Air temp 45F, sea depth 59 m , surface sea water temp 44F
Catching the Tiny Fish in the Big Sea
For the past two days, I helped out Robert Levine, PhD Student of Oceanography at the University of Washington, working with NOAA Alaska Fisheries Science Center. We sent out a Methot net to catch juvenile fish today. In the below picture, taken yesterday, I am helping Robert assemble the Methot net.
Teacher at Sea Roy Moffitt helps assemble the Methot net
For catching fish a centimeter or two long, the net seems huge. The opening of the net is approximately 2.2 meters by 2.2 meters or 5 square meters. The net itself is approximately 10 meters long. The holes in the net are only 2 mm. This means anything bigger than 2 mm will be caught up in the net.
Example of an Echogram
Before sending the net into the sea Levine takes an echogram survey. He lowers the recorder overboard and the attached cable sends the results back to the computer on board. Two different wavelengths are sent out and bounce off anything in the sea column. The smaller wavelengths will show where any of the smaller fish are hanging out. The results give an accurate depth measurement of the ocean and shows small organisms at about 28 meters in depth. The net is then lowered into the sea and trawled at that depth for about 15 minutes.
Inclinometer
My task during the net deployment was to measure the angle of the cable entering the water by using a hand held inclinometer. It is important to keep the angle around 45 degrees to keep the proper depth.
Photos of today’s catch: at top left, a view of the unsorted bucket; top right, a petri dish with fish sorted by species; bottom, juvenile fish displayed on measuring tape
Today was not considered a high population area, but we were still able to catch some fish and more marine life. All contents end up in a canister at the end of the net in a big slurry of sloppy stew. In the picture of the bucket the fish are hidden within moon jellyfish and all the little black dots that are crab megalopa. Crab megalopa is the second life stage of a crab before transformation into juvenile crabs to start their life on the sea floor. For fish today what was caught in the net were juvenile Cod, juvenile flat fish, and Sculpin. (Shown in picture with the round dish.)
The goal of this fish collection is to verify the presence of juvenile fish and better understand the geographic range of fish during their life cycle. The exact identification of each will take some time and many of the tiny fish are frozen and sent out to labs for further identification. Levine will also be releasing several bottom-moored echo sounders during the trip. These instruments will be able to monitor the presence of fish and record that data over the year.
Now and Looking forward
Future specimen collections on this trip will be happening using the Methot net to verify distribution and seasonal movement of fish population in the Chukchi Sea.
NOAA Teacher at Sea Vincent Colombo Aboard NOAA Ship Oscar Dyson June 11 – 30, 2015
Mission: Annual Walleye Pollock Survey Geographical area of the cruise: The Gulf of Alaska Date: June 21, 2015
Weather Data from the Bridge:
Wind Speed: 6.02 knots
Sea Temperature: 9.99 degrees Celsius
Air Temperature: 9.06 degrees Celsius
Air Pressure: 1016.59 mb
Unimak Island at sunriseUnimak BightShishaldin Volcano – One of Alaska’s many active volcanoes
Science and Technology Log:
You are sleeping soundly in your bed. Awakening you is your phone ringing… it’s 5:30 am… that could only mean one thing, it’s the school calling to say school is delayed 2 hours… FOG. No, it’s not the kind of fog depicted in John Carpenter’s thriller; it’s the kind that the local weatherman says is a localized phenomenon that reduces visibility to less than a quarter mile. If you live on Delmarva, you have experienced this sort of fog and know that it can turn a normal commute into a complicated one.
Here in the Alaskan summer, especially the Aleutian Chain, Gulf of Alaska, and the Bering Sea, fog is a normal, and potentially ALL day event. The only constant on this research cruise so far has been waking up every day and watching our NOAA Corps Officers navigate through a very dense fog.
A view from the bridge of the fog. You can barely see past the bow
But what causes fog, and why is it so prevalent here?
Fog is most simply described as a cloud on the ground. It is made up of condensed water droplets that have encircled some sort of condensation nuclei (something water can attach to). On the open sea, that condensation nuclei is salt, which has upwelled (brought to the surface) from turbulent seas or breaking waves. That translates to the rougher the seas, the more chance there is for condensation nuclei, and thus fog.
Fog is able to be formed when the air temperature is cooler than the dew point. The dew point refers to the specific temperature which water can condense. Dew point varies with humidity and temperature, you can calculate dew point here.
Because the sun exposure is so long here in the Alaskan summer day, there is ample time for the sun’s radiant energy to heat up the upper layer of the ocean causing evaporation. The now warmer air, filled with water vapor, meets the cool waters of the Northern Pacific or Bering Sea, and bam, here comes a fog bank. The most common name for this type of fog is Sea Fog, scientifically called Advection fog. The combination of salt is especially important because salt is a unique condensation nuclei in that it will allow fog to form when the humidity is as low as 70%. It can also turn from a gentle fog to a dense fog in little to no time. Air movement, or wind can actually cause more fog, rather than the contrary belief it will just blow away.
As the day goes on, the fog lowers. Notice the sea is calm, and the dew point is raising.The sky is crystal clear, however the surface is still covered in dense fog
So what have I learned? NOAA Ship Oscar Dyson has a very loud fog horn which the NOAA Corps Officers sound on a regular basis during these conditions.
Here is what you need to know if you are ever on the ocean in a fog bank!
One prolonged sounding of the horn – this means “Hey! I am here and moving, don’t hit me!”
Two prolonged soundings of the horn – this means “Hey! I am a big boat, but not moving, don’t hit me!”
One prolonged sounding of the horn followed by two short blasts – “Hey! I am a big boat and am either towing something (like a fishing net) or lowered in my ability to maneuver. Stay away and make room!”
One prolonged sounding of the horn followed by three short blasts – “Hey! I am a big boat that is being towed. Stay away from me because I have no power!”
One short blast of the horn, followed by a prolonged sounding, then one short blast; or rapidly ringing of a bell for five seconds every minute – “Hey I am anchored over here, you can’t see me, stay away.”
Here the land is still covered. This is what is called radiant fog. The conditions on land are still perfect for fog to exist. Radiation fog typically disappears as the sun warms up the land. Under that fog blanket is another mountain.The sun is able to eliminate and produce fog
You have to trust the Radar
Personal Log:
The life at sea is quite interesting. Luckily we have every luxury of home on board the Oscar Dyson, to include internet (sometimes), hot showers, and a nice bed. I have also been introduced to the game of Cribbage, an apparent maritime tradition. I cannot say that I fully understand it, but there are bunches of ways the number 15 can be made.
Busy on the ship’s fantail
Fishing is life up here, and every day I can expect at least one or two trawls (pulling of a net behind the ship). I was introduced to what is called a Methot net, which is used for catching smaller organisms. I was able to look at Krill for the first time in my life the other day, a keystone organism for a lot of the Alaskan food web.
Krill!
Also very cool was seeing the MACE scientists use a cool underwater camera. Ever wonder what is under 300 meters of water? With this camera that can be deployed in less than 5 minutes, scientists can get a picture of the sea floor on a live feed.
Looking at the live feed of the sea floor
Meet the Crew:
Richardo Guevara. Richardo has been with NOAA for 7 years and is the Ship’s Electronics Technician. What does this mean? Richardo works on various systems on the ship that involve communications, such as radios, acoustics, data sensors, radar, telephones, televisions, navigation, and computer systems. Richardo is the IT guru and knows everything about the ship’s day to day mission with technology. Richardo works for NOAA because he enjoys the life at sea, its benefits, and the satisfaction of working side by side with scientists.
Richardo Guevara, Electronics Technician
Richardo is a 23 year veteran of the United States Air Force. During his service he gained a plethora of knowledge suited towards his current position on board the Oscar Dyson. Richardo was born and raised in Pensacola, Florida, but now resides on the Oregon coast. Richardo says that this job requires a lot of flexibility, and his time in the military gave him this valuable life skill. According to Richardo: “A lot of times people seem to get the notion that you must have college to succeed, but I do not have a college degree. I cannot understate how important it is to get your high school diploma and to value that. Then it is up to you to go your own way and have success.”
Meet the crew:
Kirk Perry. Kirk is the lead fisherman aboard the Oscar Dyson and is acting Chief Boatswain for our research cruise. Kirk has been with NOAA since 2004, and is in charge of any activity which takes place on deck. His job includes, but is not limited to, using fishing equipment, deploying science equipment, anchoring, net maintenance, standing lookout on the bridge, being a helmsman, managing a deck crew of 6, and operating a crane. Kirk joined NOAA for the adventure of a lifetime, to fish in Alaska. He never intended to stay this long but absolutely loves his job and he says working with scientists is very rewarding.
Kirk Perry, Lead Fisherman
Out of curiosity in the neighborhood, Kirk discovered the world of fishing and hunting from a Czechoslovakian neighbor in San Jose, California. Kirk started commercially fishing at age 10 in Monterey Bay, California and has not looked back since. He graduated from Cal Poly SLO with a degree in Natural Resources Management while on scholarship for college baseball. Kirk loves baseball and football and is a diehard San Francisco Giants and 49ers fan. He also isn’t too bad on the guitar either.
Kirk was my unofficial, but official Alaskan fishing guide. It was his handy work that set me up with rigs and a tackle for my Halibut at the beginning of my trip. Kirk and I have a lot in common and have had countless discussions about the outdoors. A fun fact about Kirk, he can identify any bird that flies by the ship, whether it’s out of necessity or because he has been hunting so long.
NOAA Teacher at Sea
Allison Schaffer
Onboard NOAA Ship Gordon Gunter September 14 – 27, 2007
Mission: Ichthyoplankton Survey Geographical Area: Gulf of Mexico Date: September 21, 2007
Weather Data from Bridge
Visibility: 12 nautical miles
Wind direction: E
Wind speed: 12 kts.
Sea wave height: 1 – 2 feet
Swell wave height: 2 – 3 feet
Seawater temperature: 29.0 degrees
Present Weather: Partly Cloudy
Science and Technology Log
Today we had the opportunity to try out two new sample methods. One method is along the same lines as the bongo and Neuston sample but this one is called a methot. A methot is 2.32 X 2.24 m frame with 1/8” mesh netting. The total length of the methot net is 43 feet. It’s huge! It works just like regular plankton net where it has a large opening and then as it moves towards the end it becomes more and more narrow and eventually ends at a collection container. The reason this is my first time doing one is because they are usually done only at night and since the net is so large they must be done in fairly deep water. The deck personnel helped us put the net in the water and then we waited. As the net was brought back on deck, we rinsed it down and collected samples the same way we would a bongo or Neuston sample. Of course with such a large net we collect bigger animals that we would with the other two. We did collect some fairly large fish along with smaller larvae. Our collection wasn’t the most excited some of the scientists have seen but to me, it was very exciting.
The second collection we took wasn’t a plankton collection but a water sample. It is important to know the physical and biological parameters of different areas when collecting. For this, we used a very large (and expensive) piece of technology: a CTD which stands for conductivity, temperature and depth. The CTD also measures dissolved oxygen and can do all of these measurements without actually collecting any water. We do however collect water to look at chlorophyll levels. The CTD frame has three bottles attached to the frame to collect water throughout the water column. Once we open the bottles on deck and set them, the lab scientist has the capability to fire the bottles shut at different depths. All measurements and water collection happen at three areas in the water column. One data and water collection is done at maximum depth, the second at mid depth at the third just a few feet from the surface. After all of the data has been collected, the CTD is brought back on deck where we bring the water samples up to the lab to test. It was definitely an exciting day on deck today.
Personal Log
It has one week since we left port in Pascagoula and I am having such a great time! I forgot how much fun field work is and how excited I get over the smallest things when it comes to animals. I am so fortunate to have such an experience and I can not wait to get some samples home to share with our students. I already have started making some lesson plans!
Addendum: Glossary of Terms
Visibility is how far ahead you can see from the ship. On a very foggy day you may only have a visibility of 10 ft whereas on a clear day you can see all the way to the horizon, or 12 nautical miles.
Wind direction tells you which way the wind is blowing from: 0° is north, 90° is east, 180° is south, and 270° is west.
Sea wave height is the height of the smaller ripples
Swell height is the estimates larger waves
Sea level pressure (or Barometric Pressure) indicates what the trend of the weather has been. High barometric pressure usually means sunny weather and rain can not build up in clouds if they are being squeezed together by high pressure. Low barometric pressure means rainy or stormy weather is on the way.
Present Weather is a description of what the day’s weather is.
– Courtesy of Thomas Nassif, NOAA Teacher at Sea, 2005 Field Season
Field Party Chief or FPC is in charge of the team of scientists on board the ship. This person oversees all activities having to do with collection of samples and is the go to person in case anything goes wrong that the scientists can’t handle. They also act as an extra set of hands when needed.
Bongo Net is two circular frames 60 cm in diameter sitting side by side with two 333 micron nets and a weight in the center to help it sink. At the base of each net is a plastic container used to collect all the plankton that can be easily removed so we can retrieve the samples
Lab Scientist is the scientist that stays in the lab to work the computers recording the data on sample time, sample depth and is the one that relays information to the deck personnel about when the nets have hit maximum depth. They keep watch in case anything goes wrong underwater.
Deck Scientist is the scientist out on deck getting the nets ready, rinsing the nets, collecting and preserving samples. They are the eyes on deck in case anything goes wrong at the surface or on deck.
Neuston Net is one net 1 X 2 meters with a 947 micron net. Neuston samples are done only at the surface and placed in the water for ten minutes.
