Tim and Adam’s domain… the Galley!

One last Q: How many dozens of eggs do you think Tim and Adam will go through on our 19-day cruise with 30 people on board?  Write your guess in the comment section and I will announce the answer in my next post…

Allan Phipps: Fish heads, fish heads, rolly polly fish heads…. July 31, 2012

NOAA Teacher at Sea
Allan Phipps
Aboard NOAA Ship Oscar Dyson
July 23 – August 11, 2012

Mission: Alaskan Pollock Mid-water Acoustic Survey
Geographical Area: Bering Sea
Date: July 31, 2012

Location Data
Latitude: N 61°39’29”
Longitude: W 117°55’90”
Ship speed: 11.7 knots (13.5mph)

Weather Data from the Bridge
Wind Speed: 26 knots (30mph)
Wind Direction: 044°
Wave Height: 4 meters (12 ft)
Surface Water Temperature: 8.2°C ( 46.8°F)
Air Temperature: 7.4°C (45°F)
Barometric Pressure: 994 millibar (0.98 atm)

Science and Technology Log:

Last blog, we learned about the different trawl nets and how the NOAA scientists are comparing those nets while conducting the mid-water acoustic pollock survey.  We left off with the fish being released from the codend onto the lift table and entering the fish lab.  Here is where the biological data is collected.

Walleye pollock on the sorting table. Various age groups are seen here, including one that is 70cm long and may be over 12 years old! Most are 2 to 4 year olds.

The fish lab is where the catch is sorted, weighed, counted, measured, sexed, and biological samples such as the otoliths, or earbones,  are taken (more about otoliths later in this post).  First, the fish come down a conveyor belt where they are sorted by species (see video above).  Typically, the most numerous species (in our case pollock) stay on the conveyor and any other species (jellyfish and/or herring, but sometimes a salmon or two, or maybe even something unique like a lumpsucker!), are put into separate baskets to weigh and include in the inventory count.  In the commercial fishing industry, these species would be considered bycatch, but since we are doing an inventory survey, we document all species caught.  Here are some pictures of others species caught and included in the midwater survey.

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The goal of each trawl is to randomly select a sample of 300 pollock to measure as a good representation of the population (remember your statistics!  Larger sample sizes will give you a better approximation of the real population).  If more than 300 pollock are caught, the remainder are weighed in baskets and quickly sent back to sea.  All of the catch is weighed so the scientists can use the length and gender data taken from the sample to extrapolate for the entire catch.  This data is combined with the acoustics data to estimate the size of the entire fishery (more on acoustic data in a future post). Weights are entered via touch screen into a program (Catch Logger for Acoustic Midwater Surveys – CLAMS) developed by the NOAA scientists onboard.

The CLAMS display showing that I am “today’s scientist.”

The 300 pollock are sexed to determine the male/female ratio of this randomly selected portion of the population.  Gender is determined by making an incision along the ventral side from posterior to anterior beginning near the vent.  This exposes the internal organs so that either ovaries or testes can be seen.  Sometimes determining gender is tricky since the gonads look very different as fish pass through pre-spawning, spawning, or post-spawning stages.  When we determine gender, the fish are put into two separate hoppers, the one for females is labeled “Sheilas” and the hopper for males is labeled “Blokes.”

Making incision to determine gender on pollock sample.

Hopper for female pollock ready to be measured with the Ichthystick and entered into CLAMS.

We use an Ichthystick to then measure the males and females separately to collect length data for this randomly selected sample.  Designed by NOAA Scientists Rick and Kresimir, the Ichthystick very quickly measures lengths by using a magnet placed at the fork of the fish’s tail (when measuring fork-length).  This sends a signal to the computer to record the individual fish’s length data immediately into a spreadsheet and the software creates a population length distribution histogram in real-time as you enter data.

The Ichthystick with fingertip magnet used to quickly measure and enter length data into CLAMS.

A randomly selected subset of 40 pollock get individually weighed, length measured, sexed, evaluated for gonadal maturity and have the otoliths removed.  Otoliths (oto = ear, lithos = bone) are calciferous bony structures in the fish’s inner ear.  These are used to determine age when examined via cross-section under a dissecting scope.  The number of rings corresponds to the age of the pollock, similar to rings seen in trees. The otoliths are taken by holding the fish at the operculum and making an incision across the top of the head to expose the brain and utricle of the inner ear.  The otolith is found inside the utricle.  Forceps are used to extract the otoliths, which are then washed and put in individual bar-coded vials with glycerol-thymol solution to preserve them for analysis back at the Alaska Fisheries Science Center.

Incision across the skull revealing the otoliths on either side of the brain stem.

One otolith from a Walleye pollock.

Watch this short video to see what the entire process of data collection looks like.

So… why collect all of this data?  How is this data analyzed and used?  Stay tuned to my next blog!

Personal Log:

Well, I can officially say… the honeymoon is over.  The Bering Sea had been so extremely kind to us with several days of great weather while we had a high pressure system over us.  We enjoyed spectacular sunrises and sunsets, cloudless days and calm seas.

Sunny skies and calm seas on the Oscar Dyson.

Now… we have a low pressure system on top of us.  Last night, we experienced 35 knot winds and 12 foot seas.  I have spent a lot of time in my room in the past 24  hours…  Late this morning, the sun came out and the winds calmed down, but the barometric pressure was still very low (around 990 mbars) which basically meant we were in the center of the low pressure system (similar to the eye of a hurricane, but not as strong… thank goodness!).  We had a few hours relief, but we are back to pounding through the waves as the wind picks back up.  It will be another long and sleepless night for this landlubber…

On a positive note, we did see two Laysan Albatrosses (Phoebastria immutabilis) from the Bridge as the winds began to kick up.  They seemed to really enjoy the high winds as they soared effortlessly around the ship.  The Officer on Deck (OOD) also said he saw a humpback breaching, but by the time I got up to the Bridge, it had moved on…

Next blog, I will share pictures of my room, the galley, “the cave,” the Bridge, etc.  Right now, I am just trying to hold on to my mattress and my stomach…