This blog will describe my time as a participant in NOAA's Teacher at Sea Program. I'm sailing on the NOAA Ship Oscar Dyson in the Gulf of Alaska for three weeks in June. We will be collecting acoustic and trawl data to determine the population status of walleye pollack and other fish species in the Gulf of Alaska.
If you have any questions, feel free to email me at tammyorilio@gmail.com
Science & Technology Log:
What are krill, you ask? They're animals in the Phylum Arthropoda, which means they're related to insects, spiders, crabs, lobsters, etc. They have jointed legs and an exoskeleton, are usually a couple centimeters in length, and are reddish/orange-ish in color. They can often be found in dense schools near the surface of the water, and play an important role in the ecosystem as a source of food for lots of larger animals (like fish, whales, & penguins).
I've mentioned the two types of trawl gear that we use to catch fish, but if we want to catch smaller things like plankton, the mesh on those nets is way too small. Therefore, we use a third type of trawl called the Methot which has very fine mesh to corral the plankton down into a collection container at the end of the net. In addition to having a hard container at the end- as opposed to just a bag/codend that you see in the fish trawls- the Methot trawl also has a large metal frame at the beginning of the net. Check out the photos below.
The Methot trawl being taken out of the water. Note the square frame.
The container that collects all of the plankton in the net.
After the net is brought back on deck, one of the fishermen or deckhands brings the container of krill into the fish lab. The first thing we do is dump the container into a sieve or a bucket and start picking out everything that isn't krill. The two most common things that are collected (besides krill) are gelatinous animals (like jellyfish & salps) and larval fish. The fish get weighed (as one big unit, not individually) and then frozen for someone to look at later on.
The larval fish that we separated from one plankton tow.
After sorting the catch, we're left with a big pile of krill, which gets weighed. We then take a small subsample from the big pile of krill (it's a totally random amount- depends on how much we scoop out!) and then weigh the subsample. Then the fun begins, as I'm the one that does this job- I get to count every single individual krill in the subsample. Tedious work. All of the data is then entered into the computer system, and the krill and anything else that we've caught (besides the larval fish) are thrown back into the water.
Sorting through the big pile of krill.
How many individual krill are in this picture? You get a prize if you're the closest without going over :)
Personal Log:
I mentioned that once we're done with the krill, we throw it back into the water- that was until I came aboard! My eel (Ms. Oreelio for those of you that don't know!) eats dried krill, and I'm going to run out soon, so I figured I'd take these krill home with me! I got a gallon-size baggie from the galley (kitchen) and filled it up with krill, and holy cow, it's a lot!! I stuck it in our freezer- which is at -22 degrees C (or 7.6 degrees F) so now I have a big frozen block of krill to take back home with me. What a great souvenir.
Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska
Date: 28 June 2011
Weather Data from the Bridge:
Latitude: 57.11 N
Longitude: -155.58 W
Wind Speed: 3.61 knots
Surface Water Temp: 9.0 degrees C
Water Depth: 271.10 m
Air Temp: 8.3 degrees C
Relative Humidity: 84%
Science & Technology Log:
Today we will look at the acoustic system of the NOAA Ship Oscar Dyson! Acoustics is the science that studies how waves (including vibrations & sound waves) move through solids, liquids, and gases. The Oscar Dyson uses an acoustic system to find the pollock that we process.
The process begins when a piece of equipment called a transducer converts an electrical pulse into a sound wave. The transducers are located on the underside of the ship (in the water). The sound travels away from the vessel at roughly1500 feet per minute, and continues to do so until the sound wave hits another object such as a bubble, plankton, a fish, or the bottom. When the sound wave hits an object, it reflects the sound wave, sending the sound wave back to the Oscar Dyson as an echo. Equipment onboard listens to the echo.
The computers look at two critical pieces of information from the returning sound wave. First, it measures the time that it took the echo to travel back to the ship. This piece of information gives the scientists onboard the distance the sound wave traveled. Remember that sound travels at roughly 1500 feet per minute. If the sound came back in one minute, then the object that the sound wave hit is 750 feet away (the sound traveled 750 feet to the object, hit the object, and then traveled 750 feet back to the boat).
The second critical piece of information is the intensity of the echo. The intensity of the echo tells the scientists how small or how large an object is, and this gives us an idea of what the sound wave hit. Tiny echos near the surface are almost certainly plankton, but larger objects in the midwater might be a school of fish.
An image of the computer screen that shows a great number of fish. This was taken underneath the boat as we were line fishing in Sand Point.
The same spot as above, but with practically no fish.
An image of the screen during a trawl. You can actually see the net, it is the two brown lines that are running from left to right towards the top of the screen.
One of the things that surprised me the most was that fish and bubbles often look similar enough under water that it can fool the acoustics team into thinking that the bubbles are actually fish. This is because many species of fish have gas pockets inside of them, and so the readout looks very similar. The gas pockets are technically called “swim bladders” and they are used to help the fish control buoyancy in the water.
Personal Log:
Well, it's now Tuesday morning, and we are making excellent time on our way back to Kodiak. The water has not been as rough as expected, thank goodness! Yesterday's forecast said we'd encounter winds up to 35 knots and seas up to 18 feet, but I have definitely not felt anything like that. It's not quite over yet, though, so I'm not getting my hopes up too much.
We're scheduled to arrive in Kodiak sometime tomorrow (I don't know the approximate time yet), or maybe even later tonight, which means I'll have a day to kill there. I'm looking forward to it because I didn't get a chance to explore when I first arrived. When I made it to Kodiak, I only had the clothes on my back, and it was raining for nearly the entire two days I was there, so I didn't want to go outside and explore because if my clothes got wet, I had nothing else to change into! One animal I haven't seen on this trip is an eagle, and I hear they're very easy to spot in Kodiak, so hopefully I'll get a chance to look around tomorrow!
Question of the Day:
What is one way that bony fishes can control the amount of gas in their swim bladder?
Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska
Date: 27 June 2011
Weather Data from the Bridge:
Latitude: 55.33 N
Longitude: -160.52 W
Wind Speed: 18.24 knots
Surface Water Temp: 7.3 degrees C
Water Depth: 28.43 m
Air Temp: 8.2 degrees C
Relative Humidity: 91%
Personal Log:
I woke up yesterday to the sound of the anchor being dropped (it's a really loud noise that goes on for a few minutes). We weren't scheduled to stop anywhere, so I figured something out of the ordinary had to be happening in order for us to be dropping anchor, and I soon found out what happened. Turns out a crew member had an accident onboard, so we headed to the nearest community to get to a medical facility, which is Sand Point- a small little fishing village.
So we ended up spending the day anchored in Sand Point yesterday. It was foggy & rainy yet again, so a few of the scientists purchased fishing licenses online and they fished off the back deck. They ended up catching some cod, halibut, and sculpins (Irish lords to be exact). They also ended up dragging some kelp up to the surface, and of course I was excited about that because I love seaweeds :) And I've never seen live kelp in person before- I've only seen the dried stuff we ate in Marine 1!
Some buildings and a couple of windmills in Sand Point.
A barge anchored in the bay.
Morning on 26 June 2011.
A helicopter leaves the airport on 27 June. That spit of land is the runway.
Docks.
We think this is Laminaria, but not positive.
Some kind of kelp. Salty.
We are still anchored here, because one of our science team members is going to fly out of here this afternoon to get to a meeting in Juneau. Sadly, our trip is essentially over- we are not going to do any more fishing :( I'm disappointed that the trip was cut a few days short, but the situation was out of everyone's control, so there's nothing I can do about it. I am thankful that I did get to go on this trip even if it was short- it was a great experience!
We're supposed to be leaving Sand Point at some point this evening, and the weather forecast doesn't look so good. High winds- up to 35 knots (that's about 40 mph) and 18 ft seas are forecast for tonight, with only a little decrease for tomorrow. Going to be a great time!! I will definitely have to take my seasick medication before we leave here.
Question of the Day:
What kingdom & phylum are brown algae (such as kelp) in?
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)
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.
Opening the codend to release the fish catch.
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?
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 color
Atka 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: We finally started fishing! The objective of this survey is to determine the population status of 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.
Fish are first moved onto the conveyor belt, where we separate the pollock from bycatch in the net.
After separating the pollock, the next step is to sex them. We make a crescent-shaped slice in their ventral side to expose their gonads. Each sex then goes into a separate container for the next step.
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.
