Susy Ellison, So You Want to be a Hydrographer? November 5, 2013

NOAA Teacher at Sea
Susy Ellison
Aboard NOAA Ship Rainier
September 9 – 26, 2013

 

Mission:  Hydrographic Survey
Geographic Area:  Carbondale, CO
Date:  November 5, 2013 

Weather:  You can go to NOAA’s Shiptracker (http://shiptracker.noaa.gov/) to see where the Rainier is and what weather conditions they are experiencing while I am back at school in Glenwood Springs, CO.
GPS Reading: 39o 24,13146 N  107o 12.6711 W
Temp:  -8C
Wind Speed: 0
Barometer: 1026.00 mb
Visibility:  Clear 

Science and Technology Log

How do you become a hydrographer?  After spending 2 ½ weeks aboard the Rainier as a Teacher at Sea, I found that this question had as many answers as the ship had hydrographers.  In fact, if you take time to concatenate the data (obviously, I have become fond of my newest vocabulary word!), you will learn that being a hydrographer is incredibly multi-faceted and is a confluence of ocean-, cartographic-, and computer-based sciences, with some outdoor skills thrown in for good measure. 

Cdr Rick Brennan and some of the hydrographers of the future in Cold Bay, Alaska
Cdr Rick Brennan and some of the hydrographers of the future in Cold Bay, Alaska

The Rainier’s CO, Commander Rick Brennan, finished college with a degree in Civil Engineering.  In 1991, his senior year, he discovered NOAA when a professor suggested he check out the NOAA Corps during a recruiter’s visit to campus. He started as a NOAA Corps member in 1992 and has been involved in hydrographic survey work ever since.  His studies in the NOAA Corps training included coursework on ships, radar, and navigation, and led to his appointment as Commanding Officer (CO) of the NOAA Ship Rude (http://www.moc.noaa.gov/Decomm Ships/ru-index.html). This ship was NOAA’s smallest hydrography vessel at only 90’ long. 

Commander Brennan has seen many changes in hydrography during his career.  First and foremost, has been its evolution as an academic discipline.  The University of New Hampshire, based in Durham, NH, founded the Center for Coastal and Ocean Mapping in 1999.  Their Joint Hydrographic Center was created through a partnership between the University and NOAA.  (http://ccom.unh.edu/about-ccomjhc, http://www.eos.sr.unh.edu/) Prior to this, hydrography was part of more general courses in oceanography.  Now, you can get a Master’s Degree in Hydrography.

The last 20+ years have also seen significant changes in hydrographic technology, especially in the tools used to map the ocean floor.  Prior to 1994, hydrographic vessels were outfitted with single beam sonar, instead of the multi-beam sonar that is today’s standard.  The single beam only provided bathymetric data at a single position on the seafloor directly below the vessel, while multi-beam sonar can give us high resolution information about the seafloor across a swath of the seafloor stretching several hundred meters to either side of the vessel.  The Rainier, as NOAA’s premier hydrography vessel, was fully outfitted with multi-beam sonar by 1998. Other technological advances have included significant changes in information processing, from the days of paper tape and punch card programming, to the development of  hydrography-specific data analysis programs such as CARIS. 

While data collection capabilities have changed exponentially over the past 20 years, CDR Brennan noted changes in how that data is used.  NOAA has set the industry standard worldwide for collecting hydrographic data.  Departments within NOAA are able to use that data to more than make charts. Fisheries biologists can use the detailed seafloor information in their assessments of ecosystem health and the availability of suitable prey species for all parts of the complex ocean-based food web. Shorelines are dynamic; charting plays a role in establishing baseline data in a changing world. Brennan foresees a future where navigators will view charts using a variety of platforms besides merely lines on paper; this will take educating mariners in how to utilize some of the new electronic tools that are available.

Brennan reflected that, while there have been significant advances in the field of hydrography, there is still much work to do.  NOAA publishes an annual review of its hydrographic survey goals (http://www.nauticalcharts.noaa.gov/hsd/NHSP.htm) .  While this might not sound like the most scintillating of reads, it’s a fascinating look at the enormity of the concept of charting our coastline.  Depending on how you view coastline—is it a smoothed-out line of the coast, does it include all the ins and outs and bays, or does it include all the United States’ navigable coastline extending out 200 nautical miles—one thing is certain, there’s a lot of it.  In Alaska, alone, NOAA has identified 324,465 square nautical miles as Navigationally Significant.  The identified total for all of the United States, including the Caribbean, is 511, 051 square nautical miles.  Alaska is big!  The crew of the Rainier will have plenty of work!

Chief Surveyor Jim Jacobsen at work in the computer lab
Chief Survey Technician Jim Jacobson at work in the computer lab

Chief Survey Technician Jim Jacobson’s favorite area to survey is Southeast Alaska with its varied topography, underwater features, and interesting ports.  He should know, since he’s been a member of the Rainier’s survey crew since 1990.  Jim graduated from the University of Washington with a degree in Oceanography—at that time there were no hydrography-specific programs. When he began, a large part of the training consisted of good old, OJT—on the job training, learning new skills as new equipment and techniques became available.  Needless to say, there have been more than a few changes over the past 20+ years.

Jim began his career before GPS was a part of hydrographic survey.  Setting benchmarks to establish sea levels was done using transits and theodolites, triangulating from known points on land to establish location and elevation on shore.  Information was transmitted using microwave towers that were erected on site.  Fast forward to 2013, where GPS is part of everyone’s vocabulary and the ability to know ‘exactly’ where you are is often in the palm of your hand.  The Rainier’s tide gauge stations are set using GPS units that can identify location and elevation to within centimeters.

He also began his career using single beam sonar, instead of today’s multi-beam.  While single beam doesn’t have the pinpoint accuracy that multi-beam sonar might offer, there were a few advantages.  It was a faster way to collect data, since you weren’t collecting as much information with each ‘ping’.  Thus, you could complete more ‘sheets’ (an identified area for mapping) during your time at sea.

Hydrographic survey techniques have changed over time.
Hydrographic survey techniques have changed over time.
http://www.nauticalcharts.noaa.gov/mcd/learnnc_surveytechniques.html

There have been incredible advances in data analysis since Jim started on the Rainier.  Data collected each day has become more complex, requiring more hours of ‘cleaning’ to remove extraneous pings and information.  Hydrographers use increasingly complex computer software to produce charts, often spending up to 5 hours to process one hour’s data.

What’s next?  Jim imagines a future with underwater mapping done by ROVs, remotely operated vehicles, cruising the seafloor to send back terabytes of information.  ROVs are already used in a variety of information-gathering capacities, sending back high-quality video of seafloor conditions, information on water chemistry, or video of marine life from far below the surface.

Here's what hasn't changed--hydrographers work in all sorts of weather and ocean conditions!
Here’s what hasn’t changed–hydrographers work in all sorts of weather and ocean conditions!

Christi Reiser didn’t start out planning to be a hydrographer.  She has, perhaps, the most diverse resume of any of the survey team.  Christi is currently a college student, and will be receiving her BA in Geography from the University of Colorado, Denver at the end of this year.  Her hydrography career began in May, 2012 when she was hired as an intern on the Rainier, earning college credit while working for NOAA.

Christi Reiser
Christi Reiser

Since high school, Christi has earned an Associate’s Degree in Business, was employed as a saddle maker in Austria, and worked for an oil company as a mapping technician.  While all of those pathways gave her something to ponder, it was the GIS part of her mapping job that really ignited the fire that sent her back to college to pursue a degree in Geography with a focus on GIS and a minor in Environmental Science.  To further stoke that fire, Christi worked to design and pursue an internship experience that would allow her to ‘test drive’ a career combining GIS, hydrography, and life on the high seas.  Through a combination of motivation, Google-based searching, a diverse and applicable set of educational and experiential skills, and the courage to make some phone calls and take a few risks, Christi ended up on the Rainier, working as a paid intern. How cool is that?  She earns college credit, gains expertise working with challenging software and data acquisition programs and equipment, charts the uncharted ocean floor, and sees parts of Alaska that aren’t on the usual tourist’s destination list.  One of her projects during her first season on the Rainier was the creation of an online blog describing her work.  You can check it out at http://rainierinternship.blogspot.com/

Through her internship Christi has found that NOAA is one of the most education-oriented organizations she has worked for, constantly providing opportunities to learn new skills and information. She is excited to be working in a GIS-based field and considers it to be one that is ‘never-ending’, since only 4% of the sea floor has been mapped!  After graduation, her next step may be a Master’s Degree in Geography, to add more science research experience to her knowledge base.  After that?  Well, all I can say is that Christi plans to create a new job that “doesn’t even exist”.  Stay tuned.

So, the next time you’re talking to your guidance counselor about college plans, or wondering what you might want to be when and if you grow up, consider the field of hydrography.  Where else do you get to wear a life jacket to work?

Field Operations Officer  (FOO)Meghan McGovern  goes over the Plan of the Day
Field Operations Officer (FOO)Meghan McGovern goes over the Plan of the Day.  Where else do you get to wear a life jacket to work?

Personal Log

Now that I’ve been home a few weeks, it’s time to reflect on my Teacher at Sea experience.  I’ve been asked, more than once, “Did it meet my expectations”?  That’s an easy question to answer—the answer is “No, it exceeded my expectations!”  I came away from my time on the high seas with much more than just knowledge of the complexities of seafloor mapping.  As a firm believer in the concept that ‘everything is interesting’, it would be hard to point to any aspect of my trip that wasn’t something fun and interesting to learn!

The science of hydrography is amazing.  Just thinking about mapping something that you can’t actually see is an incredible concept.  I have always been fascinated with maps and the process of creating a map, but I look at those maps a little differently now, going beyond the story the map tells to thinking about how that map was made. The science of mapping has undergone many changes since those first sailors with their lead lines creating maps of harbors and shorelines.  In case you’re still wondering why hydrography and the Rainier’s mission is so important, check out this clip from a PBS special that aired in September–http://www.pbs.org/newshour/bb/climate-change/july-dec13/arctic_09-17.html

The teamwork, efficiency, and camaraderie on the ship were a common thread uniting each day’s activities.  Each crew member played a role in the success of the ship’s mapping mission. It took everyone from the engine room to the bridge to keep it all ‘shipshape’.  There was really no job too small—everything and everyone had a necessary role. I especially appreciated the fact that every crew member was willing to answer the myriad questions I had;  from specific questions about their job to questions about  how they ended up on the Rainier.

rainbow cb1
Perhaps we should have used some of our sonar capabilities to search for the pot of gold at the end of this rainbow!

At the end of my Teacher at Sea experience I have to conclude that NOAA is one of our country’s best kept secrets.  What other federal agency can bring you such treats as the daily weather report or tide predictions for an entire year, monitor fisheries along our coastal areas, keep track of our changing climate, or survey marine mammals? Of course, you shouldn’t forget all those nautical charts produced by the hydrographers on the Rainier. NOAA’s webpage says it all (http://www.noaa.gov/); from the ocean floor to the top of our atmosphere—and everything in-between. In a world with a rapidly changing climate I can’t think of an agency that is doing more important work.

Many thanks to NOAA and the Teacher at Sea program for providing me with this incredible learning experience.

Even the plates have the NOAA logo!!
Even the plates have the NOAA logo!!

Louise Todd, From the Bridge, September 26, 2013

NOAA Teacher at Sea
Louise Todd
Aboard NOAA Ship Oregon II
September 13 – 29, 2013

Mission: Shark and Red Snapper Bottom Longline Survey
Geographical Area of Cruise: Gulf of Mexico
Date: September 26, 2013

Weather Data from the Bridge:
Barometric Pressure: 1012.23mb
Sea Temperature: 28.4˚C
Air Temperature: 29.6˚C
Wind speed: 6.43knots

Science and Technology Log:

This morning I went up to the bridge to learn about how the NOAA Corps Officers and the Captain navigate and maneuver the Oregon II.  Ensign Rachel Pryor, my roommate, and Captain Dave Nelson gave me a great tour of the bridge!

The Oregon II is 172 feet long and has a maximum speed of 11 knots.  It was built in 1967.  It has two engines although usually only one engine is used.  The second engine is used when transiting in and out of channels or to give the ship more power when in fairways, the areas of high traffic in the Gulf.  The Oregon II has a draft of 15 feet which means the hull extends 15 feet underneath the water line.  My stateroom is below the water line!  Typically the ship will not go into water shallower than 30 feet.

The bridge has a large number of monitors that provide a range of information to assist with navigation.  There are two radar screens, one typically set to a range of 12 miles and one typically set to a range of 8 miles.  These screens enable the officer navigating the ship to see obstructions, other ships and buoys.  When the radar picks up another vessel, it lists a wealth of information on the vessel including its current rate of speed and its destination.  The radar is also useful in displaying squalls, fast moving storms,  as they develop.

Radar Screen
The radar screen is on the far right

Weather is constantly being displayed on another monitor to help the officer determine what to expect throughout the day.

The Nobeltec is a computerized version of navigation charts that illustrates where the ship is and gives information on the distance until our next station, similar to a GPS in your car.  ENS Pryor compares the Nobeltec to hard copies of the chart every 30 minutes.  Using the hard copies of the charts provides insurance in case the Nobeltec is not working.

Charts
Navigation charts

When we arrive at a station, the speed and direction of the wind are carefully considered by the Officer of the Deck (OOD) as they are crucial in successfully setting and hauling back the line.  It is important that the ship is being pushed off of the line so the line doesn’t get tangled up in the propeller of the ship.  While we are setting the line, the OODis able to stop the engines and even back the ship up to maintain slack in the main line as needed.  Cameras on the stern enable the OOD to see the line being set out and make adjustments in the direction of the ship if needed.  The same considerations are taken when we are hauling back.  The ship typically does not go over 2 knots when the line is being brought back in.  The speed can be reduced as needed during the haul back.  The OOD carefully monitors the haul back from a small window on the side of the bridge.  A lot of work goes into navigating the Oregon II safely!

Personal Log:

I was amazed to see all the monitors up on the bridge!  Keeping everything straight requires a lot of focus.  Being up on the bridge gave me a new perspective of all that goes into each station.  We wouldn’t be able to see all of these sharks without the careful driving from the OOD.

The water has been very calm the past few days. It is like being on a lake.  We’ve had nice weather too!  A good breeze has kept us from getting too hot when we are setting the line or hauling back.

Did you Know?

The stations where we sample are placed into categories depending on their depth.  There are A, B and C stations.  A stations are the most shallow, 5-30 fathoms.  B stations are between 30 and 100 fathoms.  C stations are the deepest, 100-200 fathoms.  One fathom is equal to 6 feet.  A fathometer is used to measure the depth.

Fathometer
The fathometer is the screen on the left

John Clark,Headed Home Early, October 1, 2014

NOAA Teacher at Sea
John Clark
Aboard NOAA Ship Henry B. Bigelow
September 23 – October 4, 2013

Mission: Autumn Bottom Trawl Survey
Geographical Area of Cruise: North Atlantic
Date: October 1, 2013

Science and Technology  Log 

A few hours into our shift midnight we get the word we have been expecting for several days – government shutdown. Our mission will be cut a few days short. That reality means the Bigelow has 24 hours to return to its homeport of Newport,  R.I.  It takes us 10 hours and we dock around 1 in the afternoon. With our fisheries operations suddenly declared over comes clean-up time, and we spend the next 6 hours of our shift cleaning up the on‐board fish lab. It is a time consuming but important process. The lab needs to be spotless and “fish scent” free before we can call our work finished on this cruise.  The lab is literally solid stainless steel and every surface gets washed and suds downed so there is no residue remaining.

Eau de fishes
Fish scales hiding under a flap!

Our work is inspected by a member of the crew. If it were the military, the officer would have had white gloves on I believe, just like in the old movies, rolling his finger over a remote spot looking for the dust we missed. But this is a shining stainless steel fish lab so there are two simultaneous inspections going on at once – the one with the eyes and the one with the nose.  It takes us twice to pass the visual inspection as small collections of fish scales are spotted in a few out-of‐the way areas. It takes us one more pass to clear the smell inspection. Up and down the line we walk, we can all smell the faint lingering perfume of “eau de fishes,” but we are having trouble finding it. We keep following our noses and there it is. Hiding under a black rubber flap at the end of the fish sorting line we find a small collection of fish scales revealed  when the flap is removed for inspection.  With that little section cleaned up and sprayed down the lab is declared done! There is a smile of satisfaction from the team. It is that attention to detail that explains why the lab never smelled of fish when I first boarded the ship 10 days ago nor has it smelled of fish at any time during our voyage. There is a personal pride in leaving the lab in the same shape we found  it. Super clean, all gear and samples stowed, and ready for the next crew to come on board – whenever that turns out to be.

The abrupt and unexpected end to the cruise leaves me scrambling to change my travel plans. Like the ship, I have a limited amount of time to make it home on my government travel orders. The NOAA Teacher at Sea team goes above and beyond to rebook my flights and find me a room for the night.

Personal Log 

On the serendipitous side, the change in plans gives me a little time to see Newport, a town famous for its mansions and the Tennis Hall of Fame.  My first  stop is  the Tennis  Hall  of  Fame.  My father was a first class  tennis  player who invested many  hours  attempting to

teach his  son the game. Despite the passion in  our  home  for  the  great  sport  we  never  made it  to  the  Tennis  Hall  of  Fame in  Newport.  Today I get the  chance to fulfill that  bucket  list  goal. I still remember being court side as a young boy at The  Philadelphia Indoor Championships watching the likes of Charlie Pasarell, Arthur Ashe, and Pancho Gonzales playing on the canvas tennis court that was stretched out over the basketball arena. There was even a picture of the grass court lawn of the Germantown Cricket Club from its days a USTA championship venue before the move to Forest Hill, NY. I grew up playing on those tennis courts as my father belonged to that  club. Good memories.

Clark Log 4b

There was also a  “court tennis” court, the game believed to be the precursor  to outdoor  tennis. Court  tennis derived from playing a  tennis  type  game  inside a walled‐in  court yard.  Using  the  roof and  the  wall and the open side windows to beat your opponent is all part of the game. I played court tennis as a  young teen. It’s a very unique game that is only played in a few spots now. There are only 38 court tennis courts in the world and Newport has two of them. If you like tennis, give court tennis a go if  you ever get the  chance.

The tennis court

Thoughts of a leisurely stroll evolve into a brisk walk as I head toward the ultimate and most famous Newport mansion: The Breakers, the 100,000 plus square foot summer home of the Vanderbilt family. This house has to be toured to understand the conspicuous consumption as a  pastime of the then super rich. My 2000 square foot  home would fit entirely inside  the  grand  hall  of  the  Breakers.  In  fact you could stack my home three high and they would still be below the Breaker’s ceiling. A ceiling inspired by Paris, a billiard room with walls of solid marble overlooking the ocean, a floor of thousands of mosaic floor tiles all put  down by hand one by one, a stair case from Gone With the Wind, and 20 bathrooms to choose from all speak  to the wealth and pursuit of elegance enjoyed by  the Vanderbilt clan. It is a lifestyle of a bye–gone era often referred to as the “Gilded Age.” It is  an apt description.

Clark Log 4dClark Log 4e

Clark Log 4g

After sightseeing, it’s off to the bus stop for my shuttle to the Newport Airport where I take off at dawn the next morning to head for  home. I’m  leaving  so  early that the complementary coffee isn’t out yet! After an uneventful flight comes the end to an amazing adventure. Nothing left now except laundry and memories. And lots of great ideas for lesson plans to work into my classes. Thank you NOAA Teacher at Sea Program for offering me the learning experience of a lifetime. I cannot wait to get back and share the experiences with my students.

Clark Log 4h

John Clark, September 27, 2013

NOAA Teacher at Sea John Clark

Aboard NOAA Ship Henry B. Bigelow

September 23 – October 4, 2013

Clark Log 3gMission: Autumn Bottom Trawl Survey
Geographical Area of Cruise: North Atlantic
Date: September 27, 2013

Science and Technology  Log 

It’s going to be a busy night trawling and processing our catch.  Yippee. I like  being busy as the time passes more quickly and I learn about more fish. A large number of trawling areas are all clustered together for our shift. For the most part that means the time needed to collect data on one trawl is close to the amount of time needed for the ship to reach the next trawling area. The first trawl was a highlight for me as we collected, for the first time,  a few puffer fish and one managed to stay inflated so I had a picture taken with that one.

We found a puffer
We found a puffer

However, on this night there was more than just puffer fish to be photographed with. On this night we caught the big one that didn’t get away. One trawl brings in an amazing catch of 6 very large striped bass and among them is a new record: The largest striped bass ever hauled in by NOAA Fisheries! The crew let me hold it up. It was very heavy and  I kept hoping it would not start flopping around. I could just see myself letting go and watching it slip off the deck and back into the sea. Fortunately, our newly caught prize reacted passively to my photo op. I felt very lucky that the big fish was processed at the station I was working at. When Jakub put the big fish on the scale it was like a game show – special sounds were emitted from our speakers and out came the printed label confirming our prize  – “FREEZ – biggest fish ever “-‐-‐the largest Morone Saxatilis (striped bass) ever caught by a NOAA Fisheries research ship.  It was four feet long. I kept  waiting for the balloons to come down from the ceiling.

Catch of the day
Catch of the day

Every member of the science team sorts fish but at the  data  collection tables my role  in the  fish lab is one of “recorder”. I’m teamed  with  another scientist who serves  as  the “cutter”, in this  case Jakub. That person collects the information I enter into the computer. The amount of data collected  depends on  the quantity and  type of fish  caught in  the net. I help  record  data on length, weight, sex, sexual development, diet, and scales. Sometimes fish specimens or parts of a fish, like the backbone of a goose fish, are preserved. On other occasions, fish, often the small ones are frozen for further study. Not every scientist can make it on to the Bigelow to be directly part of the trip so species data and samples are collected in accordance with their requests.

Collecting data from a fish as large as our striped bass is not easy. It is as big as the processing sink at our data collection  station and it takes Jakub’s skill with a hacksaw-‐-‐yes I said hacksaw-‐-‐to open up the back of the head  of the striped  bass and retrieve  the  otolith, the  two small bones  found behind the head that are  studied to determine  age. When we  were  done, the fish was bagged and placed in the deep freeze for  further  study upon our return. On the good side we only froze one of the six striped bass that we caught so we got to enjoy some great seafood for dinner. The team filleted over 18 pounds of striped bass for the chef to cook up.

Too big for the basket
Too big for the basket

More Going On: 

Processing the  trawl is not the  only data  collection activity taking place on the  Bigelow.  Before most trawls begin the command comes down to “deploy the bongos”. They are actually a pair  of  closed end nets similar to nets used to catch butterflies only much longer. The name bongo comes from the deployment apparatus that holds the pair of nets. The top resembles a set of bongo drums with one net attached to each one. Their purpose, once deployed, is to collect plankton samples for further study. Many fish live off plankton until they are themselves eaten by a predator farther up the food chain so the health of plankton is critical to the success of  the ecological food chain in the oceans.

Processing
Processing

Before some other trawls, comes the command to deploy the CTD device. When submerged to a target  depth  and  running in  the water as the ship  steams forward, this long fire extinguisher sized  device measures conductivity and temperature at specified depths of the ocean. It is another tool for measuring the health of the ocean and how current water conditions can impact the health  of the marine life and also the food chain in the area.

Personal Log 

On a personal note, I filleted a fish for the first time today – a  flounder. Tanya, one  of the science crew taught me how to do it. I was so excited about the outcome that I did another one!

Processing fish
Processing fish

Clark Log 3gg

A mix of fish
A mix of fish
Paired trawl
Paired trawl
Learning to fillet
Learning to fillet

Louise Todd, CTD and Samples, September 25, 2013

NOAA Teacher at Sea
Louise Todd
Aboard NOAA Ship Oregon II
September 13 – 29, 2013

Mission: Shark and Red Snapper Bottom Longline Survey
Geographical Area of Cruise: Gulf of Mexico
Date: September 25, 2013

Weather Data from the Bridge:
Barometric Pressure: 1008.6mb
Sea Temperature: 28.3˚C
Air Temperature: 26.3˚C
Wind speed: 8.73knots

Science and Technology Log:

After we set the line, the CTD (Conductivity, Temperature, Depth) is deployed at each station.

CTD
CTD ready to be deployed

This instrument provides information a complete profile of the physical characteristics of the water column, including salinity, temperature and dissolved oxygen.  The CTD is deployed from the bow of the boat using a winch.

Deploying the CTD
Deploying the CTD

When it is first lowered in the water it calibrates at the surface for three minutes.  After it is calibrated it is lowered into the water until it reaches the bottom.  The CTD records data very quickly and provides valuable information about the station.  Conductivity is used to measure the salinity, the amount of salt dissolved in the water.  The CTD also measures the dissolved oxygen in the water.  Dissolved oxygen is an important reading as it reveals how much oxygen is available in that area.  The amount of oxygen available in the water indicates the amount of life this station could be capable of supporting.  Dissolved oxygen is affected by the temperature and salinity in an area.  Higher salinity and temperature result in lower dissolved oxygen levels.  Areas of very low dissolved oxygen, called hypoxia, result in dead zones.  NOAA monitors hypoxia in the Gulf of Mexico using data from CTDs.

The otoliths and gonads are taken from all of the commercially and recreationally important fish like Snapper, Grouper and Tilefish.  Otoliths are used to age fish.  Aging fish provides information on the population dynamics for those species.  The otoliths are “ear bones” of the fish and are located in their heads.  It takes careful work with a knife and tweezers to remove the otoliths.

Removing otoliths
Removing otoliths

Once the otoliths are removed, they are placed in small envelopes to be examined in the lab in Pascagoula, MS.  Otoliths have rings similar to growth rings in trees that have to be carefully counted under a microscope to determine the age of the fish.

Otolith
Otolith

The gonads (ovaries or testes) are removed and the reproductive stage of the fish is determined.  The weights of the gonads are also recorded.  Small samples of the gonads are taken in order for the histology to be examined in the lab.  Examining the gonads closely will confirm the reproductive stage of the fish.  Gathering information about the reproductive stage of the fish also helps with understanding the population dynamics of a species and aids in management decisions.

Personal Log:

Taking the otoliths out of the fish was harder than I anticipated, especially on the larger fish.  It takes some muscle to get through the bone!

Otolith
Otolith removed from a Red Snapper

We have had a few very busy haul backs today.  One haul back had over 50 sharks!  My favorite shark today was a Bull Shark.  We caught two today but were only able to get one into the cradle long enough to get measurements on it.  We tagged it and then watched her swim away!  I can’t believe we are halfway through my second week.  Time is flying by!  I can’t wait to see what is on the line tomorrow!

Did you Know?

Yellowedge Grouper are protogynous hermaphrodites.  They start their lives as females and transform into males as they age.  Yellowedge Grouper are the only species of grouper we have caught.

Animals Seen

Here are a few of the animals we’ve seen so far!

Tilefish
Tilefish (Photo credit Christine Seither)
Sandbar
Sandbar shark in the cradle
Red Snapper
Red Snapper (Photo credit Christine Seither)
Yellowedge Grouper
Yellowedge Grouper (Photo credit Christine Seither)