Cathrine Prenot: Sea Speak. July 25, 2016

NOAA Teacher at Sea
Cathrine Prenot
Aboard Bell M. Shimada
July 17-July 30, 2016

 

Mission: 2016 California Current Ecosystem: Investigations of hake survey methods, life history, and associated ecosystem

Geographical area of cruise: Pacific Coast from Newport, OR to Seattle, WA

Date: Sunday, July 24, 2016

Weather Data from the Bridge

Lat: 47º32.20 N
Lon: 125º11.21 W
Speed: 10.4 knots
Windspeed: 19.01 deg/knots
Barometer: 1020.26 mBars
Air Temp: 16.3 degrees Celsius
Water Temp: 17.09 degrees Celsius


Science and Technology Log

Typical evening view from the flying bridge of the Bell M. Shimada

Typical evening view from the flying bridge of the Bell M. Shimada

We have been cruising along watching fish on our transects and trawling 2-4 times a day. Most of the trawls are predominantly hake, but I have gotten to see a few different species of rockfish too—Widow rockfish, Yellowtail rockfish, and Pacific Ocean Perch (everyone calls them P.O.P.)—and took their lengths, weights, sexes, stomachs, ovaries, and otoliths…

…but you probably don’t know what all that means.

The science team sorts all of the catch down to Genus species, and randomly select smaller sub-samples of each type of organism. We weigh the total mass of each species. Sometimes we save whole physical samples—for example, a researcher back on shore wants samples of fish under 30cm, or all squid, or herring, so we bag and freeze whole fish or the squid.

For the “sub samples” (1-350 fish, ish) we do some pretty intense data collection. We determine the sex of the fish by cutting them open and looking for ovaries or testes. We identify and preserve all prey we find in the stomachs of Yellowtail Rockfish, and preserve the ovaries of this species’ females and others as well. We measure fish individual lengths and masses, take photos of lamprey scars, and then collect their otoliths.

Fish Otolith showing concentric growth rings from here.

Otoliths are hard bones in the skull of fish right behind the brain. Fish use them for balance in the water; scientists can use them to determine a fish’s age by counting the number of rings. Otoliths can also be used to identify the species of fish.

Here is how you remove them: it’s a bit gross.

Otolith instructions from here.

Cod, Redfish, and Hake otoliths from here.

 

A bigger fish species does not necessarily mean a larger otolith. From here.

If you want to check out an amazing database of otoliths, or if you decide to collect a few and want to see what species or age of fish you caught, or if you are an anthropologist and want to see what fish people ate a long time ago? Check out the Alaska Fisheries Science Center—they will be a good starting spot.  You can even run a play a little game to age fish bones!

Pacific Ocean Perch, or P.O.P.

Pacific Ocean Perch, or P.O.P.

 

Personal Log

I haven’t had a lot of spare time since we’ve been fishing, but I did manage to finagle my way into the galley (kitchen) to work with Chief Steward Larry and Second Cook Arlene. They graciously let me ask a lot of questions and help make donuts and fish tacos!  No, not donut fish tacos.  Gross.

How to make friends and influence people

How to make friends and influence people

Working in the galley got me thinking of “ship jargon,” and I spent this morning reading all sorts of etymology.  I was interested to learn that the term crow’s nest came from the times of the Vikings when they used crows or raven to aid navigation for land.  Or that in the days of the tall ships, a boat that lost a captain or officer at sea would fly blue flags and paint a blue band on the hull—hence why we say we are “feeling blue.”  There are a lot more, and you can read some interesting ones here.

You can also click on Adventures in a Blue World below (cartoon citations 1 and 2).

TAS Cat Prenot 2016 cartoon4 v2

And here is a nautical primer from Adventures in a Blue World Volume 1:

A Nautical Primer part I from 2011 aboard the Oscar Dyson

A Nautical Primer from 2011 aboard the Oscar Dyson

 

Did You Know?

Working in the wet lab can be, well, wet and gross. We process hundreds of fish for data, and then have hoses from the ceiling to spray off fish parts, and two huge hoses to blast off the conveyor belt and floors when we are done. But… …I kind of love it.

Yay Science!

Yay Science!

Resources

Etymology navy terms: http://www.navy.mil/navydata/traditions/html/navyterm.html

Interestingly enough, the very words “Sea Speak” have a meaning.  When an Officer of the Deck radios other ships in the surrounding water, they typically use a predetermined way of speaking, to avoid confusion.  For example, the number 324 would be said three-two-four.

 

Cristina Veresan, Gone Fishin’, August 1, 2015

NOAA Teacher at Sea
Cristina Veresan
Aboard NOAA Ship Oscar Dyson
July 28 – August 16, 2015

Mission: Walleye Pollock Acoustic-Trawl survey
Geographical area of cruise: Gulf of Alaska
Date: Saturday, August 1, 2015

Data from the Bridge:
Latitude: 58° 39.0′ N
Longitude: 148° 045.8′ W
Sky: Broken clouds
Visibility: 10 miles
Wind Direction: W
Wind speed: 15 knots
Sea Wave Height: 3 feet
Swell Wave: 0 feet
Sea Water Temperature: 15.4° C
Dry Temperature: 13.8° C

Science and Technology Log

So, you might be wondering how our scientists know when it’s time to “go fishin’”? That is, how do they determine if there might be a significant concentration of pollock to deploy a trawl? The answer is acoustics! The ship is equipped with a multitude of acoustic transducers on the bottom of the ship, five of which are primarily used in the pollock population assessment. These transducers both send and receive energy waves; they transmit sound waves down to the ocean floor, which reflect back to the ship. However, if there are obstacles of a different density in the water (like fish), the signal bounces back from that obstacle. The amount of energy that pollock individuals of different lengths return is known to our scientists.

Chief Scientist Darin Jones studies the echogram

Chief Scientist Darin Jones studies the echogram and talks to the bridge

The real-time data from transducers is automatically graphed in what is called an echogram. When we are on our predetermined transect line, the scientist on watch analyzes the echograms to make the determination of when to trawl. The transducers are different frequencies. In general, the higher the frequency, the smaller the object it can detect. To make a final decision on fishing, the scientist must also coordinate with the officers on the bridge who take into account wind speed, wind direction, water currents, and ship traffic. Once we collect the trawl data, scientists use the catch information to assign a species and length designation to the echogram data in order to produce a pollock biomass or abundance estimate. In addition to the pollock we are targeting, we have caught salmon, cod, jellyfish, and a few different types of rockfish.

echogram

Each echogram is from a different frequency transducer

We often catch one type of rockfish, the Pacific Ocean perch (Sebastes alutus), which has a similar acoustic signature as pollock. On the ship, we call this fish POP, and they are difficult to handle because of the sharp spines on their dorsal fin, anal fin, head, and gill covers (operculum). You have to watch out for spine pricks when handling them! Their eyes usually bulge when they come up from depth quickly and gases escape, which is a form of barotrauma. One interesting fact about Pacific Ocean perch is that they are viviparous (give birth to live young); the male fish inserts sperm into the female fish and her egg is fertilized inside her body. These fish can also be incredibly long-lived, with individuals in Alaska reaching almost 100 years old. The Pacific Ocean perch fishery declined in the 1960’s-1970’s due to overfishing, but has since recovered due to increased regulation.

POP

You down with POP?! Yeah, you know me!

 

Allen Smith, Senior Survey Technician

Allen Smith, Senior Survey Technician

Shipmate Spotlight: Interview with Allen Smith

What is your position on the Oscar Dyson?
I am the Senior Survey Technician. It’s my second season in this role.

Where did you go to school?
There is no formal training for this position, but you do need a scientific/technical background. I have a BS in geology, and right after college, I worked in technical support for Apple.

What do you enjoy the most about your work?
My favorite part is meeting people and re-connecting with ones I already know. Different scientists rotate in and out and they are my contact with the outside world.

Have you had much experience at sea?
I have worked on ships since 2011. I worked on cruise ship as a cook then I joined NOAA and sailed on the NOAA ship Oscar Elton Sette in Hawai’i as a cook and then later joined the NOAA ship Oscar Dyson as a survey tech. I really wanted to get back into science so I made the switch.

Where do you do most of your work aboard the ship? What do you do?
The domain of the survey technician is the laboratory. We have wet, dry, chemical, and computer/electronics labs aboard the Oscar Dyson. I am responsible for the meteorological, oceanographic, and navigation data that the ship collects full-time. We also help visiting scientists to accomplish their missions using the ship’s resources, like deploying fishing gear, CTD, cameras, or other equipment. Sometimes we do special missions like last year when we went to the Bering Sea for an ice-associated seal survey and our ship had to break through sea ice. During scientific operations, I work a 12-hour shift everyday.

When did you know you wanted to pursue a marine career?
I grew up in Dallas, Texas, which is totally land-locked, so you could say I wanted a change.

What are your hobbies?
No time for hobbies at sea! Just kidding, I like photography and playing guitar and ukulele. When I am not at sea, I enjoy hiking and biking.

What do you miss most while working at sea?
Probably what I miss the most is being able to cook vegetarian meals for myself. 

What is your favorite marine creature?
The red-footed booby because they have so much personality and are very entertaining.

Inside the Oscar Dyson: The Galley

galley

The ship’s galley is always open

The galley is ship-speak for the kitchen and dining area. Our ship stewards (chefs) work really hard to prepare buffet-style meals three times a day. Breakfast is served from 7-8am, lunch from 11am-noon, and dinner from 5-6pm. There is also a salad bar and a soup available for lunch and dinner. One night we even had food popular in Hawai’i: Kalua Pork, ramen stir fry, and chicken katsu! You can also come in the galley 24 hours a day to get coffee, espresso, tea, water, and various snacks. There is even an ice cream freezer! You might notice the chairs in the galley have tennis balls on the ends of the legs, as well as tie downs attached to them; this is to prevent sliding during rough seas.

 Personal Log

One of the challenges of working on a moving platform is seasickness. Nausea can be really debilitating, and it prevents many people from enjoying time on the water. I am not prone to it, but I am aware it could still afflict me at any time. Luckily, we have had very calm seas, and I have felt great, even when typing on the computer or slicing up fish! I brought some anti-seasickness medication with me but I have not needed it yet. I also have some candied ginger with me that I have been enjoying, though not for medicinal purposes.

Good morning from the Oscar Dyson!

Feeling happy, not seasick!

The scenery this week has been incredible as we weave our way through the bays and fjords of the Kenai Peninsula. McCarty fjord, carved 23 miles into the coast, was very impressive. The fjord is flanked by massive green mountains and towering cliffs. This majestic landscape was carved by ancient glaciers. I have spotted a few bald eagles, and, with binoculars, one of the deck crew members saw a brown bear mama and two cubs. As much as I love the open ocean, it’s exciting to be close to shore, so we can enjoy Alaska’s dramatic vistas and wildlife.

I am loving life at sea!

glacier

McCarty Glacier comes out from the clouds

Melissa George: Scraping the Bottom-Dwellers, August 6, 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:  Tuesday, August 6, 2013

Current Data From Today’s Cruise  (9 am Alaska Daylight Time)

Weather Data from the Bridge 
Sky Condition:  Partly Cloudy
Temperature:  15° C
Wind Speed: 7 knots
Barometric Pressure:  1019.6 mb
Humidity:  90%

August 6, 2013: Partly Cloudy or Partly Mountainy?

August 6, 2013: Partly Cloudy or Partly Mountainy?

Sun and Moon Data
Sunrise:  5:15 am
Sunset:  9:33 pm
Moonrise:  5:33 am
Moonset:  8:45 pm

Geographic Coordinates   ( 9 am Alaska Daylight Time)

Latitude:  59 ° 20.4 N Longitude:  141° 16.6 W
The ship’s position now can be found by clicking:  Oscar Dyson’s Geographical Position

Science and Technology Log

Besides the mid-water trawling, information about the pollock population is gathered in other ways on the Oscar Dyson research vessel.  One of these ways is direct, monitoring the pollock by trawling in other parts of the water column; the other way is indirect, evaluating the prey that the pollock feeds on.

Bottom Trawling

Scientists use acoustics to locate the signal for the fish.  Sometimes this signal is noticed near the ocean floor.  In this case, the PolyNor’eastern (PNE) Bottom Trawl Net is used to trawl for fish.  This net is a large net equipped with rubber bobbins that allow it to get close to the benthic region of the ocean without dragging.

Poly Nor'Eastern Bottom Trawling Net

Poly Nor’Eastern Bottom Trawling Net

During this research expedition, we used the PNE net six times to survey pollock.  Often times these trawls brought up other interesting sea life, that were quickly assessed (identified, measured, and recorded) and returned to the ocean.  The majority of invertebrate sea animals such as poriferans (sponges), cnidarians (sea anemones), annelids (segmented worms), mollusks (barnacles), arthropods (hermit crabs hiding in mollusk shells), and echinoderms (sea urchins and starfish) were brought up in these hauls.  In addition, some interesting species of fish (see this blog’s Trawling Zoology segment below) were gathered in bottom trawls.

Miscellaneous Invertebrates from Bottom Trawl

Miscellaneous Invertebrates from Bottom Trawl

Large Lingcod Caught in Bottom Trawl

Large Lingcod Caught in Bottom Trawl

Using the Methot Trawl

We use the Methot trawling net to sample krill, a type of zooplankton that pollock feeds on.  On this voyage, the Methot was used 6 times as well.  The Methot is a single net with a large square opening or mouth. The net is deployed from the stern and towed behind the vessel.  Inside the Methot is a small removable codend where much of the catch is deposited.

Methot Net Lying on Trawl Deck

Methot Net Lying on Trawl Deck

Raising the Methot Net

Raising the Methot Net

Codend of Methot Overflowing with Krill

Codend of Methot Overflowing with Krill

The krill is measured and counted as well.  First, the water is drained out, then it is weighed, and a small sample is weighed and counted.

Lining Up and Counting Krill

Lining Up and Counting Krill

Bottom trawls and Methot trawls are both important aspects of the pollock survey.

Personal Log

Accomplishment

Continuing with Maslow’s hierarchy of needs, I will discuss the top part of the pyramid, how self-actualization, or being involved in creative endeavors to expand one’s full potential, are met on the Oscar Dyson.  

A Version of Maslow's Hierarchy of Needs

A Version of Maslow’s Hierarchy of Needs

Since I am an honorary member of the am science team, I am privy to many discussions between the scientists on the team regarding a variety of topics.   For example, one side project on the mission is to gather information regarding the abundance and distribution of euphausiids (krill) in the Gulf of Alaska.  This research project involves the use of a smaller “critter camera,” engineered and built by two of the MACE (Midwater Assessment and Conservation Engineering) group members, to take pictures of krill at various ocean depths and (ideally) reconcile its distribution with acoustic and Methot trawl data.  The goal of the project is to provide insight into the feeding conditions of pollock.  The discussions between group members involve postulating, speculating, testing, theorizing, analyzing, teaching, and questioning; clearly this meaty dialog  indicates that the process of science is an intellectually stimulating and creative endeavor.

Scientist Team Members--- Abigail, Patrick, and Kirsten---Engaged in a Stimulating Discussion

Scientist Team Members— Abigail, Patrick, and Kirsten—Engaged in a Stimulating Discussion

Did You Know?
One of the people who views my blogs before they are posted is the Executive Officer (2nd in Charge) of the crew on the Oscar Dyson.  His name is Chris and on this mission he is “augmenting” or filling in for another employee.  Chris administers the day-to-day operations of the crew including logistics, payroll, and travel.  Chris is a member of the NOAA Corps; he has both a BS in Marine Biology and an MS in Management Information Systems from Auburn University located in Auburn, Alabama.  He grew up in various places in the Midwest (his dad was in the U.S. Airforce) and has worked in several fields including information technology and zookeeping.  He applied to the NOAA Corps because he wanted to live and work near the ocean.
Chris, the Executive Officer of the Oscar Dyson

Chris, the Executive Officer of the Oscar Dyson

Something to Think About: 

In previous posts, we have explored invertebrates encountered on this mission. Today we will look at a group of vertebrates from the class  Osteichthyes, a word that comes from the Greek osteon meaning “bone” and ichthus meaning “fish.”  We will focus on some of the other fish besides pollock found in bottom trawls.  These bottom-dwellers are quite interesting creatures.

One of the most frequently found fish, other than pollock, is a type of rockfish called the Pacific Ocean Perch (POP); the species name is Sebastes alutus (Greek: Sebastes “August, venerable”, alutus “grow, nourish”).  This fish actually was seen in many trawls, both mid-water and bottom. As the picture below indicates, the body and fins of the POP are light red; however, there are dark olivaceous areas on back under soft dorsal fin and on the caudal peducle.  The maximum length of the fish is 55 cm and it is commonly found at a depth between 100-350 m.

Pacific Ocean Perch (a type of Rockfish)

Pacific Ocean Perch (a type of Rockfish)

A fish that belongs to the same genus as the POP is the Tiger Rockfish, Sebastes nigrocinctus ( Latin: niger, “black” and cinctus, “belt”).  We found this fish once in a bottom trawl.  The bottom of the tiger rockfish is light red to orange with several broad, vertical black-red bands on body.  It grows to a maximum length of 61 cm and is commonly found at a depth between 55 to 274 m.  Notice how similar it looks to the POP.

Tiger Rockfish, notice the similarities to the Pacific Ocean Perch

Tiger Rockfish, notice the similarities to the Pacific Ocean Perch

One of the most colorful fish that was found in a bottom trawl was the kelp greenling, Hexagrammos decagrammus (Greek:  hexa, “six”; grammus, “letter, signal”, deca, “ten”), a fish that generally hangs out in rocky reefs and kelp beds in relatively shallow waters (up to 46 m).  The fish is olive brown to bluish grey, speckled with irregular blue spots if male and reddish brown to gold spots if female (those we caught were most likely female).  The fish reach a maximum length of 53 cm.

Kelp Greenling

Kelp Greenling

Anne Mortimer: Swell Sleeping, July 12, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 12, 2011

Weather Data from the Bridge
Conditions: Foggy and windy, changing to partly sunny and windy
Air Temperature: 10.1 ⁰C
Sea Temperature: 7.6 ⁰C
Wind direction: 237 ⁰C
Wind speed: 20 knots
Wave height: 2-3 ft.
Swell height: 5-6 ft.

Science and Technology Log

Last night we had a “splitter” catch. The scientists found an area that they couldn’t pass up fishing, so at about 9pm the trawl was put in the water. The 540 ft. long Aleutian wing trawl brought in lots of pollock and Pacific ocean perch, a type of red-colored rockfish.  A catch is called a splitter when it is so big it won’t all fit on the table. To get a weight of the whole catch, the deck crew use a crane to weigh the net, then empty it out.  Then the catch is dumped into a bin that is split in two parts. Only one part of the bin is then raised, putting a sub-sample on the table to be worked-up. It took a long time to process all of the catch. We separated the species on a conveyor belt system, then the messy stuff happens. I mentioned that otoliths and stomachs are collected, but I don’t think I emphasized just how gross this can be. To sex the fish, we use a scalpel to slice the fish down the side, then look for larger pink-colored ovaries or a stringy, twisted looking testes. To collect otoliths, the fish skull is cut just behind the eyes and cracked open. The otoliths are then picked put with tweezers. If you are really good at pulling otoliths, you can pull both at once, which can be very challenging. My double-take record is only 2 in a row, but I’ve pulled both at once at least 5 times now!  The last messy thing is stomach collection. You can imagine what this entails, I’m sure. I’m happy to say that I’ve only had to hold the baggie for the stomach, not cut any out! Processing this catch took several hours– we didn’t end until after 1am.

red rockfish

This red-colored fish is a pacific ocean perch, or P.O.P. to a fish biologist.

Pacific ocean perch

When I am not processing a trawl or on the bridge observing, I have been working to annotate some videos from the cam-trawl. The cam-trawl is a stereo-camera system that takes snapshots of whatever comes through the net. This cam-trawl was designed by several of the scientists on the pollock survey. They are hoping it will help lead to less actual fish samples needed if the images can accurately provide evidence of species, numbers, and sizes. Some trawls would still have to be taken aboard for sexing, weights, and otolith and stomach samples.  Annotating the images basically means that I click through the images, counting each species of fish or invertebrate (usually jellies) that I see. This can very tedious, but the whole idea of the project is very exciting. I’ll talk more about the cam-trawl and this technology in my next blog.

Personal Log

Yesterday was my first real encounter with rocking and rolling on the Oscar Dyson. The winds were blowing at about 30 knots (that’s about 35 mph), and there was a lot of swell. Swell waves are long-wavelength surface waves that could have originated from a storm hundreds or thousands of miles away. The combination of these two made for a very rocky ride until we hid behind an island until sunrise. Since I go to bed at 4:30am, it wasn’t long before the boat was headed back out to unprotected waters, and I was rudely awakened by the swell. To say I didn’t have a swell sleep is an understatement. I had to take a nap this evening to compensate for my lost hours!

Jason Moeller: June 23-24, 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: Gulf of Alaska
Date: June 23-24, 2011

Ship Data
Latitude: 54.86 N
Longitude: -161.68 W
Wind: 12.1 knots
Surface Water Temperature: 8.5 degrees C
Air Temperature: 9.1 degrees C
Relative Humidity: 95%
Depth: 52.43 m

Personal Log

As I mentioned in the last post, everything here has settled into a routine from a personal standpoint, and on that end there is not much to write about. However, there were three things that broke up the monotony. First, as always, the scenery was beautiful.

Cove

Snow covered hills shield the cove from the winds. Look how smooth the ocean is!

cove2

The view off the back of the ship.

Second, I found out that even with all of the modern equipment on board, catching fish is still not guaranteed. We trawled three times last night on the 23rd and caught a total of 14 fish in all three trawls! Remember, a good sample size for one trawl is supposed to be 300 pollock, so this is the equivalent of fishing all day long and catching a minnow that just happened to swim into the fishing hook.

The first trawl caught absolutely nothing, as the fish dove underneath the net to escape the danger. The second trawl caught two pacific ocean perch and one pollock, and the third trawl caught eleven pollock. All in all, not the best fishing day.

pollock

The lone pollock from the second trawl.

Despite the poor fishing, we did bring up this neat little critter.

isopod

This is an isopod! These animals are very similar to the pillbugs (roly-polys) that we find in the US. Many marine isopods are parasites, and can be a danger to fish!

isopod2

This is the bottom view of an isopod

The third thing to break up the monotony was the Aleutian Islands earthquake. On the evening of June 23rd, a magnitude 7.2 earthquake shook the Aleutian Islands. According to ABC news, the earthquake was centered about 1,200 miles southwest of Anchorage. The quake spawned a brief tsunami warning that caused a large number of Dutch Harbor residents (Dutch Harbor is the home base of the show Deadliest Catch) to head for higher ground. We had been in the Aleutian Islands and Dutch Harbor area on our survey route, but had left two days before, so the Oscar Dysonwas completely unaffected by the earthquake.

Dutch Harbor residents seek higher ground after a tsunami warning was issued. AP photo by Jim Paulin.

Science and Technology Log

In order to obtain photos of all of this neat sealife, we first have to catch it! We catch fish by trawling for them. Some of you may not know exactly what I’m talking about, so let me explain. Trawling is a fishing method that pulls a long mesh net behind a boat in order to collect fish. Trawling is used to collect fish for both scientific purposes (like we’re doing) and also in commercial fishing operations. We have two types of fish trawls onboard the NOAA Ship Oscar Dyson — a mid-water trawl net and a bottom trawl net. We’ve used both types throughout our cruise, so let me tell you a little about each.

The mid-water trawl net is just as it sounds — it collects fish from the middle of the water column — not those that live on the seafloor, not those that live at the surface. The technical name for the net we have is an Aleutian Wing Trawl (AWT) — it’s commonly used by the commercial fishing industry.

trawl net

Part of the mid-water trawl net as it's being deployed.

The end of the net where the fish first enter has very large mesh, which is used to corral the fish and push them towards the bag at the end. The mesh gets progressively smaller and smaller the further into it you go, and at the very end (where the collecting bag is), the mesh size is 0.5 inches. The end (where the bag is, or where the fish are actually collected) is called the codend.

codend

One of the codends on the deck of the Oscar Dyson

This is the kind of net we use when we want to collect a pollock sample, because pollock are found in the water column, as opposed to right on the seafloor (in other words, pollock aren’t benthic animals). Our particular net is also modified a little from a “normal” AWT. Our trawl has three codends (collecting bags) on it, each of which can be opened and closed with a switch that is controlled onboard the ship. The mechanism that opens and closes each of the 3 codends is called the Multiple Opening and Closing Codend (MOCC) device. Using the MOCC gives us the ability to obtain 3 discrete samples of fish, which can then be processed in the fish lab.

MOCC

The MOCC apparatus, with the 3 nets extending off.

bar

The nets are opened and closed using a series of metal bars. (The bar here is the piece of metal running across the middle of the photo). The net has 6 of these bars. When the first bar is released, the first codend is ready to take in fish. When the second bar is dropped, the first codend is closed. The third and fourth bars open and close the second codend, and the fifth and sixth bars open and close the third codend.

trigger

This is the trigger mechanism for the codends on the MOCC. When the codend is released, the trigger mechanism is up. When the codend is locked and ready to go, it is in the down position.

One other modification we have on our mid-water trawl net is the attachment of a video camera to the net, so we can actually see the fish that are going into the codends.

camera

This is the camera apparatus hooked up to the trawl.

When we spot a school of fish on the acoustic displays, we then radio the bridge (where the captain is) and the deck (where the fishermen are) to let them know that we’d like to fish in a certain spot. The fishermen that are in charge of deploying the net can mechanically control how deep the net goes using hydraulic gears, and the depth that we fish at varies at each sampling location. Once the gear is deployed, it stays in the water for an amount of time determined by the amount of fish in the area, and then the fishermen begin to reel in the net. See the videos below to get an idea of how long the trawl nets are — they’re being reeled in the videos. Once all of the net (it’s VERY long — over 500 ft) is reeled back in, the fish in the codends are unloaded onto a big table on the deck using a crane. From there, the fish move into the lab and we begin processing them.

Videos of the net being reeled in and additional photos are below!

http://www.youtube.com/watch?v=I50Q4SJzzaE
http://www.youtube.com/watch?v=VVAqbAGcxRs

net end

This is the end of the trawl net. They are lines that basically hold onto the net.

codend

One of the codends before being opened up onto the conveyor belt. We are inside waiting for the fish to arrive.

open codend

Opening the codend to release the fish catch!

reeled in

The mid-water trawl net all reeled in!

The other type of trawl gear that we use is a bottom trawl, and again, it’s just as it sounds. The bottom trawl is outfitted with roller-type wheels that sort of roll and/or bounce over the seafloor. We use this trawl to collect benthic organisms like rockfish, Pacific ocean perch, and invertebrates. There’s usually a random pollock or cod in there, too. The biggest problem with bottom trawls is that the net can sometimes get snagged on rocks on the bottom, resulting in a hole being ripped in the net. Obviously, we try to avoid bottom trawling in rocky areas, but we can never be 100% sure that there aren’t any rogue rocks sitting on the bottom 🙂

bottom trawl

The mesh and wheels of the bottom trawl.

btrawl2

More of the bottom trawl

btrawlreel

The bottom trawl, all reeled in!

Species Seen

Northern Fulmar
Gulls
Pollock
Pacific Ocean Perch (aka rockfish)
coral
Isopod

Reader Question(s) of the Day!

The first question for today comes from Rich, Wanda, and Ryan Ellis! Ryan is in the homeschool Tuesday class at the Zoo.

Q. We looked up what an anemone was and we found it was some kind of plant. Is that correct?

A. Great question! The answer is both yes and no. There is a type of flowering plant called the anemone. There are about 120 different species, and they are in the buttercup family. For one example of the plant, look below!

Anemone Nemorosa

Anemone Nemorosa. Taken from pacificbulbsociety.org

The sea anemone, however, is not actually a plant but an animal! Anemones are classified as cnidarians, which are animals that have specialized cells for capturing prey! In anemones, these are called nematocysts, which have toxin and a harpoon like structure to deliver the toxin. When the nematocysts are touched, the harpoon structure injects the toxin into the animal that touches it.

Cnidarians also have bodies consist of mesoglea, a non living jelly like substance. They generally have a mouth that is surrounded by the tentacles mentioned above.

Anemone

The Anemone we found.

The second question comes from my wife Olivia.

Q. What has surprised you most about this trip? Any unexpected or odd situations?

A. I think the thing that has surprised me the most is the amount of down time I have had. When I came on, I assumed that it would be physical and intense, like the show Deadliest Catch, where I would spend my whole time fishing and then working on the science. I figured that I would be absolutely toast by the end of my shift.

While I have worked hard and learned a lot, I have quite a bit of down time. Processing a catch takes about one hour, and we fish on average once or twice a night. That means I am processing fish for roughly two hours at most, and my shift is twelve hours. I have gotten a fair amount of extra work done, as well as a lot of pleasure reading and movie watching.

As for unexpected and odd situations, I didn’t really expect to get your camera killed by a wave. Fortunately, I have been allowed to use the scientist camera, and have been able to scavenge photos from other cameras, so I will still have plenty of pictures.

Another technological oddball that I didn’t think about beforehand was that certain headings (mainly if we are going north) will cut off the internet, which is normally fantastic. It is frustrating to have a photo 90% downloaded only to have the ship change vectors, head north, and cut off the download, forcing me to redownload the whole photo.
I also didn’t expect that the fish would be able to dodge the trawl net as effectively as they have. We have had four or five “misses” so far because the fish will not stay in one spot and let us catch them. While the use of sonar and acoustics has greatly improved our ability to catch fish, catching fish is by no means assured.

Perhaps the biggest “Are you kidding me?” moment though, comes from James and David Segrest asking me about sharks (June 17-18 post). An hour after I read the question, we trawled for the first time of the trip, and naturally the first thing we caught was the sleeper shark. Also naturally, I haven’t seen a shark since. Sometimes, you just get lucky.