NOAA Teacher at Sea
Aboard NOAA Ship Henry B. Bigelow
September 7-19, 2014
Mission: Autumn Bottom Trawl Leg I
Geographical Area of Cruise: Atlantic Ocean from Cape May, NJ to Cape Hatteras, NC
Date: September 10, 2014
Weather Data from the Bridge
Present Weather CL
Visibility 10 +nm
Wind 025° 10kts
Sea Level Pressure 1016.2
Sea Wave Height 3-4 ft
Temperature: Sea Water 26.6°C
Air 24.8° C
Science and Technology Log
We are now “on the road again” trawling. The nets were lowered at about 7:30 am. I was surprised by how small our catch has been. The scientists are not at all surprised. They said because of the time of year, many fish are in the estuaries spawning (reproducing). Today we have been on the edge of the continental shelf off the coast of Delaware and Virginia. When we get in closer, the scientists say we will have a lot more fish in our net.
It is fascinating how they are selecting sites for sampling.The sea floor needs to be fairly flat to pull a net across. We learn what the bottom is like using sonar. A multi-beam sonar on the bottom of the hull is in the center of the ship. There is also a single-beam sonar there. They serve two different purposes. The single-beam looks straight down the water column. It is like a really bright penlight. This shows what is in the water column such as fish and plankton. It also can reach greater depths since its light is stronger. The multi-beam is more like a floodlight. It spreads out over the bottom revealing all the different levels of the ground. These sonar beams bounce off the bottom and send the ship information. The crew watches the sonar information and scouts for a good area to drop our nets. Of course, there are certain areas where samples need to be taken. They are trying to repeat a tow at the same time every year within a strata area. “So what is a strata?” I asked.
Strata lines are like lines on a topographic map on land. It is called a bathymetric map underwater. The lines on a bathymetric map are called strata lines. These are based on the different depths. The net needs to be pulled within the same strata at the same time each year. As long as a tow is within the strata the habitat is about the same. In order to get accurate population information, they must make at least two tows within a strata. Some of the strata are hundreds of square miles. Strata are the same depth range and habitat. Closer to the continental shelf, the strata are much narrower. Closer to shore, they are much wider. For example, strata 70 is 281 square nautical miles (nm). It is 55-110 m deep and is next to the shelf. However, strata 73 is closer to shore, is 2145 sq. nm, and is 27-55 m deep. Their habitats are different so random samples need to be taken within each.
So, I think of it like a chess board within a strata. If we want a random sample, we could drop a piece of soft clay from about a 1/2 m above the board. Where it hits is where we tow in that strata. Our first tow is at D5. The second piece of clay could fall on H2. So, there is where we would sample.
Then, when the ship is over top of the strata we will sample, it must find a safe area to tow which won’t tangle or break the net. You can’t get a sample with a broken net.
Notice the wires on the spools which haul the nets. On the first one the wire is tightly wrapped. On the second one the wire has a gap. This could lead it to break or more easily tangle. We are doing a deep tow tonight outside of the “normal” range of 366 m deep. However, it will not only give us new information, but will, hopefully, help rewrap the wire on the second spool so it will be tight. Have you ever tangled a loose fishing line on your reel? It is somewhat similar to that so we are trying to prevent this from happening later.
So, what have I been doing while waiting for a tow to complete? It depends. One time I told jokes with the scientists. Another I had a snack. Once I ate dinner. Right now, I’m working on my blog. Nap is not an option. I’ll explain that later.
It was a Win-Win Wednesday. We got some great fish by going deep, we explored some very deep water, the wire was rewound properly onto the spool, and we will have a shrimp fest tomorrow.
Meet the Crew
The old adage “an army runs on its stomach” holds true for a research vessel. Meet Luke Staiger, our 2nd cook. Luke is with the Bigelow on temporary assignment from the Reuben Lasker in San Diego. NOAA members get moved around short term as needed. Luke has been with NOAA for 12 years. He has been cooking since he was a kid. His most important tool is an 8″ all purpose knife. It must be sharp and long-handled. If he could invent the perfect tool for the job, what do you suppose it would be? That’s right, a knife that is comfortable to hold all day.
Luke worked in a buffet restaurant so this is the perfect situation for him since it’s all buffet. He worked his way up to cook after doing other jobs at the restaurant. I’m looking forward to a breakfast that he prepares since cooking breakfast is his favorite.
Luke recognizes how important the work is that NOAA does. We need to preserve our resources, such as water, he says. NOAA keeps an eye on things so we don’t lose sight of what matters. When not on a boat, Luke enjoys fixing up cars, especially adding stereo systems. Luke has an easy going personality and a ready smile, making it pleasant to work with him.
How did he find NOAA? Similar to others that I have interviewed, he looked online. NOAA has good benefits, you get to travel, and the experience is good. His advice to my students is to gain lots of experience in your field, even if it’s just volunteering. You will find work if you do a good job and have a lot of experience.
Remember I said I won’t get a nap during my 20 minutes between tows? It is interesting how our stateroom (cabin/bedroom) works. There are four of us in our stateroom. When I leave to go to work, I cannot go back until the end of my watch. I carry everything with me so it is like the private room for two other women. Then I only have one room mate. We get the room for 12 hours. There are curtains around our beds and we wear earplugs. I hardly know that the other scientist on my watch, Lacey, is even there. All I do is check to see if her curtain is closed. That means, “I’m asleep.”
Did You Know?
Did you know that there is an anchor-cleaning device onboard the ship? It sprays salt water at 150 psi (pounds per square inch). The anchor gets pretty dirty sitting on the ocean floor when we are at anchor. They don’t want all that dirt on the ship in the anchor locker, so it gets cleaned. A clean ship is a happy ship.
Question of the Day
Why would different depths affect which fish live there?
Sonoluminescence. This is short bursts of light from imploding bubbles in water (or in a liquid) when excited (moved around) by sound. A mantis shrimp is capable of sonoluminescence because the high speed of its front legs is capable of creating and rapidly shrinking air bubbles. The bubble looks like a spark underwater with no fire.
Something to Think About
If we don’t preserve our fisheries, which is what NOAA is researching, soon there won’t be any fish.
We used a deep-water protocol, which is between 183 and 366 m. If you are fishing in a strata that is 200 feet deep, would you fall in the deep-water protocol?
Animals Seen Today
Here are pictures of what we saw today in our really deep water trawl.