Lesley Urasky: Smile and say, “Squid!”, June 20, 2012

 NOAA Teacher at Sea
Lesley Urasky
Aboard the NOAA ship Pisces
June 16 – June 29, 2012

 Mission:  SEAMAP Caribbean Reef Fish Survey
Geographical area of cruise: St. Croix, U.S. Virgin Islands
Date: June 20, 2012

Location:
Latitude: 18.1937
Longitude: -64.7737

Weather Data from the Bridge:

Air Temperature: 28°C (83°F)
Wind Speed:  19 knots (22 mph), Beaufort scale: 5
Wind Direction: from N
Relative Humidity: 80%
Barometric Pressure: 1,014.90  mb
Surface Water Temperature: 28°C (83°F)

Science and Technology Log

The cameras are a very important aspect of the abundance survey the cruise is conducting.  Since catching fish is an iffy prospect (you may catch some, you may not) the cameras are extremely important in determining the abundance and variety of reef fish.  At every site sampled during daylight hours, we deploy the camera array.  The cameras can only be utilized during the daytime because there are no lights – video relies on the ambient light filtering down from the surface.

Camera array – the lens of one of the cameras is facing forward.

Deployment of the array at a site begins once the Bridge verifies we are over the sampling site. The camera array is turned on and is raised over the rail of the ship and lowered to the water’s surface on a line from a winch that has a ‘quick release’ attached to the array.  Once over the surface, a deck hand pulls on the line to the quick release allowing the array to free fall to the bottom of the ocean. Attached to the array is enough line with buoys attached. The buoys mark the array at the surface and give the deck hands something to aim for with the grappling hook when it is time for the array to be retrieved.  Once the buoys are on deck, a hydraulic pot hauler is used to raise the array from the sea floor to the side of the ship.  From there,  another winch is used to bring the array on board.

Vic, Jordan, Joey, and Joe deploying the camera array.

When the array is deployed, a scientist starts a computer program that collects the time, position and depth the array was dropped at. The array is allowed to “soak” on the bottom for about 38 minutes. The initial 3-5 minutes are for the cameras to power up and allow any sediment or debris on the bottom to settle after the array displaces it. The cameras are only actually recording for 25 of those minutes. The final 3-5 minutes are when the computers are powering down.  At one point in time, the cameras on the array were actual video cameras sealed in waterproof, seawater-rated cases. With this system, after each deployment, every individual case had to be physically removed from the array, opened up, and the DV tape switched out.  With the new system, there are a series of four digital cameras that communicate wirelessly with the computers inside the dry lab.

We did have a short-lived problem with one of the digital cameras — it quit working and the electronics technician that takes care of the cameras, Kenny Wilkinson, took a couple of nights to trouble shoot and repair it.  During this time period, we reverted back to the original standard video camera.  Throughout the cruise, Kenny uploads the videos taken during the day and repairs the cameras at night so they will be ready for the next day’s deployments.

Squid (before being cut into pieces) used for bait on the camera array

Besides the structure of the camera array which is designed to attract reef fish, the array is baited with squid.  A bag of frozen, cut squid hangs down near the middle.  The squid is replaced at every site.

Adding bait to the camera array.

In addition to the bait bag, a Temperature Depth  Recorder (TDR) is attached near the center, hanging downward near the bottom third of the array. The purpose of the TDR is to measure the temperature of the water at various depths.  It is also used to verify that the depth where the camera comes to rest on the ocean bottom and is roughly equivalent to what the acoustic sounding reports at the site.  This is important because the camera generally doesn’t settle directly beneath the ship.  Its location is ultimately determined by the drift as it falls through the water column and current.  The actual TDR instrument is very small and is attached to the array near the bait bag.  After retrieving the array at each site, the TDR is removed from the array and brought inside to download the information.  To download, there is a small magnet that is used to tap the instrument (once) and then a stylus attached to the computer is used to read a flash of light emitted by an LED.  The magnet is then tapped four times on the instrument to clear the previous run’s data.  The data actually records the pressure exerted by the overlying water column in pounds per square inch (psi) which is then converted to a depth.

TDR instrument

Computer screen showing the data downloaded from the TDR.

The video from each day is uploaded to the computer system during the night shift.  The following day, Kevin Rademacher (chief scientist), views the videos and quickly annotates the “highlights”.  The following things are noted:  visual clarity (turbidity [cloudiness due to suspended materials], what the lighting is like [backlit], and possible focusing issues), substrate (what the bottom is made of), commercially viable fish, fish with specific management plans, presence of lionfish (an invasive species), and fish behavior.  Of the four cameras, the one with the best available image is noted for later viewing.

Computer data entry form for camera array image logs

Once back at the lab, the videos are more completely analyzed.  A typical 20-minute video will take anywhere from 30 minutes to three days to complete. This is highly dependent upon density and diversity of fish species seen; the greater the density and diversity, the longer or more viewing events it will take.  The experience of the reader is also an important factor. Depending upon the level of expertise, a review system is in place to “back read” or verify species identification. The resulting data is entered into a database which is then used to assign yearly data points for trend analysis. The final database is submitted to the various management councils.  From there, management or fisheries rebuilding plans are developed and hopefully, implemented.

Spotted moray eel viewed from the camera array.  He’s well camouflaged; can you find him?

Coney with a parasitic isopod attached below its eye.

Two Lionfish – an invasive species

Personal Log

Today, we are off the coast of St. Thomas and St. John in the U.S. Virgin Islands.  We traveled from the southern coast of  St. Croix, went around the western tip of the island and across the straight.  When I woke up I could see not only St. Thomas and St. John, but a host of smaller islands located off their coastline.

Map of the Virgin Islands. St. Croix and St. Thomas are separated by 35 miles of ocean. It took us about 3 hours to cross to our next set of sampling sites.

Around dinner time last night we had an interesting event happen on board.  They announced over the radio system that there was a leak in the water line and asked  us not to use the heads (toilets).  A while later, they announced no unnecessary use of water (showers, etc.); following that they shut off all water.  It didn’t take long for the repairs to occur, and soon the water was returned.  However, when I went to dinner, I discovered that the stateroom I’m sharing with Kelly Schill, the Ops Officer, had flooded.  Fortunately, the effects of the flooding were not nearly as bad as I had feared.  Only a small portion of the room had been affected.  The crew did a great job of rapidly assessing the problem and fixing it in a timely manner.  After this, I have absolutely no fear about any problems on board because I know the crew will react swiftly, maintain safety, and be professional all the while.

Last night was the first sunset I’ve seen since I’ve been on board.  Up until this point, it has been too hazy and cloudy.  The current haze is caused by dust/sand storms in the Sahara Desert blowing minute particles across the Atlantic Ocean.

St. Thomas sunset

Today has been a slow day with almost nary a fish caught.  We did catch one fish, but by default.  It was near the surface and hooked onto our bait.  We immediately reeled in the line and extracted it.  It was necessary to remove it because it would have skewed our data since it was caught at the surface and not near the reef.  This fish was a really exciting one for me to see, because it was a Shark Sucker (Echeneis naucrates).  These are the fish you may have seen that hang on to sharks waiting for tasty tidbits to float by.  They are always on the lookout for a free meal.

Shark sucker on measuring board

One of the most interesting aspects of the shark sucker is that they have a suction device called laminae on top of their heads that looks a little like a grooved Venetian blind system.  In order to attach to the shark (or other organism), they “open the blinds” and then close them creating a suction-like connection.

The “sucker” structure on the Shark Sucker. Don’t they look like Venetian blinds?

I got to not only see and feel this structure on the fish, but also let it attach itself to my arm!  It was the neatest feeling ever! The laminae are actually a modified dorsal spines; these spines are needed because of the roughness of shark’s skin. When the shark sucker detached itself from me, it left a red, slightly irritated mark on my arm that disappeared after a couple of hours.

Look, Ma, No Hands! Shark sucker attached to my arm.

Tomorrow we’ll be helping place a buoy in between St. Croix and St. Thomas.  It will be interesting to see the process and how the anchor is attached.

With all the weird and wonderful animals we’re retrieving, I can’t wait to see what another day of fishing brings.

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.