Anna Levy: What Tummies Tell Us, July 15, 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 15, 2017


Weather Data from the Bridge

Scattered, mild storms continue, causing some delays in our fishing. However, they do lead to beautiful sunsets!


Beautiful Gulf of Mexico sunset

Latitude: 29 18.790 N

Longitude: 84 52.358 W


Air temp: 28.7 C

Water temp: 29.7 C

Wind direction: light and variable

Wind speed: light and variable

Wave height: 0.3 meter

Sky: 80% cloud cover, no rain


Science and Technology Log


TAS Anna Levy removes the stomach of a red snapper.

Data about the number and size of individual organisms can tell us a lot about the health of an overall population of a species. However, it doesn’t tell us much about the role that species plays in its community. If we want to understand that better, we need to know more about how it fits into its food web – what it eats and what eats it. If you were trying to collect information about what a fish eats, where would you look first? Its stomach!

So, after we measure certain species, we dissect them and remove their stomachs. We place each stomach in its own tiny bag, with a bar code that identifies which individual fish it belonged to. Back at a lab on land, scientists will carefully examine the contents of the stomachs to better understand what each species was eating.


The bar codes that we use to label specimens.



This map shows the native range of lionfish. Credit:

For example, one of the fish currently under investigation in the Gulf of Mexico is the lionfish. This is an invasive species, which means that it is not native to the area. Its natural habitat is in parts of southern Pacific and Indian oceans, but it was first spotted in the Atlantic, off the coast of North Carolina, in 2002. Lionfish were most likely introduced to this area by humans, when they no longer wanted the fish as an aquarium pet. By 2010, its range had expanded to include the Gulf. And, with no natural predators in this area and rapid rates of reproduction, its numbers have increased exponentially.

Early dietary studies, which were focused on the lionfish in the Atlantic, show that the lionfish is a generalist. This means that, while it prefers to eat small reef fish, it is able to eat a wide variety of organisms including benthic invertebrates (like crabs) and other fish. This flexibility makes lionfish even more resilient and able to spread. These studies also found that lionfish stomachs were rarely empty, suggesting that they are highly successful predators, able to out-compete other top predators for food.

This has wildlife experts concerned about the impact lionfish will have on natural ecosystems. It is possible that lionfish will over-consume native species, causing native ecosystems to collapse. It is also possible that lionfish will out-compete and displace native, high level predators, like snapper and grouper. Scientists are working now to develop methods to try to manage this invasion.

Because ecosystems here are different from those in the Atlantic, scientists are now turning their attention to studying the lionfish in the Gulf of Mexico. The work that we did on the boat today should help them do just that!

To see the results of one such study, completed in 2014, see:

For more information and photos about the lionfish, please see:


Personal Log

Often times, we teachers struggle to convince our students that, while all of the modern technology we have is great, they also need to understand how to solve problems without relying on it. (Most of us have probably been on at least one side of the old, “no, you don’t need a calculator to multiply by 10!” argument at some point in life.)   Well, in the past couple of days, I’ve seen two great examples of this onboard the ship.

The first relates directly to our survey work. Our CTD, the equipment mentioned in last post, has two sensors that both detect how much dissolved oxygen is in the water. Having two instruments collecting the same information (sometimes called redundancy) is important, not only so that there is a back-up in case one breaks, but also so that we can tell if they are measuring accurately.

The two oxygen sensors have been reading differently – one was about 0.7 mg/L lower than the other. This is an indication that one needs to be calibrated – but which one? To find out, Alonzo Hamilton, one of the senior NOAA scientists, used a classical chemical analysis technique called titration.


This is the titration equipment found in the chemical lab on board the ship.

In a chemical titration, one substance is slowly added to another, while the scientist watches for a chemical reaction to occur. If you know how the two substances react, you can determine how much of the second substance is present, based on how much of the first was added to make the reaction happen.

Based on the results of his titration, Alonzo was able to determine which of the oxygen sensors was reading accurately. So, it definitely goes to show that there are important applications for that classic high school chemistry!


The binnacle that houses the ship’s magnetic compass.

The other example relates more to the ability to navigate the ship. NOAA Ship Oregon II is equipped with advanced electronic navigation software, Gyro compass, radar, and GPS systems. However, when I was exploring the top deck (flying bridge) of the ship, I came upon this strangely low-tech looking instrument. I asked ENS Chelsea Parrish, a NOAA Corps Officer and member of the wardroom, about it. She explained that it is called a “binnacle,” a safeguard that houses a magnetic compass! The magnetic compass is the same type of technology used by mariners back in the 1300’s. It is critical to have in case of a power outage or other disruption to the ship’s electronic navigation technology.



Did You Know?

While they typically live in cold waters, there is one pod of orca whales (aka killer whales) that resides, year-round, in the Gulf of Mexico. It’s rare to see them, but I’m keeping my eyes peeled!

Dolphins, on the other hand, seem to be everywhere out here. I’ve caught at least a glimpse of them every day so far. In fact, a group of them swam up to investigate our CTD today as it was being lowered into the water.


Questions to Consider:

Research: Some other famous invasive species in our oceans include the green crab (Carcinus maenas), killer algae (Caulerpa taxifolia), a jellyfish-like animal called a sea walnut (Mnemiopsis leidyi), a marine snail called rapa whelk (Rapana venosa), and the zebra mussel (Dreissena polymorpha). Where did each of these originate? How did they come to inhabit their invaded areas? What impact are they having?

Brainstorm: What measures could you imagine taking to manage some of these species?

Research: The specific type of titration used to determine the amount of dissolved oxygen in water is called the Winkler method. How does the Winkler method work?




Jennifer Fry, July 22, 2009

NOAA Teacher at Sea
Jennifer Fry
Onboard NOAA Ship Miller Freeman (tracker)
July 14 – 29, 2009 

Mission: 2009 United States/Canada Pacific Hake Acoustic Survey
Geographical area of cruise: North Pacific Ocean from Monterey, CA to British Columbia, CA.
Date: July 22, 2009

Weather Data from the Bridge 
Wind speed: 13 knots
Wind direction: 003°from the north
Visibility: clear
Temperature: 13.6°C (dry bulb); 13.2°C (wet bulb)
Sea water temperature: 15.1°C
Wave height: 1-2 ft.
Swell direction: 325°
Swell height: 4-6 ft.

Science/Technology Log 

Today we did a fishing trawl off the coast of Oregon. First, the scientists used multiple acoustic frequencies of sound waves.  After analyzing the sonar data, the scientists felt confident that they would get a good sampling of hake. The chief scientist called the bridge to break our transect line (the planned east/west course) and requested that we trawl for fish.

Here is an acoustic image (2 frequencies) as seen on the scientist’s screen. The bottom wavy line is the seafloor, and the colored sections above are organisms located in the water column.

Here is an acoustic image (2 frequencies) as seen on the scientist’s screen. The bottom wavy line is the seafloor, and the colored sections above are organisms located in the water column.

The NOAA Corps officers directed operations from the trawl house while crew members worked to lower the net to the target depth.  The fishing trawl collected specimens for approximately 20 minutes. After that time, the crew members haul in the net. The scientists continue to record data on the trawl house.

The trawl net sits on the deck of the Miller Freeman and is ready to be weighed and measured.

The trawl net sits on the deck of the Miller Freeman and is ready to be weighed and measured.

Today’s total catch fit into 2 baskets, a “basket” is about the size of your laundry basket at home, approximately 25-35 kilos. Included in the sample were some very interesting fish:

  • Viper fish
  • Ctenophores or comb jellies
  • Larval stage Dover sole, lives at the sea bottom
  • Jelly fish, several varieties (*Note: Jelly fish are types of zooplankton, which means they are animals floating in the ocean.)
  • Hake, approx. 30 kilos

The scientists made quick work of weighing and identifying each species of fish and then began working with the hake. Each hake was individually measured for length and weighed.  The hake’s stomach and otolith were removed. These were carefully labeled and data imputed into the computer.  Scientists will later examine the contents of the stomach to determine what the hake are eating. The otolith (ear bone) goes through a process by which the ear bone is broken in half and then “burnt.” The burning procedure allows one to see the “age rings” much like how we age a tree with its rings.

Personal Log 

A view from the trawl house during a fishing trawl.

A view from the trawl house during a fishing trawl.

Everyone works so very hard to make the Hake Survey successful.  All hands on the ship do a specific job, from cook to engineer to captain of the ship.  It is evident that everyone takes their job seriously and is good at what they do. I feel very fortunate to be part of this very important scientific research project.



A viper fish

A viper fish

Did You Know? 
Bird facts: An albatross’ wing span can be 5 feet, which equals one very large sea bird. A shearwater is slimmer and smaller yet resembles an albatross.

Animals Seen Today 
Ctenophore, Jelly Fish, Dover sole, Hake, Humboldt squid, Fulmar, Albatross, Gull, and Shearwater.

Here is something interesting, a hake with two mouths discovered in the trawl net.

Here is something interesting, a hake with two mouths discovered in the trawl net.

A hake and its stomach contents, including krill, smaller hake and possibly an anchovy

A hake and its stomach contents, including krill, smaller hake and possibly an anchovy

Dover Sole, larval stage

Dover Sole, larval stage†

NOAA Oceanographer John Pohl and NOAA Fish Biologist Melanie Johnson discuss data about the fish collected.

NOAA Oceanographer John Pohl and NOAA Fish Biologist Melanie Johnson discuss data about the fish collected.

John Schneider, July 18-20, 2009

NOAA Teacher at Sea
John Schneider
Onboard NOAA Ship Fairweather 
July 7 – August 8, 2009 

Mission: Hydrographic Survey
Geographical Area: Kodiak, AK to Dutch Harbor, AK
Date: July 18-20, 2009

Shumagin Islands, in transit to Dutch Harbor

Weather Data from the Bridge 
Weather System:
(July 18th) Low system approaching from the South
(July 19th) Fog, gusty wind in the morning, clear afternoon, but getting windier; Wind: southwesterly at 4-6 kts; Sea State: 1-2 feet

Weather System:  Projected for the July 20-21 overnight
Barometer: falling rapidly (a warning sign of unsettled weather) Wind: sustained at 30-40 kts, gusting to 55 kts (This would qualify as a “gale”)
Sea State: Predicted wave height next 24-36 hrs – 18 feet!

Andy and lunch—a nice halibut!

Andy and lunch—a nice halibut!

Science and Technology Log 

On the 18th and 19th, the launches went out (including me on the 19th) to clean up some holidays and get more near-shore data.  When we got back on the 19th, we found out that a major low pressure system was building to the south and expected to be in our area within a day and a half.  A major low system can reach out a couple of hundred miles and the CO decided that we would leave the Shumagins about 18 hours earlier than originally planned.  I discussed this with him (he is remarkably approachable) and he reiterates to me what I had already believed: his responsibilities are in three priorities – 1. His crew.  2. His ship.  3. The mission. Our research in the Shumagins does not represent life-or-death, it represents the continuing quest for knowledge and the expansion of our understanding of the Earth.  I’m sure you’ve realized it already, but Captain Baird and his officers have earned my highest regard.

We are in the center of the radar screen and two other ships described below – with their courses projected from the boxes that represent them – are behind us. The green line is our track ahead.

We are in the center of the radar screen and two other ships described below – with their courses projected from the boxes that represent them – are behind us. The green line is our track ahead.

On board the Fairweather is a phenomenal array of electronics.  Our positioning equipment is able to determine our position with just a couple of meters and when we are on a course it can tell if the course error is as little as a decimeter! Operating in Alaska, where fog is a way of life, RADAR (Radio Direction And Ranging) is an absolute must, and we have redundant systems in the event one breaks down. Probably the coolest thing about the radar is the use of ARPA technology. ARPA (Automated Radar Plotting Aid) is a system that not only identifies other vessels on the water, but diagrams their projected course and speed vectors on the screen. It does this from as far as 64 miles away!

The filleted tail of the halibut and some crabs found in its stomach

The tail of the halibut and some crabs found in its stomach

By looking at the screen, you can see the lines of other ships relative to your own and navigate accordingly. Furthermore, the system includes ECDIS, which is an Electronic Chart Display and Information System that identifies other ships as to their name, size, destination, and cargo!  So when you see on the radar that you are in a situation where you will be passing near to another vessel, you can call them on the radio by name! This technology is essential, especially going through Unimak Pass.  Unimak Pass is about 15 miles wide and is a critical point in commercial shipping traffic between the Americas and Asia. As we were transiting Unimak Pass, We were passed by an 800 foot long container ship that was en route to Yokohama, Japan and going the other way was a 750 foot ship going to Panama.  This is a critical area due to what is called “Great Circle” navigation.  I’ll address this point when in Dutch Harbor next week.

Eat your hearts out!

Eat your hearts out!

Personal Log 

Last night, after the beach party, Andy Medina (who has been on board for almost 200 days this year) was fishing off the fantail and caught a nice halibut. The crew who hail from Alaska all have fishing permits and when the day is done, if we’re anchored they get to use their free time for fishing.  They even got a freezer to keep their filets in.  Earlier in the cruise, we actually had halibut tacos made with about the freshest Alaskan halibut you can find (less than 12 hours from catch to lunch!)  Of course, with me being a bio guy, I asked for two things: 1 – to keep and freeze the head (I For the last night of the leg before making port in Dutch Harbor  (home of the World’s Deadliest Catch boats) the stewards, Cathy Brandts, Joe Lefstein and Mike Smith really outdid themselves.  I sure hope you can read the menu board, but if you can’t, dinner was Grilled NY Strip Steak and Steamed Crab legs with Butter! 

We went through about 10 trays like this!!!

We went through about 10 trays like this!!!

After dinner, everybody secured as much equipment as possible in the labs, galley and cabins as possible in anticipation of the run ahead of the weather into Dutch Harbor.  We ran through the night and got to Unimak pass in the middle of the day on the 20th. About half way through the pass was an unusual announcement, “Attention on the Fairweather, there are a lot of whales feeding off to starboard!” It’s the only time whales were announced and it was worth the announcement.  For about 2 to 3 miles, we were surrounded by literally MILLIONS of seabirds and a score or more of whales.  Comments from everybody were that they had never seen anything like it. I kept thinking of the old Hitchcock film The Birds and the scenes in Moby Dick where Ahab says to “watch the birds.” We were all agog at the sight.

Fifteen minutes of this! Incredible!

Fifteen minutes of this! Incredible!

With the collective 200-300 years of at-sea experience, no one had ever seen anything like it. After 2.5 weeks that seems like 2.5 days, we approach Dutch Harbor and are secured to the pier by 1700 hours. Tonight we’ll head into town, but if not for the news in the next paragraph, this would be the worst time of the trip, however . . .

The Best news of the trip: I’ve requested and been approved to stay on board the Fairweather for the next leg! WOO-HOO!!!  It’s called FISHPAC and deals with integrating bottom characteristics to commercially viable fish populations!  I’m going to the Bering Sea!!!

Questions for You to Investigate 

  1. When did the Andrea Doria and Stockholm collide?  Where?  In what conditions?
  2. What was the D.E.W. Line in the Cold War?
  3. Why did the Japanese want bases in the Aleutians in WWII?
  4. Why did we pass a ship going from North America to Yokohama well over 1000 miles north of both ends of the trip?
  5. What are Great Circles?

Did You Know? 

That almost 10% of all commercial fishing catch in the United States comes through Unalaska and Dutch Harbor?

Approaching Dutch Harbor

Approaching Dutch Harbor

Brenton Burnett, June 29, 2006

NOAA Teacher at Sea
Brenton Burnett
Onboard NOAA Ship David Starr Jordan
June 26 – July 6, 2006

Mission: Shark Abundance Survey
Geographical Area: California Coast
Date: June 29, 2006

Weather Data from Bridge 
Visibility:  10 nautical miles (nm)
Wind direction:  306 degrees
Wind speed:  15 kts
Sea wave height: 1-2’
Swell wave height: 2-3’
Seawater temperature: 19.8 degrees C
Sea level pressure:  1017 mb
Cloud cover: Partly cloudy

The beaks of a variety of squids and a fisheye lens found in a blue shark’s stomach.

The beaks of a variety of squids and a fisheye lens found in a blue shark’s stomach.

Science and Technology Log 

While today’s catches were lighter than yesterday’s, there were some very interesting new sights to see. One blue shark that made it up on deck, threw up some of its stomach contents.  Out came the remains of a pelagic (open water) crab and a number of squid beaks. The largest of these beaks was three centimeters (just over an inch) in diameter and the smallest less than a half a centimeter. Blue sharks are perhaps the most widely distributed shark, living in all oceans except in the polar latitudes. As such, they are generalists and eat squid, fish, smaller sharks and even birds. Jacques Cousteau even filmed blues shepherding virtually invisible krill into balled clusters so they could swim through the ball to feast. While setting the afternoon line, I saw a curved tip dorsal fin break the surface off the starboard bow. Then it disappeared under a wave.  Moments later as we caught up to it, a large disc of a fish could be seen below the fin—a mola!!  Molas are the largest bony fish though they are not the largest of all fishes. That honor belongs to the docile plankton-eating whale shark. Molas can reach a length over 4 m (13 feet), though the one we saw was closer to 2 m (6 feet).  Whale sharks, however, can grow to over 20 m (70 feet) long.

Bottlenose dolphins porpoising in front of the bow of the DAVID STARR JORDAN.

Bottlenose dolphins porpoising in front of the bow

Later, as we hauled the afternoon set, another mild surprise—a pelagic stingray was caught on our line! Once aboard, the highest priority was to disarm the poisonous spine projecting from the base of the stingray’s tail.  While Sean Suk, another Southwest Fisheries Science Center (SWFSC) researcher, held the ray down, Suzy Kohin was able to clip the spine disabling the ray, but not harming it. Rays and skates evolved flattened bodies as an adaptation as benthic, or bottom feeders. Rays and skates, or batoids as they are called collectively, have a mouth positioned on the bottoms of their bodies so they can best feed along the bottom of the ocean. Pelagic rays, as their name implies, live in the open ocean. So the pelagic ray has evolved a unique style of feeding. When approaching a school of fish, this ray will turn upside down and curl its wings above it forming a funnel.  This funnel shape directs the fish right to its mouth.

In the evening, after our work was done for the day, a few of us were on the stern deck when a school of dolphins approached. Soon they surrounded the ship and a group of six or seven stayed with us porpoising at our bow for close to thirty minutes!  “Porpoising” is the arched jumping above the water as dolphins swim. This behavior allows these mammals to breathe while maintaining their pace.  Porpoising should not be confused with breaching which is a more vertical jump from the water. Breaching behavior has been observed in a number of whale species, but also in some sharks.  The two shark species best known for breaching happen to be the two species we are most interested in on this cruise—makos and threshers.  Scientists are not certain why whales breach, nor are they entirely certain why sharks breach.  At least a partial answer may be that they are making an attack on prey.  Many sharks, not just blues, are known to eat sea birds, and makos, specifically, have been seen jumping from the water in attempts to attack floating sea birds. White sharks, the larger cousins of makos, are known to breach but in False Bay near Dyer Island off South Africa, this behavior could even be described as common.  The unique seafloor topography there forces the southern fur seals to repeatedly swim from surface to seafloor as they make their way to the island (if they didn’t they would be eaten by the sharks outright). Researchers have discovered that as the great whites pursue the seals from the depths their momentum takes them up and fully out of the water in spectacular breaches.

Personal Log 

Every day on board brings something new to this mountain man.  On deck, when critters aren’t appearing on board or in the sea, there are always science folks to answer questions. Of course, that is when they aren’t watching World Cup soccer via the satellite TV.  ‘Til, tomorrow…