NOAA Teacher at Sea: Tammy Orilio NOAA Ship Oscar Dyson Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 25 June 2011
Weather Data from the Bridge:
Latitude: 54.91
Longitude: -161.27
Wind Speed: 13.80 knots
Surface Water Temp: 7.9 degrees C
Water Depth: 113.78 m
Air Temp: 8.3 degrees C
Relative Humidity: 97%
Personal Log:
Unfortunately, it’s been another day of no fishing for me 🙁 My shift just ended, and we’ve only seen small, scattered groups of fish on the acoustic displays today- not enough to put the nets into the water. Yesterday was nearly the same as today, but we did do a plankton trawl to sample the krill in the water. I’ll write more about that in another post.
From what I’ve heard from other Teachers at Sea, I expected to be working in the fish lab pretty much the entire duration of my 12 hour shift. Unfortunately, this hasn’t been the case! But, there’s not much I can do if there are only a scattering of fish in an area. Even the scientists are saying that they’re surprised by the lack of fish on this leg of the survey. I still have another 5 days or so (depending on when we start heading back to port, and if we’re working on the way there, or just straight sailing), so hopefully I’ll see some more action over the last few days of the trip. However, I know that we can’t control whether the fish are here or not- it’s all part of the science process!
The science team will be disembarking on Thursday June 30 and heading home, but the trip is definitely not over for the rest of the crew and NOAA officers. Another group of scientists and two more Teachers at Sea will be boarding the ship, and then they’ll set sail for another 3 weeks, doing the same thing we’ve been doing, just in a different part of the Gulf of Alaska. Then, the original group of scientists (that are on board now) and two more teachers will come back for the last leg of the trip. This method of switching people every few weeks is advantageous so that no one gets too run down or antsy to get off the ship. However, most of the deck crew, engineers, and NOAA officers stay onboard for all 3 legs of the trip- I don’t know if I could do that! I’ve been on board for 2 weeks now, and I’m doing fine, but I couldn’t imagine being on here for 9 or 10 weeks!
Lastly, here are a few photos of the area we’ve been in the last two days. Looking at our digital map, we’ve got nothing to look at but open water for the next 10 hours or so, but we’re moving into an area filled with lots of little islands in the next day, so I’m sure I’ll get some photos!
I can see Russia from my house!! (kidding, of course)
NOAA Teacher at Sea: Tammy Orilio NOAA Ship Oscar Dyson Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 24 June 2011
Weather Data from the Bridge:
Latitude: 54.14 N
Longitude: -164.16
Wind Speed: 9.73 knots
Surface Water Temp: 7.0 degrees C
Water Depth: 92.75 m
Air Temp: 7.2 degrees C
Relative Humidity: 101%
Science & Technology Log:
I’ve been talking a lot about trawling for fish, and I realize that 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. 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. 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’tbenthic 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. 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.
The MOCC apparatus, with the 3 nets extending off.Part of the mid-water trawl net as it’s being deployed.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 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.
The end of the trawl net. These are the lines that basically hold on to the net!The mid-water trawl net all reeled in.One of the codends before being opened up.
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. As I mentioned in my last post (“Today’s Catch”), 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 🙂
The mesh and the wheels of the bottom trawl.More of the bottom trawl.The bottom trawl all reeled in.
Personal Log:
It’s been a quiet couple of days. On Wednesday, we didn’t see any fish until late in my shift, then we did a mid-water trawl. We ended up actually busting the bag- that’s how many fish we ended up collecting!! Once the codends were opened, we immediately began processing- first separating the pollock from everything else we caught. After sorting, I got to work on sexing the fish- it’s a kind of gruesome job, because you have to take a scalpel and cut them open (while they’re still alive!), exposing their innards- definitely NOT like the preserved organisms we dissect in class. I’m not a huge fan of cutting them open, so I moved on to measuring the length of the male fish- there were so many males in our catch, I was the last one working! After I cleaned up, that was the end of my shift. We were near some islands at the end of my shift, and the bridge called down to the lab to tell us that there some whales off the starboard side of the ship. I grabbed my camera and ran up to the deck, scanning the water for whales. Finally, I spotted a pod waaaay off the starboard side- they were too far off to get a good picture, and I couldn’t even tell what kind they were, but I was able to see them spouting water out of their blowholes, and it looked like one of them breached. The officers up on the bridge said they thought they were minke whales.
Thursday we didn’t see any fish (well, not enough to put our gear in the water) all day, so no fishing for me. Right now, it’s about 9:30 a.m. on Friday, and we’re just cruising to begin our next set of transects. I just read that there was an earthquake in the western Aleutian Islands last night- magnitude 7.2! Holy moly, I was just there! Apparently, people felt the earthquake as far east as Dutch Harbor on the island of Unalaska, and they had a tsunami warning go off. It’s crazy to think that I was in that area a couple days ago!
Question of the Day:
Speaking of tsunamis…What would cause the East Coast of the U.S. to be hit by a megatsunami?
NOAA Teacher at Sea: Tammy Orilio NOAA Ship Oscar Dyson Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 21 June 2011
Weather Data from the Bridge:
Latitude: 54.25 N
Longitude: -163.31 W
Wind Speed: 13.56 knots
Surface Water Temp: 7.5 degrees C
Water Depth: 69.38 m
Air Temp: 6.8 degrees C
Relative Humidity: 95%
Personal Log:
We did our (well, my) first bottom trawl today. The trawl net is outfitted with rollers/wheels that ride over the seafloor while the net collects benthic (bottom-dwelling) organisms. One thing I talk about in Marine 2 is how bottom trawling is damaging to the environment, and we definitely saw that firsthand today- there were quite a few rocks brought up in the net along with the animals. The seafloor was not as flat as we had hoped- in fact, the net ended up with a 4-foot hole ripped in it, which the deckhands/lead fishermen sewed for us later on in the day. Now, in the case of bottom trawling to collect scientific data, I don’t have a problem…but in the case of doing it for profit, as in the case of commercial fishing operations, I can’t abide by that. I would probably feel a little different if ALL we were doing was bottom trawls, but we’ve only done 2 so far, so…that’s how I’m rationalizing it. What’s your take on this? Should scientists damage an environment and/or kill organisms just to collect scientific data? And just so you know, the data we’re collecting on this survey is not just sitting around, completely useless- we are using it to actually help manage fish populations and regulate commercial fishing. The limits that all commercial fishermen have- how much they can legally take- are determined by knowing the current population status, and we can only learn that by seeing what’s out there, where things are, their age, what they’ve been eating, etc etc.
Following are some pictures of the animals from today’s bottom trawl.
Black Rockfish- we had some fried rockfish for dinner tonight!Cushion star- also called Slime Star b/c it secretes slime when it’s disturbed…which I discovered today!Fanellia compressa- a soft coral- it’s pinkish/peachish in colorAtka mackerel
One last thing…we went by Unimak Island today- it’s the easternmost of the Aleutians, which means that we will soon be re-entering the Alaskan peninsula- but we’re still a long way from Kodiak 🙂 Unimak Island has an active volcano on it called Shishaldin, and we were able to see it today. Pretty awesome!
Science & Technology Log: walleye pollock, which is an important fish species here in Alaska. Walleye pollock make up 56.3% of the groundfish catch in Alaska (http://www.afsc.noaa.gov/species/pollock.php), and chances are you’ve eaten it before. It’s a commonly used fish in all of the fast food restaurants, in fish sticks, and it’s also used to make imitation crab meat.
Our first catch had a little over 300 walleye pollock, and we processed all of them. Three hundred is an ideal sample size for this species. If, for example, we had caught 2,000 pollock, we would only have processed 300 of the fish, and we would have released the rest of them back into the ocean. Check out the photos/captions below to see how we process the catch.
After sexing, we then measured the length of each fish. There’s a ruler embedded in the lab table, and we laid each fish down on the ruler. Then we put a hand-held sensor at the caudal (tail) fin of the fish, and the total length was recorded on a computer.At the sexing station, cutting open pollack.
We also removed and preserved 20 stomachs from randomly selected fish in order to (later) analyze what they had been eating prior to them being caught. One of the last things we do is collect otoliths from each of those 20 fish. Otoliths are ear bones, and they are used to determine the age of a fish- they have rings, similar to what you see in trees.
Here’s a look at some of the bycatch in our nets:
Basket Star. Marine 1: What phylum are sea stars in?Arrowtooth flounder.The reason(s) WHY they’re called ARROWTOOTH flounder.
Animals Spotted:
walleye pollock
chum salmon
rockfish
arrowtooth flounder
squid
basket star
Northern Fulmars
Gulls
Albatross (couldn’t tell what kind)
* I did spot some kind of pinniped yesterday, but have no idea what exactly it was!
Personal Log:
I was very excited that we finally got to fish today!! As an added bonus, we caught 2 salmon in the trawl, which means we’re having salmon for dinner tonight! We we supposed the have teriyaki steak, but the cook has changed it to teriyaki salmon instead 🙂 I didn’t get any pics of them because my gloves were covered in fish scales, blood, and guts by that point and I didn’t want to get any of that funk on my camera 🙂
We passed by Dutch Harbor yesterday- it should sound familiar if you watch Deadliest Catch. We didn’t go into the Harbor, so no, I didn’t see any of the crab boats or any of the guys from the show! Below are some pics of the Aleutian Islands that I’ve see thus far…many more to come, since we still have another 13 days (give or take) of sailing left!
QUESTION(S) OF THE DAY:
The Aleutian Islands were formed at the boundary where the North American and Pacific Plates are coming together. The Pacific Plate is denser than the North American Plate, so it slides underneath the North American Plate. What is this type of plate boundary called (where plates move towards each other), and what is it called when one plate slides underneath another?
One thing we’re doing on this trip is trawling for fish. We are conducting both mid-water and bottom trawls. Describe one advantage and one disadvantage to trawling in order to gather scientific data.
Weather Data from the Bridge:
Latitude: 52.34 N
Longitude: -167.51 W
Wind Speed: 7.25 knots
Surface Water Temp: 6.6 degrees C (~43.9 degrees F)
Water Depth: 63.53 m
Air Temp: 7.1 degrees C (~44.8 degrees F)
Relative Humidity: 101% (it’s very cloudy/foggy, but not raining)
Science & Technology Log:
The XBT Launcher mechanism.
Today I used the Expendable Bathythermograph (XBT) a few times. The WHAT?? The expendable part means we use it once and don’t recover it. Let’s break down the second part into the two main roots: bathy– which refers to depth, and thermo–which refers to temperature. This probe measures the temperature and depth of the water when it is dropped over the starboard (right) side of the ship.
“Dropping” isn’t exactly the correct phrase- we use a launcher that kind of resembles a gun. The probe sits inside of the black tube, and after we uncap the end of the tube, we basically fling our arm out over the side of the ship to launch the probe into the water. I can’t show you any pics of the probe, because if we take it out of the black tube, it’ll start recording data. The probe is connected to a length of copper wire, which runs continuously as the probe falls through the water column, collecting data. It’s important to launch the probe as far away from the ship as possible, because if the copper wire touches the metal on the ship, the data feed will be disrupted and we’d have to launch another probe. Big waste of money and equipment! One of the survey technicians decides to cut the wire (or tells me to) when they’ve decided that a sufficient amount of data has been collected, and we can then look at a graph to see the relationship between temperature and depth.
The XBT is a quick and easy method of data collection, and can be run while the ship is in motion. The ship does have another piece of equipment- the Conductivity, Temperature, and Depth meter (CTD)- to collect the same data, but the CTD is very big and bulky, and the ship must be stopped in order to deploy the CTD. The CTD can also measure parameters such as dissolved oxygen concentration, current velocity, and other things (depending on the additional equipment on the meter). The main advantage the XBT has is that it is quick and can be deployed as the ship is sailing.
Data Collected from an XBT probe today:
Latitude: 53.20 N
Longitude: -167.46 W
Water Temp at Surface: 6.7 degrees C
Water Temp at Bottom: 5.1 degrees C
Thermocline located from 0-25 meters depth
What is a thermocline, you ask? Root word time! We’ve already gone over thermo, and cline refers to a gradient, or where things change rapidly. So, the thermocline is the area where you see the greatest change in temperature. See the diagram as an example (it’s not our actual data). Beneath the thermocline, the water temperature remains relatively constant. Personal log:
Launching the XBT in full safety gear (minus the hardhat, it fell off)Safety first, my friends.
Yesterday, as we were finally on our first transect of many, we needed to use the XBT to collect temperature and depth data. A couple of the scientists told me that I could do it- yay, something for me to do!! So I go to the lab room and see a ton of safety gear out- heavy coat, hardhat, gloves, soundproof earmuffs, goggles. The survey tech tells me that I have to use all that protective gear because the XBT launcher is just like a gun- have I shot a gun before? No! So this is interesting. I don the gear, and he explains what I need to do…which doesn’t seem that dangerous. So now here I am, all geared up, and the rest of the scientists come trickling in to the lab to watch me. That should’ve been a red light right there. Why would they want to watch me do something so simple? Turns out that it’s something that all the new people on the boat go through- we get all hyped up about shooting a loud gun, get loaded with gear, and then…not much. So I basically got all dressed up in my protective gear for no other reason than the entertainment of the crew!!
QUESTION OF THE DAY:
Why is it important to know the temperature and/or depth of the water that we’re trawling in?
