cod end – Page 2 – NOAA Teacher at Sea Blog

July 24, 2010March 12, 2021

Story Miller, July 23, 2010

NOAA Teacher at Sea: Story Miller
NOAA Ship: Oscar Dyson

Mission: Summer Pollock III

Geographical Area: Bering Sea

Date: July 23, 2010

Time: 1240 AKST

Latitude: 60°30N

Longitude:176°29W

Wind: 8 knots (approx. 9.21 mph)

Direction: 156° (SE)

Sea Temperature: 8.9°C (approx. 48°F)

Air Temperature: 9.2°C (approx. 48.6°F)

Barometric Pressure (mb): 1008

Wave Height: 0.5 feet
Wave Swell: 5 – 6 feet

Scientific Log:

Survey Tech Robert Spina and Fisherman Mike Tortorella deploying the CTD

We started the morning by dropping a CTD (Conductivity, Temperature, Depth) and monitoring the salinity of the ocean, the temperature, and depth. Salinity, the amount of salt in the ocean, is important as the higher the salinity the more conductivity it possesses. Conductivity is necessary for many things such as scientific observation and for marine life. For example, the transducer we use to send pings of energy through the ocean relies on conductivity and sound tends to travel better through waters with a higher salinity. Sound traveling through water is also important for animal communication. Salinity can influence the presence of fish species due to the different ways they process the water (think about freshwater fish versus saltwater fish). Water temperature is important for observing climate change. Because salinity affects the density of water (My students: remember the lab where we floated the egg with salt), it can change the temperature at which the ocean freezes. A simple example is that plain distilled water freezes at 0°C but the ocean at the surface typically begins to freeze at -1.1°C. As the water depth increases, so does the salinity and therefore as the temperature decreases the ocean does not freeze. We also launched an expendable bathythermograph (XBT) which measures depth and temperature at a deeper level than the CTD. These two tests are used to characterize the Bering Sea shelf environment.

Approximately six hours later we spotted our first school of pollock. We shot the AWT and caught a lot of two year-old pollock and a few one year-olds! The water temperature where they were located was about 2.5°C. I quickly donned my foul-weather gear and ExtraTuffs (rubber boots) and was ready to sort fish. From one sample, we sorted the fish, separating the small one year-olds from the two year-olds. Second, we cut open the fish to locate ovaries or testes. The males and the females were separated into bins and we fondly refer to the males as “Blokes” and the females as “Sheilas.” We measured their length and entered the data into the computer. With another sample, we sexed the fish, measured their length, extracted stomach samples to see what they are eating and to collect plankton samples, and last we extracted the otoliths. Otoliths are ear-bones and they are used to measure age, very much like looking at tree rings to find the age of a tree.

Me sorting the 1 year from the 2 year-olds

The walleye pollock observation has been conducted each summer since 1979 by the Midwater Assessment and Conservation Engineering (MACE) as a program of the Alaska Fisheries Science Center (AFSC) to estimate pollock abundance and distribution. The Oscar Dyson is following a route consisting of evenly spaced (20 nautical miles) parallel transects to estimate the pollock population over the entire Bering Sea shelf. So if you are tracking the ship using “Ship Tracker” this is why we are sailing in a strange pattern!

Personal Log:

Yesterday I was slightly anxious because I chose to experiment with my sea tolerance and not take the seasickness medication. Of course the seas decided to be a little more active as we began our pollock transit. Combined waves reached 10-12 feet and I just ate plain rice and bread for supper! Today the waves are more gentle and my stomach is very excited about that! Up on the “Bridge” where the controls for driving the boat are located tends to rock with the waves the most and it was fun to try and type my blog while attempting to keep my balance! However, by the end of the day, I was well enough to help “supervise” ENS Payne in the construction of chocolate chip cookies during my time off!

Dissecting the fish was incredibly fun and I cannot wait to have my students try their hands at it! I was very excited to extract otoliths because those particular bones were the fossils we used to identify the different fish species at the Always Welcome Inn in Baker City, Oregon when I was conducting research in college! To see those fossils go to the following website:

http://www.eou.edu/geology/index.html

Tomorrow we will be crossing the International Dateline and theoretically will have traveled into the tomorrow of tomorrow. The Oscar Dyson has become my time machine!

Image produced by the echo sounder telling us we have pollock! Notice how it looks different from the view in the previous blog.

Animals Viewed Today:
Least Auklet
Laysan Albatross
Fork-tailed Storm Petrels
Northern Fulmars
Short-tailed Shearwaters
Walleye Pollock

Something to Ponder:
Have you ever ordered pollock? How many of you have eaten fish sticks or surimi? Most likely you have eaten pollock and thought it was cod! Where does pollock fit in the food chain in the wild?
Also, how do you know when you have crossed the International Dateline? (Hint: check the data at the beginning of my blogs.)

June 27, 2010April 15, 2021

Deborah Moraga, June 27, 2010

NOAA Teacher at Sea Log: Deborah Moraga
NOAA Ship: Fulmar
Date: July 20‐28, 2010

Mission: ACCESS
(Applied California Current Ecosystem Studies)
Geographical area of cruise: Cordell Bank, Gulf of the Farallones and Monterey Bay National Marine Sanctuaries
Date: June 27,2010

Weather Data from the Bridge
Start Time: 0700 (7:00 am)
End Time: 1600 (4:00 pm)
Position:
Line 10 start on western end: Latitude = 37o 20.6852 N; Longitude = 122o 56.5215 W
Line 10 end on eastern end: Latitude = 37 o 21.3466 N; Longitude = 122o 27.5634 W
Present Weather: Started with full could cover and cleared to no cloud cover by mid day
Visibility: greater than 10 nautical miles
Wind Speed: 5 knots
Wave Height: 0.5 meters
Sea Water Temp: 14.72 C
Air Temperature: Dry bulb = 14 C Barometric Pressure: 1013.2 mb

Science and Technology Log
We left Half Moon Bay at 0700 (7:00 am) to survey line 10. We traveled out to about 30 miles offshore then deployed the Tucker trawl.

When the team deploys the Tucker trawl the goal is to collect krill. They are relying on the echo‐sounder to determine where the krill are located in the water column. The echo‐sounder sends out sound waves that bounce off objects in the water and works much like a sophisticated fish finder. Dolphins hunt for their prey in much the same way. A computer connected to the echo‐sounder is used to display the image of the water column as the sound waves travel back to the boat. By reading the colors on the screen the team can determine the depth of krill.

The scientists send weights (called messengers) down a cable that is attached to the Tucker trawl as it is towed behind the boat. Once the messenger reaches the end of the line where the net is located, it triggers one of the three nets to close. Triggering the nets this way allows for the researchers to sample zooplankton at three different depths.

image of water column on computer screen — Image of water column on computer screen

When the cod‐ends of the nets were brought onboard Jaime Jahncke (scientist for PRBO Conservation Science) examined the contents. Some of the organisms that were collected were… — When the cod‐ends of the nets were brought onboard Jaime Jahncke (scientist for PRBO Conservation Science) examined the contents. Some of the organisms that were collected were.

• Thysanoessa spinifera – a species of krill

• Crab megalopa larvae
Euphausia pacifica – a species of krill

July 3, 2009April 5, 2021

Ruth Meadows, July 3, 2009

NOAA Teacher at Sea
Ruth S. Meadows
Onboard NOAA Ship Henry B. Bigelow
June 12 – July 18, 2009

Mission: Census of Marine Life (MAR-Eco)
Geographical Area: Mid- Atlantic Ridge; Charlie- Gibbs Fracture Zone
Date: July 3, 2009

Weather Data from the Bridge
Temperature: 6.2^oC
Humidity: 81%
Wind: 16.47 kts

This is one of the glass floats encased in plastic that can withstand the pressure of the deep waters.

Science and Technology Log

High winds and high waves put a temporary stop to our fishing with the nets. When the waves are too high, the safety of the crew comes first and we wait for the weather to clear before we can start using the trawl again. The waves finally calmed down enough for the net to be used today. We are using a different type of net to fish the deep bottom (benthic trawling) than was used to fish the mid-water (pelagic trawling). This net is much simpler in design. It is a very large net lowered to the bottom of the ocean and then pulled behind the ship. The top part of the net is held open by floats. These floats were bought specifically for this cruise. The pressure on the bottom of the ocean is so great that normal floats would collapse. The new floats are made of glass spheres with a hard plastic covering. Only glass can withstand the amount of pressure that is found at these depths.

This is the net used for deep bottom trawling that has the yellow floats attached to it.

There are rubber tire-like rollers that move along the bottom to help prevent snags and also to stir up the sea floor and cause the fish and other organisms to move into the net where they are then funneled back into the narrow end of the net (cod-end). There are weights on the bottom section of the net to keep it on the ground. Of course, there are always obstacles on the bottom of the ocean floor and occasionally the net will get caught on one of these. This is a particular problem here because of the mountainous terrain. When the net gets hung up the crew works very carefully to release it from the obstacle. Sometimes the ship moves backwards as the winches try to pull on the net to release it. Sometimes the ship moves in a circle to try and pull the net clear.

The full net after it’s been retrieved on deck.

So far the benthic net has gotten caught twice but the crew successfully retrieved the net without damage. Once the net is on deck, the cod-end is opened and everybody comes out of the lab with foul weather gear (waterproof boots, overalls, jackets, life preserver and hardhats) on to collect the catch. We use lots of baskets to do a quick rough sort of the organisms caught. If the net is full, it takes a while to complete the first sort. Some of the fishes are large and some of the organisms have been torn. The organisms found on the floor of the deep floor are very different from the ones found in the mid-waters. They are much larger in size and very different in coloration.

Personal Log

The scientific crew is divided into three groups. We have a “day” shift, called a watch, that works from 12 noon to 12 midnight, and a “night” watch that works from 12 midnight to 12 noon, and then one group that works whenever a net comes up. I am on the day watch and we have all gotten into a pattern of who does what in the lab. My watch chief scientist is Dr. Shannon Devaney from Los Angeles. She works at the Natural History Museum there. Dr. Amy Heger from Luxembourg, Tom Letessier from Norway, CJ Sweetman from Connecticut and Randy Singer from Georgia rounds out our crew. CJ takes DNA samples, Tom takes care of the crustaceans, Randy removes the ototliths (this helps the scientist figure out the age) from the fishes, and Amy and I use the computer to enter the data. With some species we remove the stomach, liver and gonads from the fishes. These body parts are then measured and either frozen or preserved for scientists that are not on the trip. It has been fun relearning how to do some of the procedures.

June 19, 2009April 5, 2021

Ruth Meadows, June 19, 2009

NOAA Teacher at Sea
Ruth S. Meadows
Onboard NOAA Ship Henry B. Bigelow
June 12 – July 18, 2009

Mission: Census of Marine Life (MAR-Eco)
Geographical Area: Mid- Atlantic Ridge; Charlie- Gibbs Fracture Zone
Date: June 19, 2009

Weather Data from the Bridge
Temperature: 9^oC
Humidity: 95%
Wind: 4.36 kts

Scientific and Technology Log

We are currently working in the pelagic zone of the ocean. Pelagic refers to the open ocean away from the bottom. The word pelagic comes from a Greek word that means “open ocean”. The pelagic area is divided by depth into subzones. .

The epipelagic , or sunlit zone, is the top layer where there is enough sunlight for photosynthesis to occur. From 0 – about 200 meters (656 feet)deep
The mesopelagic, or twilight zone, receives some light but not enough for plants to grow. From 200 – 1000 meters (3281 feet)
The bathypelagic, or midnight zone, is the deep ocean where no sunlight penetrates. From 1000 – 4000 meters(13,124 feet)
The abyssal zone is pitch black, extremely cold and has very high pressure. From 4000 – 6000 meters.(19,686feet)
Hadalpelagic zone is the deepest part of the ocean. These zones are located at trenches where one tectonic plate is being subducted under another plate. 6,000 meters to over 10,000 meters. (35, 797 feet)

Setting up the net that will collect organisms

Today we are using a special trawling net to capture organisms that live in the mid-water area around 3000 meters deep. The closed net is lowered slowly from the rear of the ship until it arrives at the correct depth. The length of the wire released is measured by the winches as they unwind. A timer is used to open the cod-ends (containers at the end of the net). It is then pulled underwater very slowly. The five cod-ends are set to open and close at different times so there will be samples of organisms from different depths. After a specific amount of time the net is slowly reeled in. It takes about 8 hours to fully deploy and retrieve the trawl. Each cod-end should have samples from different depths. Once the net is back on board the ship, it is very important that the material collected from each cod-end be kept separate and labeled correctly.

All the blue buckets contain various organisms

The second trawl came in around 4:30 in the afternoon. We were really excited to see the organisms that were collected in each of the cod-ends. Each container was emptied into a large bucket and a picture was taken to record the catch. One set of material was left out to begin sorting and the other containers were put into the freezer to remain cold. David Shale, the professional photographer for the cruise, selected the best samples to use for his photographs. Then the actual sorting began. Several of us would do a rough sort, all the crustaceans (different types of shrimp-like animals) in one container, fishes in another, and jellyfishes in another. After the rough sort then the final sort is started (dividing all the organisms into groups by specie or family).

Certain types of organisms were abundant – hundreds of them, others were rarer – only one or two of each species. As soon as we are finished with one species, information about them is entered into the computer (number, length, mass) and then the organism is saved for later investigations by either freezing or placing in a preservative. A printed label is included in all samples so they can be identified by name, depth and location of trawl.

Personal Log

Everyone on board the ship is always interested in any sightings of marine mammals. The officer on the bridge will often announce to the lounge area if he spots any type of animal, “Whales off the bow.” As soon as the announcement comes on, we bolt out of the lounge to the outside as fast as we can. Sometimes you are fast enough and sometimes you aren’t. The dolphins usually are the easiest to spot as they swim in groups and surface frequently as they are swimming. The whales, however, are a little more difficult to see. They are usually far off so the distance makes them difficult to spot. When they surface, the spray from the blowhole is usually your first indication of where they are. After that, most of them dive again and you may not get a second chance to see them. So far the type of whales spotted have been pilot whales, sei whales and a sperm whale. They knew it was a sperm whale because the spray from the blowhole was at an angle. It is much more difficult to see these animals than I thought it would be. It is like trying to find a needle in a haystack – a very big haystack…

Did You Know?

The Mola mola is the heaviest known bony fish in the world. It eats primarily jellyfish which doesn’t have a lot of nutrition in is so they have to eat LOTS of them. It looks like a fish with only a head and a tail, no middle part.

Dr. Mike Vecchione took this picture of a Mola mola, a very large ocean sunfish, at the beginning of the cruise off the coast of Rhode Island.

June 14, 2009April 5, 2021

Ruth Meadows, June 14, 2009

NOAA Teacher at Sea
Ruth S. Meadows
Onboard NOAA Ship Henry B. Bigelow
June 12 – July 18, 2009

Mission: Census of Marine Life (MAR-Eco)
Geographical Area: Mid- Atlantic Ridge; Charlie- Gibbs Fracture Zone
Date: June 14, 2009

Weather Data from the Bridge
Temperature 7.6^o C
Humidity 94%
Wind 17.3 kts

Science and Technology Log

We are about half way to our location on the Mid-Atlantic ridge. Before we get there, we will do a comparative sampling over practice catch on the abyssal plain (a vast flat area on the bottom of the ocean). This will give us an idea of what lives in the deep open ocean away from the mid-ocean ridge for comparison with what we catch in our main study area. There has been very little sampling of the deep open ocean with large nets and not much is known about the animals that swim high above the bottom in such areas, even though they make up the largest living space on earth.

Various species that will have data recorded about them

All the scientists were divided into two groups. Each group will work a 12 hour shift. I will be working the 12 noon to 12 midnight shift. We met with our work group today to learn how to use some of the scientific equipment on board. The lead scientist for my group is Shannon DeVaney from Los Angeles, California. Her area of expertise is in mid-water fishes. We will be using a specialized computer program to record the data from the organisms that are caught in the nets. All the organisms will be at the end of the net in a special removable container called a cod-end.

This mid-water fish, a viperfish (Chauliodus sloani ), was 225 cm in length and had a mass 0.0230 kg. It was caught in an earlier tow test. Until today, I had only seen this fish in books. The teeth are really sharp and large for such a small fish. To learn more about the viperfish. Once the organism is measured and the information is recorded in the computer. A label can be printed and the animal will be either frozen or preserved for further investigation. Then it will be on to the next one.

Personal Log

Everyone is participating in the “Bigelow Olympics”. This is a fun competition for both the scientists on board as well as the crew. Today was the first event, a potato chucking competition. We each had 5 potatoes that we loaded one at a time to in a large slingshot to shoot at a target off the back of the boat. Each “hit” earned you 20 points for a possible total of 100 points – I only hit the target twice so I got 40 points. The event is open for 24 hours since some people will be working nights and some are working days. This is one of my attempts. Some people hit the target 5/5. There will be several more competitions, so maybe I will do better on the next one. If you look carefully, you can see my potato as it sails out to sea.

Here’s my potato as it flies toward the target!

The temperature has dropped some since yesterday, so it is difficult to stay outside for any length of time. Of course the wind is always blowing but sometimes you can find a place that is protected from the wind to enjoy some outdoor time. We all want to see icebergs and we may be in the area by Monday or Tuesday.

Did you know?

Did you know that icebergs are composed of fresh water? The density of fresh water is less than the density of seawater which is why the iceberg floats.