Chris Murdock: We’re not in Kansas (or Iowa) Anymore, June 12, 2017


NOAA Teacher at Sea

Chris Murdock

Aboard NOAA Ship Oregon II

June 7 – June 20, 2017

Mission: SEAMAP Groundfish Survey

Geographic Area of Cruise: Gulf of Mexico

Date: June 9 – June 12,  2017

Weather Data from the Bridge

Latitude: 27.0532N
Longitude: 96.3602W
Sea wave height: 4-6 ft
Wind Direction: 17 degrees
Windspeed: 17.31 knots
Air Temperature: 28.2 C
Barometric Pressure: 1010.9 mbar
Sky:  Overcast

Science and Technology Blog

The main focus of this research cruise is stock assessment in the Gulf. This is done using a trawl net. Trawl nets are large nets with the intention of collecting a wide variety of organisms. The specific type of system used aboard the Oregon II is called an otter trawl, which is the most common type of trawl used in the Gulf of Mexico to harvest shrimp. This enormous net forms a large cone shape once deployed. A trawling net has several main components: The first are two areas called the headrope (top line) and footrope. The headrope has floats attached to it that provide flotation to the top portion of the net. The footrope has long chains (often called tickler chains due to the fact that they “tickle” the bottom of the ocean to stir up sea life) on the bottom side of the net. Attached to the net itself are large wooden boards, called otter boards that are located on the main cable between the ship and the net. Water resistance forces the doors to spread and open the net. Inevitably, the organisms caught get held in the cod end of the net, which is the tip of the cone.

Trawl-Diagram

An Otter Trawl (Terraproject.com)

 

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One of Oregon II’s trawl nets. These are switched out every ten tows to check for any structural issues.

The types of organisms caught depends on both the depth of the net, as well as the mesh size (the spaces in between the net). All trawls on this cruise are done with the intention of collecting the three main commercial shrimp species of the Gulf, all under the genus Peneaus, which I will focus on in another blog post. The OOD (Officer Of the Deck) looks at the fathometer and electronic chart to determine how much scope to put out, and then  relays pertinent water depth information to the deck crew, who then release the proper amount of tow line to bring the net to the desired depth. The net is carried behind the ship for 30 minutes at a speed of 2.5-2.8 knots. At that time, the dry lab relays to the deck to “haul up” the net. Depending on the depth the net is currently at, this can take almost a half hour!

Once the Otter boards have reached the surface, the net is then pulsed. This means that the ship returns to a speed of 6-8 knots with the intention of pushing the catch down into the cod end. At that time the ship slows again and the crew hauls the load onto the deck. This entire process is repeated at predetermined locations called stations. If all runs smoothly a typical 12 hour shift will run through 5-6 stations. I will focus about the actual process of sorting the catch in future blog posts.

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Pulling the haul aboard

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Pulsing the tow

 

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A beautiful Gulf sunset behind the trawling gear

Personal log:

The first few days of real work are in the books! I have genuinely loved every minute of my time here on the Oregon II so far. I am assigned the day shift, which is 12 noon to midnight. This is most similar to my normal schedule back in Iowa. Thankfully, I haven’t had to adjust my sleep schedule as a result. It has allowed me to get into a fairly constant rhythm on board. My pre-work schedule typically consists of waking up around 8:30am, eating a light breakfast, working out, and doing work on this blog. I must say the amount of time I have to write meaningful posts is not nearly as much as I anticipated. I could very easily spend all of my waking hours dedicated to uploading photos and videos and writing. I have been keeping a journal on the cruise whenever I have free time so I can go back and elaborate.  Besides sorting out time management issues, everything else has been fantastic!

 

One of the biggest unexpected aspects of the cruise so far has been the food. I was anticipating eating a relatively basic diet while onboard. Boy was I wrong! The food has been absolutely fantastic, above and beyond my wildest expectations. That is in no short part to the wonderful stewards onboard, Arlene and Valerie. They bend over backwards making sure the crew of over 30 people are well fed. Every day has different food, and they are all very accommodating to any dietary restrictions. Roasted Duck is on the menu tonight, and I for one cannot wait!

I don’t know what I was expecting in terms of the type of work I would be doing, but this wasn’t it. I mentally prepared myself to become an expert at shrimp, but in reality I need to become an expert in latin. I routinely make my students memorize certain scientific names to organisms, but never to this extent. The first day of sorting I will admit was very overwhelming. Andre DeBose (the FPC) kept rattling names off to me like Synodus foetens, or Lutjanus campechanus, and all I kept saying to myself is “how in the world am I going to remember this”!? The first name I memorized was the Mexican flounder, or Cyclopsetta chittendeni. The first time I heard that my immediate though was “cyclops chicken dinner”? And just like that, I memorized my first species. After that if felt like every haul I was learning more and more. I am nowhere close to having them down, but I am making serious progress.

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Cyclopsetta chittendeni or the “Mexican Flounder”. The defining characteristic of this fish is the Sombrero-shaped spots around it.

It was so exciting sorting through our various hauls, and seeing dozens of organisms I have never heard of before. To me that is the best part of this whole experience so far. I get to see things that many people (and most of you back in Iowa!) never get the chance to see. How cool is that? I will do my best to post photos of every different species I encounter, but as you can imagine that will not be an easy task.

So far, the most memorable haul for me has been the one depicted below. I have always been a monumental shark fan and advocate, but the only experience I get with them is during Shark Week and when my biology class dissects Squalus acanthius (The atlantic dogfish shark). That all changed when we pulled up two Sphyrna tiburo (The bonnethead, which is a type of hammerhead) sharks. It was very difficult to contain my excitement, but I had to remain focused at the task at hand and get to work. I will speak more at length about the sorting process in my next post, but normally we do not get to save the animals as most are collected for further research back on land. Thankfully we got the sharks weighed and measured and successfully returned them to the sea unharmed. It was a moment I will never forget.  Again, I cannot say enough how lucky I am to get the opportunity to experience this amazing field work. I wake up each day like a child on Christmas Day, wondering what amazing secrets the Gulf has in store for me. The link to the haul can be seen here!: https://www.youtube.com/watch?v=l8hm1tmtFyY

 

Fish Species Identified Today:

 

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