NOAA Teacher at Sea
Aboard NOAA Ship Oregon II
June 22 – July 6, 2017
Mission: SEAMAP Groundfish Survey
Geographic Area of Cruise: Gulf of Mexico
Date: June 25, 2017
Weather Data from the Bridge
Latitude: 28 30.0 N
Longitude: 94 00.4 W
Air temp: 26.7 C
Water temp: 28.8 C
Wind direction: 130 degrees
Wind speed: 14 knots
Sky: rain squall
Science and Technology Log
We left port Friday evening and by 10:00pm we were fishing. We move from stations to station, often in a zig zag pattern to retrieve our samples. As I mentioned in a previous blog, the stations we will visit are randomly generated for us. I will use this post to give you an idea of what we do at each station.
As we come upon a station, we first deploy a scientific instrument called the CTD, which stands for conductivity, temperature, and depth which it measures. Additionally, this instrument measures dissolved oxygen. During day light hours, we also take additional environmental data including water color, percent cloud cover and wave height. At least once per day, we take a water sample which will be titrated using the Winkler method to double check our dissolved oxygen readings. The CTD is first calibrated at the surface for three minutes, then lowered to approximately two meters above the bottom, with a maximum depth of 200 meters. Teamwork is critical here as the officers in the bridge announce that we have arrived at a station. The Science Field Party Chief (FPC), Andre, tells the fisherman the depth and watches the data come into a computer in the dry lab near the stern. They are all in radio communication to make sure everything goes smoothly.
Then the fishermen prepare to deploy a 40-foot trawl within a 2.5 mile radius of the station coordinates. Again, with communication from the fisherman, bridge and the FPC, the trawl is lowered into the ocean and moves along the bottom collecting organisms for exactly 30 minutes after which the trawl is raised and the net is brought onto the boat. The organisms caught in the net are then released into baskets,which are weighed on deck to get a total mass for the catch.
Then the fun begins! The full catch is poured out into the trough or if big enough, brought in via a conveyor belt. If the catch is 24 kg or under, we will log the entire catch.
If it is over 24 kg, then we will split the catch and log a representative sample. When splitting the catch, we first place all the organisms in the trough and roughly divide the catch in half. Before we send the half that we will not log back to the ocean, we must pull out commercial species, such as shrimp and snapper, and any individual species not found in the half we will log. Then we take the half of the catch that we will log and start the sorting.
We sort all organisms that are the same species into one basket, then count and take a total mass for each species group. You can see images below of a sorted catch.
For most species, we will sample up to 20 random individuals. We record length for all 20 and then take a mass and sex every fifth organism. Logging is a bit different for shrimp, we will record length, mass and sex for all organisms up to 200 individuals. We will do the same for any other commercial species.
We use a Limnoterra measuring board with a magnetic wand which gives an accurate length by connecting to a magnetic strip on the board. This tool saves a lot of time and allow us to get accurate measurements.
In future posts, I’ll talk more about what we are finding and learning from our data.
I am starting to find my sea legs. The seas were a bit rough as we left port after the storm. It was touch and go for the first 24-36 hours, but with the help of Meclizine (a motion sickness medication) and sea bands (wrist bands that push on a pressure point in your wrist) I am now feeling pretty good. I’m also getting used to the constant movement of the Oregon II which makes everyday activities like walking, showering and sleeping quite interesting. When I lay down in bed and close my eyes, I can feel the troughs of the waves push me down into my mattress and then I spring up at the tops of the waves. It is very relaxing and helps lull me to sleep. When showering, I frequently need to hold on so as to not fall over. As some of you know, I have a habit of moving pretty fast around school. Often in a rush to check items off my to-do list or get to my classes. On the boat, we need to move slowly due to the constant motion. You also never know when someone is going to open a door into the hallway or come around the corner. There is not much space, so you must move slowly and cautiously.
I am also getting use to the fish smell in the wet lab where I spend most of time when working. I’m on the day shift, which runs from noon to midnight. I’ve tried to soak up as much information as I can over the last couple days and have really enjoyed the learning. The hardest part for me is trying to learn scientific names for the 30-40 species we find in each catch. The Latin names go in one ear and out the other. Having never worked with fish, this part pretty challenging, but luckily Andre is very patient and always willing to answer my questions. My day-shift teammates, Tyler, David and Sarah, are terrific, keep the atmosphere fun and teach me each day. It has been really interesting to see the increase and decrease of certain species from different stations.
Did You Know?
The Texas shrimp fishery closed on May 15, 2017 and will re-open on a yet to be determined date in July. This is what is referred to as the “Texas Closure”. The shrimp data that we are collecting will be sent to the state to help them determine the health of the fishery and when to open it back up. According to the Coastal Fisheries Division of the Texas Parks and Wildlife Department (TPWD), “The closure is designed to allow escapement of shrimp out to the gulf where they can grow to a larger, more valuable size before they are vulnerable to harvest. The goal is to provide shrimp of a size that are more valuable for the shrimping industry while ensuring sustainable stocks in the future.”
Dawson Sixth Grade Queries
How many different species did you find? (Owen, Sylvia, Tyler, Maylei, Ben)
The number of species we find varies with each trawl, but recently we have been finding about 35-40 species per trawl. The picture below show the diversity a typical catch.
What organisms other than fish did you find? (Badri, Tyler, Alexa, Lorena, Wanda)
We find many other species besides fish. Some of the more common groups of organisms we find are squid, jelly fish, shrimp, sea stars, scallops, crabs, and vacated shells. Occasionally we catch a small shark or sting ray.