acoustics – Page 2 – NOAA Teacher at Sea Blog

July 26, 2018July 26, 2018

Michelle Greene: Visual Sighting Team, July 23, 2018

NOAA Teacher at Sea

Michelle Greene

Aboard NOAA Ship Gordon Gunter

July 19 – August 3, 2018

Mission: Cetacean Survey

Geographic Area: Northeast U.S. Atlantic Coast

Date: July 22-23, 2018

Latitude: 40° 35.213″ N

Longitude: 66° 6.692″ W

Sea Surface Temperature: 23.4° C (74.1° F)

Knots: 7.85 knots

Science and Technology Blog:

The visual sighting team started early this morning at 6:00 am and had rotating shifts of 30 minutes each until 7:00 pm. The different shifts included watching with regular binoculars on the port and starboard sides, watching with the big eyes on the port and starboard sides, and being the data recorder for sightings. I had the opportunity to shadow scientists in each of these positions throughout the first day and actually performed the duties on the second day.

Members of the Cetacean Survey Visual Team on Lookout

One of the important jobs the data recorder has is to input the environmental conditions at a certain point in time. The first measurement to input is the percent of cloud cover which is just a number from 0 to 100. Then the glare magnitude is determined on an ordinal scale from 0 to 4 with a value of zero meaning none and a value of four meaning severe. After determining the glare magnitude, the percent of glare cover is determined. Since the two sets of big eyes cover from 90 degrees left of the bow to 90 degrees right of the bow, the glare covering this spaced is what is determined. The data recorder also has to determine the degree angle and height of the ocean swell. Swell is not the wind waves generated by local weather. It is the wind waves that are generated by distant weather systems. Then the Beaufort scale is used to determine the amount of wind on the ocean. The scale was developed by Sir Francis Beaufort of the United Kingdom Royal Navy in 1805. The scale ranges from 0-12. A zero score means the surface is smooth and mirror like, while a score of 12 means there are hurricane force winds. Rain or fog is also determined by the data recorder. Finally, the data recorder has to determine a subjective condition of the weather overall. This is on an ordinal scale from 1 to 4 with 1 being poor and 4 being excellent.

When a marine animal is sighted by one of the observers, the data recorder has to input several measurements about the event. The bearing of the location of the animal has to be determined using the big eyes. Also, the big eyes have a scale in the lens called reticles that determines distance from the ship to the animal. A conversion scale can then be used to determine how far away the animal is in meters or nautical miles. The number of animals sighted, including any calves that are in the group, has to be given. The group’s swim direction has to be determined based on bearing from the ship. If possible, the species of the group has to be given. Since the objective of this survey is to find the occurrence of Mesoplodons in the North Atlantic Ocean, determining the species is very important. Also the observer has to give the initial cue as to what determined the identification of the species. Several different cues are available such as the body of the animal, the blow of a whale or dolphin, or the splash.

The software used to input the occurrence of a marine mammal automatically inputs the GPS of a sighting. The initial route for this survey is a zig zag pattern out of Rhode Island towards Georges Bank. There are several canyons with very deep waters (over 1,000 meters) which is where the Mesoplodons make foraging dives to get food. Instead of making a straight line through the canyons and only making one pass through the area, using zig zag routes gives the survey a better chance of locating Mesoplodons. The chief scientist uses the information from sightings to track a path for the ship to take the next day. Sometimes the acoustics team hears possible Mesoplodons. If the acoustics team can find a convergence of the area of an animal, they will tell the ship to go at a slower rate or turn.

The map here shows the sightings of Mesoplodons from the beginning of our journey and the zig zag pattern taken by the chief scientist. The first day of our journey, a storm was coming up the East Coast. The Gordon Gunter‘s Commanding Officer (CO) determined that we could run from the storm by going east in a straight line direction instead of doing the zig zag motion. The CO was correct, because we did not have bad weather. The ocean had a lot of high swells which made the boat rock tremendously at times but no rain.

GU18-03_Map_24July2018_wLegend — A map of the daily route of the Gordon Gunter based on sightings.

Personal Log

I have found my favorite place to be on the visual sighting team…being the data recorder. Statistics is my passion, and being the data recorder puts me in the middle of the action getting mass amounts of data. It also helps that the data recorder sits in a high chair and can see a wide area of the ocean. The scientists have been very helpful in finding me a milk crate, because that chair is so high I cannot get onto it without the milk crate. Being the data recorder can be intense sometimes, because multiple sightings can be made at the same time. In any free time I have, I will fill in as the data recorder. It is lots of fun!

One thing that was a little intimidating to me at first was the intercom system. I would hear things like, “Fly Bridge Bridge.” Then the data recorder would say “Bridge Fly Bridge.” I had no clue of what they were talking about. Then all of a sudden it made sense to me. In “Fly Bridge Bridge,” someone from the Bridge is calling up to us on the Fly Bridge. The Bridge has a question or wants to tell the people on the Fly Bridge something. Since I figured it out, I am ready to go.

I have learned so much on this cruise in the short time I have been aboard the Gordon Gunter. My head is exploding with the numbers of lessons that I can incorporate into my statistics classes. I have also talked with the acousticians, Jenny, Joy, Emily, and Anna Maria, and have come up with lessons that I can use with my algebra and calculus classes as well. The scientists have been very generous in sharing their knowledge with a science newbie. Being a math teacher, I want to be able to expose my students to all kinds of content that do not deal with just the boring math class. Being a Teacher at Sea has opened up a whole new experience for me and my students.

We have an interesting participant in our cruise that I was not expecting but was happy to meet…a seabird observer. Before this cruise I did not know there were birds that pretty much lived on the surface of the ocean. These birds have been flying around the ship which is about 100 nautical miles from shore. The seabird observer documents all sightings of seabirds and takes pictures to include in his documentation.

Did You Know?

Reticles are the way a pair of binoculars helps observers to determine the distance to an animal; however, the conversion from reticles to distance is not an instantaneous solution. Based on the height of a pair of binoculars on the ship, reticles can mean different distances. A conversion chart must be used to determine actual distance.

Check out this article on how to estimate distance to an object with reticles in a pair of binoculars:

Using reticle binoculars to estimate range

Animals Seen

Sperm whales (Physeter macrocephalus)
Fin whales (Balaenoptera physalus)
Cuvier’s beaked whale (Ziphius cavirostris)
Risso’s dolphins (Grampus griseus)
Bottlenose dolphins (Tursiops truncatus)
Common dolphin (Delphinus delphis)
Great shearwater bird (Puffinus gravis)
Cory’s shearwater bird (Calonectris borealis)
Wilson’s storm petrel bird (Oceanites oceanicus)
Leach’s storm petrel bird (Oceanodroma leucorhoa)
White-faced storm petrel bird (Pelagodroma marina)
Red-billed tropicbird (Phaethon aethereus)

Vocabulary

acoustician – someone whose work deals with the properties of sound
bearing – the direction from your location to an object in the distance starting at 0° which is located at absolute north. For example, if an animal is spotted at 90°, then it is due east of your location.
blow of a whale – the exhalation of the breath of a whale that usually looks like a spray of water and is an identifying feature of different species of whales
bow of a ship – the point of the ship that is most forward as the ship is sailing (also known as the front of the ship)
cloud cover – the portion of the sky that is covered with clouds
foraging dive – a type of deep dive where a whale searches for food on the ocean floor
glare – the light reflected from the sun off of the ocean
nautical mile – a measurement for determining distance on the ocean which is approximately 2025 yards (or 1.15 miles) or 1852 meters
port side of a ship – when looking forward toward the bow of the ship, the left side of the ship is port
starboard side of a ship – when looking forward toward the bow of the ship, the right side is starboard

July 23, 2018July 23, 2018

Michelle Greene: Setting Sail on the Gordon Gunter, July 20, 2018

NOAA Teacher at Sea

Michelle Greene

Aboard NOAA Ship Gordon Gunter

July 20-August 3, 2018

Mission: Cetacean Survey

Geographic Area of Cruise: Northeast U.S. Atlantic Coast

Date: July 20, 2018

Weather Data from the Bridge

Latitude: 41° 31.838′ N

Longitude: 71° 19.018′ W

Air Temperature: 26.7° C (80° F)

Conditions: Sunny

Science and Technology Log

Beaked whales are elusive creatures that roam all of the world’s oceans. The purpose of this cetacean cruise is to find the occurrence and distribution of beaked whales in the northeast Atlantic off the coast of Rhode Island and Massachusetts. The beaked whale is a toothed whale from the family Ziphiidae. Several types of beaked whales have been spotted in this region including the True’s beaked whale (Mesoplodon mirus) and the Cuvier’s beaked whale (Ziphius cavirostris).

To find the occurrence of beaked whales, the scientists are using several different methods. The first method is a visual sighting of the animals. High-powered binoculars, affectionately termed “big eyes” can see animals from several nautical miles away. Then regular binoculars are used to scan the areas closer to the ship. The second method scientists are using is by passive acoustics. Acousticians are using two different types of listening devices to try to hear the whales. The first device is called a linear array. In this device, four hydrophones are attached to a tube in a linear pattern. The array is then towed in the water behind the ship, and acousticians can hear the whales when they communicate. The acousticians can then determine how far the whale(s) is(are) from the device. However, with this type of array, it is difficult to calculate how deep the whale is in the water.

In an effort to improve detection of the depth of a beaked whale, a new array has been designed. This tetrahedral array is designed so that the four hydrophones are placed in a way that is not linear two-dimensional space but in a more three dimensional space, so scientists can detect not only the distance of a whale but the depth. We will be testing a new prototype of this array during this cruise.

Personal Log

Arriving the day before the Gordon Gunter sailed allowed me to see some pretty interesting things. I got to help two of the scientists put up the “big eyes.” These binoculars are really heavy but can see very far away. On the day we sailed, we were able to zero the binoculars which means we set the heading on the binoculars to zero with the ship’s bow based on a landmark very far away. We could not zero them the day before, because there was not a landmark far enough away to get an accurate reading.

The Gordon Gunter is one of the larger ships in the NOAA fleet according to several of the scientists who have been on many cruises. It took me a while to figure out where all of the doors go and how they open. I did not realize how hard it was to open some of the doors. According to the XO, the doors are hard to open because of the pressure vacuum that exists in the house of the ship. There is not really a reason for the vacuum to exist. It is just the nature of the ship.

Life on board the Gordon Gunter has been very interesting for the first day. Before leaving port, we had a fleet inspection. We had to do all of our emergency drills. Safety is very important on a ship. We had to do a fire emergency drill where everyone had to meet at a muster station and be accounted for by one of the NOAA officers. Then we had to do an abandon ship drill. Then once we got sailing a short time, we had to do a man over board drill.

Donning the immersion suit in case of an abandon ship order was not a thrill for me but was comical in retrospect. I am only 4’ll”, and the immersion suit I was given is made for someone who is over six feet tall. When I tried on the suit, I had two feet of immersion suit left at the bottom. When the NOAA officer came to inspect, he said I definitely needed a smaller suit.

One of the best features of my cruise so far has definitely got to be the galley. The Gordon Gunter has the best cook in Miss Margaret. She is the best and makes awesome food. She has made cream cheese from scratch. She makes the best smoothies. I can only imagine what we are going to be getting for the rest of the cruise.

Did You Know?

All marine mammals, including the beaked whales, are protected under the Marine Mammal Protection Act.

Check out this website on what the law states and what it protects:

https://www.fisheries.noaa.gov/topic/laws-policies#marine-mammal-protection-act

July 11, 2018July 11, 2018

Joan Shea-Rogers: Do You Hear What They Hear, July 8, 2018

NOAA Teacher at Sea

Joan Shea-Rogers

Aboard NOAA Ship Oscar Dyson

July 1-22, 2018

Mission: Walleye Pollock Acoustic Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 8, 2018

Weather Data from the Bridge

Latitude: 53º N

Longitude: 166ºW

Sea Wave Height: 1.5 feet

Wind Speed: 25 Knots

Wind Direction: SW

Visibility: 15 miles

Air Temperature: 52ºF

Water Temperature: 46º F

Barometric Pressure: 1010.61mb

Sky: Overcast

Science and Technology Log

What kinds of fish live in the Bering Sea? How many pollock are in the Bering Sea? Where are the pollock in the Bering Sea? How big are the pollock in the Bering Sea?

Those are just a few of the questions that the fisheries biologists on NOAA Ship Oscar Dyson work to answer during each voyage. In my last blog, I talked about the need to manage the pollock fishery in order to protect this important ocean resource because it provides food for people all over the world. It is important, then, to be able to answer the above questions, in order to make sure that this food source is available each year.

How do they do it? There are two main sources of information used in the Acoustics-Trawl (or Echo Integration Trawl) survey to determine the abundance and distribution of pollock in a targeted area of the Bering Sea. One is acoustics data, and the other is biological-trawl data.

Acoustics:

Acoustic data is continuously collected along a series of parallel transects with a Simrad EK60 scientific echo integration system incorporating five centerboard-mounted transducers (18-, 38-, 70-, 120-, and 200- kHz). In other words: There are 5 sound wave producers (transducers) attached to the bottom of the ship, each one emitting sound waves at different frequencies. This allows scientists to look at different organisms in the water column. Different types of organisms reflect different amounts of energy at different frequencies. The amount of acoustic energy reflected by an individual animal is called the target strength, and is related to the size and anatomy of the species. For example, a fish with a swimbladder (like pollock) reflects more energy than a fish without a swimbladder because its properties are very different from the surrounding water. Some ocean dwelling organisms don’t have swim bladders. Flatfish stay on the bottom so they don’t need the buoyancy. Floating organisms like jellyfish don’t have them. These organisms will look differently than pollock on an echogram because they have a smaller target strength.

Transducers convert mechanical waves (sound waves) into an electrical signal and vice versa (like both a loudspeaker and a microphone combined). They contain piezoelectric materials sensitive to electricity and pressure: if a voltage is applied to them, they make a pressure or sound wave (transmit), and when a sound wave passes over them, it produces a voltage (receive). When a sound wave (echo from a fish) is received, electoral signal is sent to a computer, which displays the signals as pixels of varying colors as the ship moves along (depth changes up and down on the left of the image, and time and location changes along the bottom of the image). This datum is used to estimate the number and type of fish in the water column, and to determine where the ship should fish next.

The size and colors on the images (called echograms) represent the backscatter at different depths and is related to the density of fish and their target strength. But, since they are dots on a screen, specific identification is not possible. The scientists assume certain strong signals are pollock based on the information they have but, those dots could be other fish. To determine what kind of fish are in the water column at this location, how many are there, and how big they are, other data must be obtained. Biological Trawl Data provides that additional information. More about that in my next blog post……I bet you can’t wait!

Personal Log

The Calm Before the Storm:

So far my trip has been smooth sailing, literally. As NOAA Ship Oscar Dyson sails across the Bering Sea there is a bit of rocking the ship experiences at all times. This is easy enough for one to get used to and sometimes it even becomes comforting, like being rocked to sleep as a child. You adjust to the motion. Over the past couple of days I have been hearing talk of a storm coming our way. On a ship, there are many preparations that occur in order to get ready for a storm. Many items are always secured, such as shelves that have a wall in front so that things don’t fall off. There are “handle bars” in showers and next to toilets (think about that). Along hallways and stairways there are handrails on each side. Mini refrigerators in staterooms are bolted to walls. In fact most things are bolted to walls or stored in containers that are bolted to the wall. In the mess hall (dining room) condiments on tables are in a box so they can’t slide off.

Why do you think this coffee mug is shaped like this (wider at the bottom than the top)?

Ans. The wider bottom of the mug above prevents it from sliding as the ship rocks.

Our bulletin board reminds us to secure for bad weather. This morning, I put small items in drawers, stowed books on shelves and packed my equipment (phone, laptop, camera, chargers and small items in a backpack that can be safely secured in my locker (the “closet” in my stateroom).

In talking to my shipmates with at sea experience, I am getting lots of helpful hints about storm preparations and strategies to use during the storm. Here are some of those suggestions:

*always hold on to railings with both hands when walking or going up steps. At all other times, remember to keep one hand for you (to do whatever you are doing) and one hand for the ship (to hold on).

*keep something in your stomach at all times, even if you are not feeling well

*eat saltines

*drink lots of water

*when sleeping in your bunk, place pillows between you and the edge so as not to roll off (I will definitely follow this one, as I am on the top bunk) It also depends upon which direction the ship is rolling. Pillows may need to be put between your head and the wall to prevent head bumps

*go to the lower parts of the ship because the top part will sway more with the waves

I also have been wearing patches to prevent seasickness. Hopefully they will continue to help. Only time will tell how we weather the storm (pun intended). Let’s hope it moves through quickly.

July 9, 2018

Lee Teevan: Getting Schooled in the Nature of Science, July 8, 2018

NOAA Teacher at Sea

Lee Teevan

Aboard NOAA Ship Oscar Dyson

July 1 – 21, 2018

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: East Bering Sea

Date: 8 July 2018

This is a view approaching Dutch Harbor, AK.

Weather Data from the Bridge

Latitude: 66 N

Longitude: 166 W

Sea Wave Height: 2ft

Wind Speed: 25 knots

Wind Direction: SW

Visibility: 15 miles

Air Temperature: 52°F

Barometric Pressure: 1010.61 mb

Sky: overcast

Science and Technology Log

Although July has just begun, teachers are already anticipating the first day of school. Like every science teacher, we launch our classes with the “Nature of Science” or the “Scientific Investigation.” Unlike past years, I plan on contextualizing these topics by showing my students the “scientific investigation in action” by describing how scientists aboard the Oscar Dyson studying eastern Bering Sea pollock populations apply the scientific method in their research.

To better understand how scientists “do science,” I had a conversation with Dr. Patrick Ressler, our Chief Scientist, about this topic. Dr. Ressler has been involved with the Pollock Acoustic Trawl Survey for many years and stresses that this ongoing research is a way to monitor change over time with pollock populations and to set quotas for commercial fisheries. He shared his ideas about science and how it is a way to understand natural phenomena through testing. In biological research, however, it is harder to assess the outcomes because of the potential effects of outside factors. That is why scientists refine their experiments to get “closer to the truth.” Even being “wrong” about some ideas is beneficial because it facilitates opportunities to learn more. Scientists give testable ideas, or hypotheses, the chance to be wrong through repeated trials.

It was a circuitous path that Dr. Ressler took to become a scientist. He studied environmental science and creative writing as an undergraduate, but after a semester abroad learning nautical science, he decided to study oceanography as a graduate student. For his graduate studies, Dr. Ressler focused on acoustics and has worked on Pacific hake populations along the west coast of the U.S. For the past 16 years, he has worked with NOAA as a Chief Scientist whose responsibilities include being a point of contact between the ship’s commanding officer and the management supervisor on land. He has supported NOAA’s Teacher at Sea program because he feels that a good science teacher can better cultivate and inspire future scientists.

Screen with Acoustics Data — The screen displaying acoustics data is always monitored.

The scientists on the Oscar Dyson have varied academic specialties, yet they are collaborating on the Pollock Acoustic Trawl Survey by contributing their expertise. Dr. Ressler and Dr. Chris Bassett have been monitoring the acoustics on this expedition. The acoustic system was most patiently explained to Joan and me by Dr. Bassett.

Dr. Chris Bassett, Ocean Acoustics Engineer

On the Oscar Dyson, there are 5 transducers producing vibrations on the drop keel of the boat. Cables are attached that can lower this drop keel to 9.2 meters below so that storms will not interfere with the acoustics. These cables connect the drop keel to the five boxes in the survey room. Voltage signals are sent to the transceiver, which in turn creates a pressure wave. When the signal is sent into the water, some sound bounces back. The pressure waves reflected back to the transducer are converted to an electrical signal and recorded by the computer. For the sound wave to scatter off something, it must have a density or sound speed different from that of the surrounding water. The larger the differences in the properties of the animals from the surrounding water, the more sound will generally be reflected by an animal. As a result, animals with ‘swim bladders’ (an organ inside their body containing air) will generally scatter more sound than animals without them.

When one of the transducers sends out a wave, the wave spreads out as it moves from the ship and it may encounter fish. To assess the number of fish present, the total amount of acoustic energy, the volume of water, the range, and the echo expected from a single fish must be measured or estimated.

The acoustics translate into an ongoing screen display which is observed by both Dr. Ressler and Dr. Bassett in the acoustics lab. The data displayed allows the scientists to decide whether a net sample is needed.

These scientists adhere to the scientific method so that they can make strong conclusions about their data. The acoustics portion is but one part of this ongoing research. The trawls, after which we measure the length and mass of each fish, is a means of supporting the data from the acoustics portion. There are also cameras attached to the net so that the scientists can verify the type and abundances of fish species at each sampling transect. By corroborating findings in acoustics with the data from the trawls, these scientists can use their combined data to give greater insight on pollock populations and abundances.

Personal Reflection

I am in awe of people who do what they love for a career. The scientists with whom I spoke convey their passion for their areas of expertise and are willing to share their knowledge. These scientists have made me aware of outside resources so that I can learn more about the topic. Collaboration is evident among these scientists as each works to illuminate an aspect of the pollock population. Together, their work sheds light on pollock dynamics.

Marine Careers

Sandi Neidetcher, a research fishery biologist at the NOAA’s Alaska Fishery Wildlife Center, holds a bag of pollock ovaries.

Scientists aboard the Oscar Dyson participate in the Pollock Acoustic Trawl Survey research as well as projects of their own. Sandi Neidetcher, a research fishery biologist at the NOAA’s Alaska Fishery Wildlife Center, is investigating the reproductive biology of pollock and cod. According to Sandi, the reproductive biology of pollock is important for assessing the stock. By carrying out data collection of pollock length and otolith analysis, scientists can determine whether 50% of the stock is mature. For pollock, using the otolith analysis is a good indicator of age. Otoliths are made of calcium carbonate and are found in the fish’s inner ear and otoliths have annual growth rings, which allows for scientists to accurately assign their ages. Since pollock is a commercial fish, it’s important to know how many of the fish are capable of reproducing and using this data, set quotas commercial fishing. Another facet in researching pollock populations is determining where and when pollock spawn as well as the frequency of spawning. Sandi has been studying pollock, in addition to other commercially caught species, for many years as a commercial fishery observer. Currently, she is sampling pollock ovary tissue to determine fecundity, or fertility, of the population for stock assessment.

Sandi advises high school students who think they’d enjoy this type of career to get a college degree in biology. She also encourages them to network and apply for internships. Effusive when recounting her career in research, Sandi is equally enthusiastic discussing her horse and misunderstood dog.

Did you know?

Otoliths aid fish like pollock in balance and acceleration.

Something to think about….

What are some factors that might affect the growth of otoliths?

August 6, 2017August 6, 2017

Brad Rhew: The Sounds of the Sea, July 31, 2017

NOAA Teacher at Sea

Brad Rhew

Aboard NOAA Ship Bell M. Shimada

July 23 – August 7, 2017

Mission: Hake Fish Survey

Geographic Area of Cruise: Northwest Pacific Ocean, off of the coast of Oregon

Date: July 31, 2017

Weather Data from the Bridge

Latitude: 44 49.160 N
Longitude 124 26.512

Temperature: 59^oF
Sunny
No precipitation
Winds at 25.45 knots
Waves at 4-5ft

Science and Technology Log

TAS Rhew 7-31 acoustics lab2 — Inside the acoustics lab

The scientists on the Hake survey project are constantly trying to find new methods to collect data on the fish. One method used is acoustics. Scientists Larry Hufnagle and Dezhang Chu are leading this project on the Shimada. They are using acoustics at a frequency of 38 kHz to detect Pacific Hake. Density differences between air in the swimbladder, fish tissue, and the surrounding water allows scientists to detect fish acoustically.

The purpose of the swim bladder in a fish is to help with the fish’s buoyancy. Fish can regulate the amount of gas in the swim bladder to help them stay at a certain depth in the ocean. This in return decreases the amount of energy they use swimming.

TAS Rhew 7-31 echosounder — The screen shows the data collected by the echosounder at different frequency levels.

Larry and Chu are looking at the acoustic returns (echoes) from 3 frequencies and determining which are Hake. When the echosounder receives echoes from fish, the data is collected and visually displayed. The scientists can see the intensity and patterns of the echosounder return and determine if Hake are present.

The scientists survey from sunrise to sunset looking at the intensity of the return and appearances of schools of fish to make the decisions if this is an area to fish.

TAS Rhew 7-31 scientists Larry and Chu — Scientists Larry Hufnagle (left) and Dezhang Chu (right) monitor the nets and echosounder while fishing for hake.

The ultimate goal is to use this data collected from the echosounder to determine the fish biomass. The biomass determined by the survey is used by stock assessment scientist and managers to manage the fish stock.

Personal Log

Everyday aboard the Shimada is a different experience. It has been amazing to be able to go between the different research labs to learn about how each group of scientists’ projects are contributing to our knowing more about Hake and marine ecosystems. My favorite part so far has been helping with the sampling of Hake. Some people might find dissecting fish after fish to determine length, sex, age, and maturity to be too much. However, this gives me an even better understanding and respect for what scientists do on a daily basis so we can have a better understanding of the world around us. We have also caught other fascinating organisms that has helped me explore other marine species and learn even more about their role in the ocean.

Even though the wind is a little strong and the temperatures are a little chilly for my southern body I wouldn’t trade this experience for anything…especially these amazing sunsets…

TAS Rhew 7-31 sunset — View of sunset over the Pacific Ocean from NOAA Ship Bell M. Shimada

Did You Know?

Before every fishing operation on the boat we must first do a marine mammal watch. Scientists and other crew members go up to the bridge of the boat to see if any mammals (whales, seals, dolphins) are present near the boat. This is to help prevent these animals from being harmed as we collect fish as well as making sure we are not running a risk of these mammals getting caught in the fishing nets.

Fascinating Catch of the Day!

Today’s fun catch in the net was a Brown Catshark! These creatures are normally found in the deeper parts of the Pacific Ocean. They are typically a darker brown color with their eyes on the side of their head. Their skin is very soft and flabby which can easily lead to them being harmed. They have two dorsal fins and their nostrils and mouth on the underside of their body. One of the sharks we caught was just recently pregnant.

Two brown catsharks

Catsharks have two dorsal fins (on their backs)

Catsharks’ nostrils and mouths are on the undersides of their bodies

Catshark egg sacks

Notice to yellow curly substance coming out of the shark? That is from the egg sac. Sharks only produce one egg sac at a time. It normally takes up to a full year before a baby shark to form!