Patty McGinnis: Let’s Go Trawling! May 24, 2013


NOAA Teacher at Sea
Patty McGinnis
Aboard R/V Ocean Starr
May 20 – 29, 2013

Mission: Juvenile Rockfish Survey
Geographical Area of Cruise: Gulf of Farallones
Date: Friday, May 24, 2013

Weather Data from the Bridge
Latitude: 37 ° 41.2’  N
Longitude: 122 ° 52.0’ W
Air Temperature: 10.5 Celsius
Wind Speed:  24 knots with gusts as high as 30 knots
Wind Direction: NW
Surface Water Temperature: 9.11 Celsius
Weather conditions: mostly cloudy

Science and Technology Log

Last night was my first night of actual work; work that is a challenge given the fact that the boat is moving constantly. There are quite a few tasks that the scientists hope to accomplish over the next week. They will be periodically be deploying a unit called the CTD. The CTD is a carousel that samples for conductivity/salinity temperature, and depth, at a continuous rate as it is lowered from the craft towards the bottom of the ocean floor. The unit transmits data to a computer program which in data analysis and for calibrating the instruments on the CTD itself.

This machine is called a CTD and measures conductivity, temperature, and depth

This machine is called a CTD and measures conductivity, temperature, and depth

The CTD also holds bottles are “fired” at various depths for the purpose of capturing a sample of sea water. The first of these occurs at the lowest point, which is approximately at 10-20 meters above the sea floor. The second bottle fires at the point at which the highest chlorophyll concentration was measured as the CTD made its way to the bottom. This chlorophyll max indicates the productivity created by photosynthetic organisms. The last bottle is fired at five meters below the surface. Water from the bottles is filtered and run through a benchtop fluorometer to obtain chlorophyll concentration which can then be used to estimate primary productivity, or the speed at which photosynthetic organisms produce new matter. Although this measurement may seem a bit boring to some, especially when compared to fish and marine mammals, it is important to remember that photosynthetic organism make up the basis of the food chain and without them no other organisms would exist in the oceans.

The Ocean Starr's floating laboratory

The Ocean Starr’s floating laboratory

My work, however, involves sifting the trawl catches. A trawl is a net that is dragged 30 meters from the surface of the water and is designed to catch organisms in the water column. The trawl is shaped like an ice cream cone with an end called the codend made up of a small mesh that prevents organisms from escaping. The scientist is charge of this part of the operations is Keith, an entertaining character who enjoys telling stories. He has informed me that trawling is conducted at night because if held during the day the fish can see the net and avoid it. Night trawls are therefore the preferred method for sampling for juvenile fish. There are several other people who assist in sorting the catches. Among them are Amber, a member of the NOAA core, Lindsay, who is a fisheries technician, and Kaia, who is a volunteer.

The water has been quite rough, so rough that we altered course last night and made modifications to our planned course which meant only four 15-minute trawls were conducted instead of the planned five. The majority of last night’s haul was krill; a shrimp-like organism about an inch or inch and a half in length. Mixed in with the numerous krill was a variety of organisms that included juvenile rockfish species, juveniles from other types of fish, market squid, Gonatus squid, and several octopi. In addition, we collected jelly-fish like organisms called ctenophores and colonial salps (a common name for any type of gelatinous zooplankton). Ctenophores have sticky cells that trap their food while colonial salps are filter feeders; both consume phytoplankton and zooplankton. Someone unfamiliar with these organisms might have difficulty believing that they are animals since they lack any readily apparent brain, eyes, ears, or mouth.

Does this look like an animal to you?

Does this look like an animal to you?

This salp is from the genus Thetys

This salp is from the genus Thetys

assortment of catch

Some of the typical organisms in a catch

                                       

Tonight we conducted a 5-minute trawl to “test” the waters for the presence of jellyfish. Since jellyfish can quickly clog a net, it is important to determine if the area is suitable for trawling before commencing operations. The exploratory trawl produced no jellyfish, so a 15-minute trawl has conducted. Unfortunately, little was obtained during the first trawl, while the second trawl yielded a number of market squid. We’ll continue operations throughout the evening. There is a good bit of down time between each trawl since we have to move to a different point between trawls and wait for the CTD to be deployed at each site. While I keep busy working on my blog, others surf the Internet, nap, eat a snack, or chat. Which would YOU do???

Lindsay and Amber record data

Lyndsey and Amber record data

Check out the krill!

Check out the krill!

I'm holding a juvenile rockfhish

I’m holding a juvenile rockfish

Personal Log

Yesterday morning Dave, one of the crew, went over the safety rules and emergency procedures with me. As part of my training I put on my survival suit which is designed to keep me afloat if there should be a reason to have to evacuate the ship. I hope I never have to actually use it, as is not the easiest item to put on. The large rubberized gloves make it very difficult to pull up the zipper (and it gives you some bad “hat hair!”).

Thumbs up for the survival suit

Thumbs up for the survival suit

I have quickly come to realize that the galley area is the place people come to congregate. Because of the various shifts, food is available 24-7. A whiteboard proclaims the meal times (6 am, 11 am, 5 pm, and 11 pm). The cook, Crystal, has been very accommodating regarding my request of non-dairy products; I have been treated to several non-dairy cheeses and was happy to see soy milk in the fridge. Others were happy to spot the special freezer that contains ice cream.

Along with the varied mealtimes comes varied sleep times; I will be working the night shift starting last night. I am a bit surprised to learn that the majority of the work is actually done during the night; while there are six of us who do the sampling for the night shift, there are only three who work during the day.

Shhhh! People sleeping!

Shhhh! People sleeping!

I have spent quite a bit of time chatting with Don, a fisheries biologist who dabbles in hobbies such as robotics, computer animation, and origami. His main job is to communicate with the captain regarding our course to ensure that we are trawling in the correct areas. He had warned me that things would get rocking once we are underway. Evidently a stubborn stationary high pressure system is responsible for rough seas. A small weather craft has been declared, and although we are not a small weather craft, we are not immune from the effects of the elements.

Don has been correct in his predictions. As I sit here typing in the laboratory, papers and magazines are sliding from one end of the table to the other as the ship rolls back and forth. The pitch today has changed from yesterday. The intensity is no doubt responsible for my discomfort. As the ship pitches unpredictably, I find that my stomach rolls as well despite a preventative course of seasickness medication. Even the old trick of looking out on the horizon did not help much this afternoon when the horizon disappeared and reappeared with each roll. I find it interesting that I am in minority and wonder if immunity to seasickness is something akin to immunity to poison ivy (not that I’m immune to that, either!). My friend Don assures me that things will be calmer soon; the swells are supposed to decrease substantially within the next 24 hours and as long as I “don’t mind a little rain” things should be improving.

Despite this, I am enjoying the friendship of my new acquaintances and have many new “firsts” such as holding an octopus in my hand, truly comprehending what krill look like, and seeing blue whales for the first time. Tomorrow will no doubt bring more surprises as I continue to adjust to life at sea.

Did You Know?

That fish are aged by their ear bones?

One response to “Patty McGinnis: Let’s Go Trawling! May 24, 2013

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