NOAA Teacher at Sea
Staci DeSchryver
Onboard NOAA Ship Oscar Dyson
July 26 – August 12, 2011
Mission: Pollock Survey
Geographical Area: Gulf of Alaska
Location: Kodiak, AK
Heading: back to the docks
Date: August 12, 2011
Weather Data From the Bridge: N/A
Science and Technology Log
My last night on the Oscar Dyson was a busy one! Because our trip was cut so short, we had to “break protocol” so to speak. Typically, nighttime operations consist of seafloor mapping (which I will get to in a minute), and do not consist of trawling for Pollock. For science students, you probably have a good idea why – running operations only in the daytime means that the experiment is controlled. Since Pollock behave differently in the night-time, it is important to only run operations when their behavior is consistent. However, because we were so short on time, we had to make a “run” for the shelf break that got us to the area well after dark. So we got to do one more trawl! This one was the best kind, in my humble opinion. We completed a bottom trawl, which means that the net went almost down to the bottom of the ocean – within a couple of meters. The reason why bottom trawls are so neat is because there are plenty of ocean critters down there that the average Joe doesn’t get to see on a daily basis. Of course, the scientists do their absolute best to catch only Pollock to minimize bycatch, but one or two fish of different species are difficult to avoid. On this trawl, we had a few jellies, two Pacific Ocean Perch, and a Herring. We finished late – right around one in the morning. At that time, we began our night-time operations.
Night time operations are run by Dr. Jodi Pirtle. Dr. Pirtle is a Post-Doctoral Research Associate at the University of New Hampshire Center for Coastal and Ocean Mapping. Her research is a collaborative effort between the UNH CCOM and the NOAA Alaska Fisheries Science Center. Even though Jodi is traveling all the way from New Hampshire, she is actually very close to home right now. She is quite connected to the Alaska fisheries – she grew up in Alaska, and has both family and friends who are involved in the commercial fishing industry. The fisheries hold a place very close to her heart, and her passion for her current line of work is well evident.
So, why, then, does Dr. Pirtle work in the cover of night?
At first I suspected it was some sort of secret service operation, but the reality is much more strange and explainable. Her line of work is a side project on the Oscar Dyson, which means that she can work when the ship is not working for its primary purposes. Hence, she works from 6pm until 6am. One focus of her research is to identify whether or not certain areas of the Gulf of Alaska are trawlable or untrawlable by the Alaska Fisheries Science Center bottom-trawl survey for groundfish. How is an area determined to be untrawlable? Let’s say, for example, there is a commercial fishing ship somewhere in the Gulf of Alaska. This ship decides to do a similar trawl as the one that I did earlier this evening, but they use a net that makes contact with the seafloor because they are fishing for groundfish species – say, Rockfish, for example. But, something happens. When the net comes up, it is all torn up – as though it got caught on a series of rocks or ledges. In order to warn other ships of the dangers of losing a very expensive net, the fisherman deems the area “untrawlable.” It’s kind of like putting caution tape around the area.
Untrawlable areas are problematic for scientists because every area deemed untrawlable is an area where they can’t sample with the bottom-trawl gear. For example, a large component of the groundfish fishery are several species of rockfish (Sebastes spp.) that associate with a rocky habitat. Rockfish are delicious with garlic and butter, but they are sneaky little guys because they like hanging out around rocks (who knew?). Many rockfish could be in areas that are untrawlable, but scientists would never know because it is inadvisable to tow a bottom-trawl net in the area to find out. In a sense, untrawlable areas are a source of error, or uncertainty in the population estimate for species of groundfish in those areas. This is where Dr. Pirtle’s research starts.
A few years ago, a group did research in an area called Snakehead Bank – a location previously deemed to be untrawlable. They wanted to tighten the definition of “untrawlable.” For example, there is a possibility that an untrawlable area is covered with steep cliffs, many sharp, large rocks, and impossibly tough relief. However, there is also the possiblity that the area is relatively flat and trawlable, but the fisherman was just unlucky enough to drag his or her net over a rogue boulder that found its way onto the vast, flat, continental shelf. So, the scientists decided to see what kind of “untrawlable” this particular area was. The group took the time to make a bathymetric profile of the area and couple that research with camera drops – video cameras that would make the trek to the bottom of the ocean and provide a second set of data for scientists to confirm what the bathymetric profile showed them. From the camera drops and the bathymetry, the scientists determined that Snakehead bank was not completely untrawlable – in fact, most areas could support trawl nets without the risk of tearing the nets. Dr. Pirtle is continuing with this important work.
One focus of the research is determining seafloor trawlability in the Gulf of Alaska using the same acoustic transducers that we use to catch fish in our daytime operations. The fishery that the survey is concerned about is groundfish – a general term that encompasses many species such as flatfish, cod, and rockfish. These sneaky guys enjoy habitats that are associated with rocky areas, so we are not getting the best estimate of populations in those areas. Dr. Pirtle is looking in to alternative methods to determine whether an areas of the seafloor is untrawlable or trawlable using the mulibeam sonar. Not only is she looking for areas that can now be considered trawlable, she’s also using the data she collects to determine certain seafloor characteristics. Hardness, roughness, and grain size are all data that can be collected using the acoustic transducers. This information will help her to determine the relative trawlability of an area, as well. Therefore, the groundfish survey benefits because she is either finding areas to be trawlable (thus, they can now sample there) or somewhat trawlable, which can tell them ahead of time that alternative sampling methods might be needed in a particular area.
Her research is also concerned with developing alternative sampling methods for untrawlable locations. These methods could involve a combination of acoustic seafloor mapping to characterize seafloor habitats for groundfish, acoustic midwater data (to observe the fish that like to hang out on tall pinnacles and rocky banks) and, the most fun method – dropping a camera to the ground to identify species and biomass assessment (which is a fancy term for seeing how many fish are in a particular area). Improved understanding of groundfish habitats can lead to better management models, and the work Dr. Pirtle is doing can also contribute to conservation of areas that are sensitive to fishing gear that touches the seafloor.
The area that Dr. Pirtle decided to survey this evening was an area that was deemed to be untrawlable surrounded by many trawlable areas. These areas are often good candidates for mapping and camera surveys because both untrawlable and trawlable seafloor types are likely to be encountered, so the area can more easily be compared against existing data. We began our transects – driving transects with the ship over the area while sending sound waves to the bottom of the ocean to figure out differing ocean depths and seafloor type. Transect lines are close together and driven in a pattern similar to mowing a lawn, which gives Dr. Pirtle 100% coverage of her targeted area. Dr. Pirtle selects a location to drop a CTD – Conductivity, Temperature, and Depth meter – usually in the middle of the mapped area. The CTD is used to estimate sound speed in the location she is mapping. This is important because ocean depth is measured by the amount of time it takes for a sound wave to leave the ship, bounce off the ocean floor, and return back to the ship.
She then selects three to five areas to conduct camera drops. The camera travels to the bottom of the ocean where she can see if the area is untrawlable or trawlable based on what the camera shows her. I, on the other hand, get to see deep ocean critters in their habitats, which is also very cool. There are two types of camera drops – ones that record the information and then get played back later, and real-time camera drops where we can literally watch the camera make the trek to the bottom of the ocean in real-time. Dr. Pirtle uses the camera data to “groundtruth” or check the seafloor type against her acoustic map, to identify fish and other animals in the area, and to observe how species use the seafloor habitat.
As my shift was coming to a close, I could barely keep my eyes open, but I didn’t want to miss this. Tonight, we dropped the live camera into the depths. I stayed awake for the first drop so I could see what these operations looked like. Dr. Pirtle expertly maneuvered the camera into the deep using something that looked much like an old-school Atari controller.
As the camera dropped, we saw a few pollock and some other unidentified neritic creatures, but the real fun started when we got to the bottom. It was intense as Dr. Pirtle relayed information back to the bridge about the direction in which to travel, holding the ship still in the waves and currents when she wanted to examine an area more closely, and communicate with the technicians on the hero deck to relay the height that she wanted the camera held at. We saw all sorts of interesting creatures on the ocean floor – some arrowtooth flounder, a halibut, and Pacific Ocean Perch. We also observed beautiful cold-water corals and sponges that form a living component of seafloor habitat for many marine animals, including our target – rockfish. We even saw a shark! It was completely worth getting to bed a little bit later to see this incredible work in real-time.
On a side note, in a previous leg of the survey, Dr. Pirtle and her colleague from UNH CCOM, Glen Rice, found an underwater pinnacle that was later determined to be a navigational hazard! This pinnacle came so close to the surface of the water that in a “perfect storm” of low tide and a large enough ship with a deep enough hull, it could have unknowingly collided with this unmapped pinnacle – which could have potentially been disastrous. Glen, a NOAA hydrographer, was able to update the navigational charts in the area, alerting ships to the pinnacle’s presence. It just further supports the idea that the our oceans are so vastly unexplored – there is so much we don’t know about the feature that takes up the biggest portion of our Earth! I asked her if she named it because she discovered it – I quickly learned that just because you find something in the Ocean, it doesn’t mean you get to keep it. Apparently, you can’t name it, either. But I still called it Pirtle’s Pinnacle. I think it has a nice ring.
Personal Log
It was a sad day today watching the scientists pack up and box and tag the lab equipment and computers. As everyone bustled about, I spent some time hanging out for the last time on the bridge, in the galley, and in the fish lab thinking about my journey coming to its close. Although we spent the majority of it tied to the dock, I am so grateful for the opportunities we experienced that we otherwise would not have – it was a blessing in disguise, because we really got to experience all of Kodiak, and much of the bays and inlets around the island from the ship. The pictures will bring no justice to the beauty I’ve experienced in the last three weeks, whether it was walking along a beach with wild horses or staring in all directions to find nothing but water for as far as the eye could see. I spent an hour one night on the bridge watching the Leonids streak across the sky – a front row and first class seat, in my opinion. I never though that dodging whales would be an area of concern in my small life until we sailed through pods of them every day. If you would have told me three years ago I’d be petting an octopus three weeks ago, I would have called you a fool. If you would have told me three hours ago that this experience would be coming to a close three minutes from now, I would believe you even less. In the last three weeks, I have never laughed harder, worked more eagerly, or learned more with and from these incredible individuals who call this ship Home. As I quietly stood on the bridge watching the fast rescue boat dart off to the docks, I remembered the last time it was in the water watching carefully over us as we swam around the ship in our gumby suits. As we drove silently through the still waters to the city docks, we bade farewell to the animals that accompanied us on our trips – otters, eagles, puffins, and even sea lions gathered around to see us off to our homes and families. Or, they just so happened to be there looking for food and doing other instinctual things, but I do really think I saw an otter wave me goodbye.
Thank you so much to the crew and scientists of the Oscar Dyson – you fed my soul this summer and rejuvenated me in a way I never could have imagined. I am more revived today than I was on the first day of my second year of teaching (because, let’s face it, the first day of your first year you spend most of your time trying not to vomit) and I owe it completely to the Teacher at Sea Program and to all of the fine people I got to work with. To my partner in crime, Cat Fox – I’ll see you when we’re landlocked again! It was a total blast working with you. Thanks for always being there for a good laugh and for finding me so many salmon berries! If you are wondering whether or not you should apply for this program in the 2012 season – this is the advice I will give to you: JUST APPLY! It will change your life – promise.
Until our next adventure,
Staci DeSchryver
Did you know…
While I was working my night shift, I got the opportunity to help Dr. Pirtle “log the turns” of the ship as it was “mowing the lawn” in the zigzag pattern. This meant that I got to communicate with the bridge via radio every time they ended a transect and began turning in the opposite direction. I’m sure you may have predicted that this was most certainly a highlight of my work. It took great restraint on my part to behave myself with the radio, as everyone knows that radios can be a lot of fun. I did, however, let a few nautical words fly on the airwaves up to the bridge, one of them being “Roger, Willco.”
I had no clue where the origin of the word “Roger” came from. But now I do…
Roger, which starts with the letter R, means “Received”, which means, “I received your last transmission.” A long time ago, the radio alphabet (you know, Alpha, Bravo, Charlie, Foxtrot, Whiskey, etc.) used Roger to represent the letter R. It has since been changed to “Romeo.” Adding Willco to the end, means “I received your transmission, and I WILL COmply.” So saying that I received a message from the bridge and I was going to comply with it really made me look like a navigational moron – because they weren’t asking me to comply with anything. But I still had fun.
