measuring – NOAA Teacher at Sea Blog

July 17, 2017July 17, 2017

Anna Levy: First Day of Fishing! July 12, 2017

NOAA Teacher at Sea

Anna Levy

Aboard NOAA Ship Oregon II

July 10 – 20, 2017

Mission: Groundfish Survey

Geographic Area of Cruise: Gulf of Mexico

Date: July 12, 2017

Weather Data from the Bridge

We’re traveling through some mild rainstorms. Nothing extreme, but we do feel a little more side to side rocking motion in the boat (which makes me feel sleepy!)

Latitude: 29 degrees, 56.2 minutes North

Longitude: 86 degrees, 20.6 minutes West

Air temp: 24.7 degrees Celsius

Water temp: 30.1 degrees Celsius

Wind direction: light and variable

Wind speed: light and variable

Wave height: 1 foot (about 0.3 meters)

Sky: overcast with light rain

Science and Technology Log

Today I completed my first shift on the science team and we surveyed 3 complete stations. At each station, we carried out a multi-step protocol (or procedure). Here are the steps:

The Depth Contour Output graph displays data collected from one station.

Before we begin fishing, the ship conducts a transect (or cross-section) of the survey area, using multiple pieces of equipment to observe the ocean floor. This tells us if it is safe (for both ship operations and for fragile coral that may exist) to trawl here. If a coral reef or other large obstacle was present, we would see significant variation in the depth of the ocean floor. This “depth contour output” graph shows the data we collected at one station. How deep is the water at this station? Is it safe to trawl here?

The CTD collects information about water chemistry

We also use a collection of instruments called a “CTD” to collect information about the chemistry of water itself at different depths. This information is called the water’s “profile.” For fisheries studies, we are most interested in the amount of dissolved oxygen and the temperature at different depths. Why might this information be relevant for understanding the health of fish populations?

We also measure the water color using the Forel-Ule color scale by matching it to the samples shown in this photo. This gives scientists an indication of the amount of particulates, chlorophyll, and nutrients are in the water.

Once we determine it is safe to trawl, the ship returns to the starting location. We will trawl along the same path that we observed. Here’s the trawl net before it is lowered into the water. It will be pulled just along the bottom of the survey area, using tickler chains to agitate the ocean floor for benthic organisms for 30 minutes, and collecting whatever crosses its path!

Once the trawl is finished, the deck crew uses a large crane to pull the trawl on board. We all help to empty the net and place everything into baskets. Most of what we catch are biological organisms, but small amounts of non-living material (like shells, dead coral, and even trash) come up as well.

We then bring the baskets into the wet lab.

Baskets are emptied into a long trough with a conveyor belt

We dump the baskets into a long metal trough that has a conveyor belt at the bottom.

The catch is sorted into baskets by species

Next we sort the catch. Each species gets its own basket and we count the number of individuals for each species.

Then, it’s time for the tough part (for me at least) – every organism has to be identified by its scientific name. That’s a lot of Latin! Fortunately, Andre and the senior scientists are very patient and happy to help those of us who are new. It’s amazing how many species these experienced scientists recognize off the top of their heads.

We also have many field guides, which are books containing photos and descriptions of species, to help us.

For each species, we record the total number of individuals and total mass

We are interested in how much of each species are present, so we record both the total number of individuals and total mass of each species.

TAS Anna Levy measures the length of a flatfish using the Limnoterra Board

We also measure the length and mass of a sample of individuals. A handy device called a Limnoterra Electronic Measuring Board makes this process easy. We place the mouth of the fish on one end of this board and then touch its tail fin with a pen-like magnetic wand. The board then automatically sends the fish’s length to the computer to be recorded. We use an electronic balance that is also connected to the computer to measure and record mass.

A computer screen displays FSCS software

All of the information is recorded in a database, using software called FSCS (pronounced “fiscus”).

Many of the specimens we collect are saved for use in further research on land. Scientists at NOAA and other research institutions can request that we “bag and tag” species that they want. Those samples are then frozen and given to the scientists when we return to shore.

Any organisms or other material that remains is returned to the sea, where it can be eaten or continue its natural cycle through the ecosystem. The conveyor belt, conveniently, travels to a chute that empties back into the ocean. Now all that’s left is to clean the lab and wait for the process to begin again at the next station!

Our goal is to complete this process 48 times, at the 48 remaining stations, while at sea. 3 down, 45 to go!

Personal Log

This work has real highs and lows for me, personally. There are dramatic, hold your breath, moments like when equipment is lifted off the deck with cranes and lowered into the water. There is the excitement of anticipating what data or species we will find. My favorite moment is when we dump the buckets and all of the different species become visible. I’m amazed at the diversity and beauty of organisms that we continue to see. It reminds me of all of the stereotypical “under the sea” images you might see in a Disney movie.

The more challenging part is the pace of the work. Sometimes there are many different things going on, so it’s easy to keep busy and focus on learning new things, so time passes quickly. Other times, though, things get repetitive. For example, once we start entering all of the data about the individual fish, one person calls out the length and mass of a fish, while the other enters it into the computer – over and over until we’ve worked through all of the fish.

… but sometimes the work even stops altogether, especially when whether interferes.

Sometimes, the work even stops altogether, especially when the weather interferes. There have been mild rainstorms coming and going continually. It is not safe to have people on deck to deploy the CTD and trawling equipment when there is lightning in the area, so there is nothing for the science team to do but wait during these times.

Because the pace of the work is constantly changing, it’s difficult to get into a groove, so I found myself getting really tired at the end of the shift. However, an important part of collecting data out in the field is being flexible and adapting to the surroundings. There is a lot to accomplish in a limited amount of time so I keep reminding myself to focus on the work and do my best to contribute!

Did You Know?

When working at sea, scientists must use special balances that are able to compensate for the movement of the ship in order to get accurate measurements of mass.

To ensure that we are accurately identifying species, we save 1 individual from each species caught at a randomly selected station. We will freeze those individuals and take them back to NOAA’s lab in Pascagoula, where other scientists will confirm that we identified the species correctly!

Questions to Consider:

Review: Look at the “depth contour output” graph above: How deep is the water at this station? Is it safe to trawl here?

Research: What does “CTD” stand for?

Research: For fisheries studies, we are most interested in the amount of dissolved oxygen and the temperature at different depths. Why might this information be relevant for understanding the health of fish populations?

Reflect: Why might scientists decide to use three different pieces of equipment to collect the same data about the ocean floor? And, why might they have several different scientists independently identify the species name of the same individuals?

June 27, 2017June 27, 2017

Melissa Barker: Going Fishing, June 25, 2017

NOAA Teacher at Sea

Melissa Barker

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.

P1020827 — CTD instrument ready for deployment

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.

Releasing the catch

Massing the total 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.

P1020854 — Catch poured out into the trough

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.

P1020945 — Measuring a fish with the Limnoterra board

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.

P1020864 — Trying to sex a fish which can be sometimes be challenging

Personal Log

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.

P1020910 — Day shift crew from left to right: David, Tyler, Field Party Chief Andre, Sarah and Melissa

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.

P1020865 — Melissa and Tyler measuring fish in the wet lab

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.”

P1020883 — A large Brown Shrimp: *Penaeus aztecus*

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.

August 7, 2013March 12, 2021

Julia Harvey: Pollock on Deck/The Beautiful, the Strange and the Interesting, August 3, 2013

NOAA Teacher at Sea
Julia Harvey
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
July 22 – August 10, 2013

Mission: Walleye Pollock Survey
Geographical Area of Cruise: Gulf of Alaska
Date: August 3, 2013

Weather Data from the Bridge (as of 00:00 Alaska Time):
Wind Speed: 26.5 knots
Temperature: 13.6 C
Humidity: 84%
Barometric Pressure: 1014.6 mb

Weather Update:
A low pressure system is in the north Pacific and we are having increase winds and swells.

Science and Technology Log:

We listened. We fished. Now what?

Before reporting to the fish lab, I must gear up. Slime gear keeps the scales and goo off of my clothes.

Julia Harvey — That is me holding coral while in my slime gear.

Fish are emptied out of the net and onto the table outside the fish lab.

fish table — The fish caught in the trawl net are emptied onto this table.

We can control how many fish land on the conveyor belt by raising the table and opening the door.

The fish on the conveyor belt are separated by species.

Separating species — As the fish come off the table, Jodi and I separate the species while Darin weighs them.

In this blog we will focus on the pollock that were caught.

Pollock are gathered into baskets and weighed.

We group the pollock into 3 groups; age 1, age 2 and age 3+. Each group as an entirety is weighed. Each age group has a somewhat different protocol for processing. Fifty specimens that are age 1 will be measured with the ichthystick and 10 will also be weighed.

Fish that are age 2 are processed as age 1 but are also sexed.

When measuring a pollock on an icthystick, one measures from the head to the fork in the tail. The icthystick (a magnetic board for measuring fish) is connected to a computer that automatically records the data.

The larger pollock are grouped by sex. To do this, we cut open their abdomen and look for ovaries or testes.

sexing fish — The abdomen must be opened to determine the sex of the pollock

Then all of the fish (or at least 300) are measured on the icthystick. Forty will be measured and weighed and set aside for otolith removal.

Otoliths are made of calcium carbonate and are located directly behind the brain of bony fishes.

They are involved in the detection of sound and the process of hearing. The age of the fish can be established by counting the annuli much like one does when counting tree rings.

This age data allows scientists to estimate growth rates, maximum age, age at maturity, and trends of future generations. This data is vital for age based stock assessment models. These fish are weighed and measured. Otoliths are removed and placed in jars with glycerol thymol.

The jars have bar codes on the side so that the otoliths are linked to the fish’ weight, length and sex.

The otoliths are sent to Seattle for more detailed analysis of age. These results will be used to correspond length to age in the stock assessment report.

Sometimes, ovaries are removed and sent to other scientists for further histological study.

Other organisms that are caught alongside the pollock are counted and measured as well. The catch might include Pacific ocean perch, salmon, herring, viper fish, lantern fish, jellyfish, squid, and capelin. Below are a few of the normal finds and the rest can be found in my personal blog account “the beautiful, the odd and the interesting”.

Personal Log:

The beautiful, the odd and the interesting

This trip is not just about pollock. When we bring any of the nets in there is the possibility of weirdness and other things that catch my eye. Jodi is always filling me in on the uniqueness of our discoveries. And Darin lets me save organisms for photographing later.

My favorite find so far is the lumpsucker. As Jodi says, they have gentle brown eyes and they do. They also have suckers on the bottom that allow it to stick to substrate.

The Methot trawl went close to the bottom and picked up a handful of brittle stars. At first, when they were mixed with all of the krill, it looked like a bunch of worms.

Pollock do eat young pollock. We found evidence of this when Darin opened the stomach of an adult and discovered partially digested age 1 pollock.

pollock stomach — This pollock had feasted earlier on young pollock.

Lanternfish (Myctophids) make up a huge amount of the deep sea biomass. They have photophores along their sides for producing light.

The adult Pacific sandfish bury themselves in the sand with only their mouths protuding.

Prowfish lack pelvic fins. They have continuous teeth to feed on jellyfish.

When I think of deep ocean fish I think of the viperfish with its needle sharp teeth.

This cute mud star came up with the brittle stars. It was also referred to as the cookie cutter starfish because it resembles a shortbread cookie.

Salmon are good swimmers and usually escape the net. A few are caught at the surface.

When we were in Kodiak, I would watch the moon jellies drift by. Now we are catching several different species of jellyfish like this sunrise jelly.

Jodi always has a keen eye for finding nearly invisible creatures. The arrow worm is a voracious predator. They immobilize their prey with neurotoxins.

I had never heard of a sea mouse before this cruise. Now I have. Except it is not a rodent. It is a carnivorous worm that feeds on hermit crabs and other worms. It is also a scavenger like a vulture.

Some isopods are parasitic and will feed off of the blood of fish in the gill chamber. I prefer their cousins the pill bugs.

Did You Know?

When we are all measuring and weighing away in the lab, it sounds like a video game. Each machine has it’s own unique sound effects. This allows scientists to have confidence that their data was recorded.

machine noise — All machines have unique recording sounds