Lobster Shell Disease

While out here on the Bigelow at the southern edge of the Northeast Channel, we’ve caught some lobsters, and just in time. Sailing with us is Joe Kunkel, a former professor and now professor emeritus at UMass Amherst, who is investigating a shell disease found on some lobsters.

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Map showing location of the Northeast Channel

Shell disease is an epizootic, or temporarily prevalent and widespread, disease found on lobsters.  Unofficially, it’s suggested to be caused by a bacterium called Aquamarina.  It’s denoted by circular lesions on the top part of the carapace.  The lesions start out microscopic, but once visible, hundreds of organisms, such as other bacteria, protozoans and nematodes, can be found living in the infected area.  During the 1980s, about 1 in 10,000 lobsters may have been seen with shell disease.  By the late 1990s, hot spots with up to 70% of the population showing signs of lesions were seen in the Narragansett and Buzzards Bay areas.

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Healthy lobster shell – no shell disease. Photo by Christine Kircun, NOAA Fisheries/NEFSC

Joe suggests that the prevalence of the disease increases as the lobsters’ vulnerability to it increases.  This means the shell’s protective ability plays an important role.  Minerals composing the shell include calcium, phosphate and magnesium.  The chemical reactions between these minerals dissolving in the surrounding sea water create a basic (high pH), ‘unstirred layer’.  Think of it as a barrier between the lobster and seawater where a lot of mineral mixing is happening.  Have you ever noticed that a lobster feels a little slippery?  The slippery feeling is that protective barrier.

In order to grow, lobsters molt their hard, exterior shell.  Leading up to molting, a reserve of calcium carbonate and minerals in the endocuticle, or inner shell layer, are resorbed through the epidermal cell layer.  A new, soft shell matrix is formed underneath the old shell.  Once molted, they eat their old shell, bringing all the rest of the minerals back into their body.  They use the resorbed and eaten minerals to establish their new shell.  It takes about seven days for the shell to feel hard, and it’ll be several more weeks until the shell reaches its maximum hardness.  But their new shell has to be bigger so they also need to consume more minerals from their diet.  This time of shell establishment is the vulnerable phase when shell disease may sneak in.

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Lobster with extensive shell disease on its carapace. Photo by Christine Kircun, NOAA Fisheries/NEFSC

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Lobster tail showing extensive shell disease. Photo by Christine Kircun, NOAA Fisheries/NEFSC

If a lobster isn’t able to consume enough added minerals, the new shell could be thinner or weaker in some areas.  As global warming changes the temperature and chemistry of the ocean, lobsters may find it increasingly difficult to obtain the necessary amount of minerals, added to what they already have stored, and regrow a shell to its maximum thickness and hardness as well as building reserves for its yet bigger shell next year.  Possibly, those areas of mineral thinness, or shell weakness, are spots of vulnerability to shell disease.  If the protective barrier isn’t as effective, the lobsters are rendered more vulnerable, giving the bacteria a chance to establish a lesion.

The mineralization is a process that spans multiple years, and the lobsters need an adequate mineral supply to achieve a healthy cuticle that is not vulnerable to infection.  We are making it harder for the lobsters by feeding them low-calcium bait.  We could possibly have a healthier lobster population in the face of ocean acidification if we feed them a higher calcium carbonate bait.  – Joe Kunkel

But if a lobster has shell disease, not all is lost!  If they are able to shed their shell, the disease goes with it, and they are safe.  Unfortunately, it’s not that simple.  First, younger lobsters benefit from multiple molts a year as they are growing very fast.  They are rarely killed because shell disease does not have the time to develop to advanced stages.  For older lobsters, molting is reduced to once a year in the summer.  This means that if the lobster is vulnerable to shell disease due to a compromised shell, it may develop lesions at some point during the year.  As a result, the most severe cases are expected right before molting.  As long as the infection hasn’t made its way through the epidermal cell layer, the lobster has a chance to molt the shell and have a new beginning, disease free with a new shell.  Otherwise, the infection enters the blood stream and kills the lobster.

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Minor shell disease is visible on this lobster shell. Photo by Christine Kircun, NOAA Fisheries, NEFSC

Females have an added hurdle to overcome because they don’t molt while carrying eggs.  Molting for these females may be delayed for up to six months!  This means any lesions on the shell have six more months to reach the blood stream.  Large, healthy and reproductively successful females are extremely important for sustaining a population, so it’s disconcerting to see this condition having an exaggerated effect on females.

But where there are problems, there are people seeking solutions.  One idea is to supplement their diets by feeding lobsters in their traps with bait that contains more minerals needed for shell growth.  Another idea is to harvest them sooner after they molt.  This may decrease the amount of lobsters caught with shell disease as it hasn’t had time to establish itself.  Lobsters with shell disease are usually either discarded or if abundant they are sent to the cannery.  Since the lesions are only on the cuticle, the meat is perfectly fine.   Lobsters with shell disease are not desirable for boiling in the shell because the lovely cherry red color is replaced with a rusted-metal look.

Christine Kircun
Aboard the NOAA Ship Henry B. Bigelow
SBTS HB18-02 Leg 4

Teacher Becomes Sea Student

A unique opportunity that’s offered for teachers to participate in the NOAA surveys is the Teacher At Sea (TAS) program.  It gives teachers from all 50 states, Puerto Rico, Guam and American Samoa the opportunity to participate on our surveys.  This leg, we were fortunate to have Thomas Jenkins from Ohio sail with us on the Bigelow during the spring bottom trawl survey.

With his positive attitude, creativity and excitement to learn, he was the perfect fit!  Aside from teaching 8th grade engineering and general science, he is the science laureate at Teaching Channel, an online community for teachers made up of teachers who provide videos to improve teaching practices, share references and create relevant content to keep up with changes in science, technology and engineering.  As science and engineering standards are increasing, Tom stays ahead of the game by participating in opportunities that give him first hand experiences that he can bring back to his students.

With not knowing exactly what to expect on a bottom trawl survey, Tom was greatly appreciative of everyone’s openness and eagerness to show and teach him everything.  For the most part, he thought the survey would mostly be recording length, weight and sex of the fish.  It was a surprise to find out how in depth the sampling was and how much more work needed to be done after the survey ends.  Most of the information and samples collected undergo further processing and analysis back at the NEFSC labs while other samples were requested from people working on research projects at outside labs or universities.  His excitement to learn was matched by the excitement of the scientific crew to teach.  “If you see something, say something.”  That is always told to everyone sailing.  Either during work-ups or after, everyone was always willing to answer questions and give explanations to any questions.

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Tom works with age and growth technician Jillian Price in the ship’s fish processing lab. Data are entered using the touch screen at right for easy retrieval when the cruise is completed. Photo by Christine Kircun, NOAA Fisheries/NEFSC.

Tom compared experiencing this survey to feeling like a 7-year-old and seeing everything for the first time.  It’s no picnic living in a marine environment, and to successfully thrive in this mysterious ecosystem, the adaptations marine organisms evolved are “so different and cool!”  “The diversity was amazing!”

In particular, he was fascinated with the monkfish.  It uses its illicium, a modified dorsal ray, to lore prey to its giant mouth and move it to its stomach using the many sharp teeth in the front and back of the mouth, like a conveyer belt.  Another animal that sparked Tom’s interest was the longhorn sculpin with its head covered with many sharp spines and the vibrating hum it makes when agitated.  Toward the end of the trip, we started catching lobster, and Tom was excited to hold a lobster whose one claw was the size of his hand!

His students are a clear passion!  In-between tows and after shifts, Tom could be found working on his blogs and collecting information and video capturing different phenomena, such as counter shading, eating habits, pressure changes, and defense mechanisms, to name a few.  He was constantly brainstorming ideas for interactive lesson plans that explain those phenomena.  For example, he mentioned a lesson that would have his students engineer different types of mouths and try to pick up various objects as a way to understand that examining a fish’s mouth is a great way to get an instant idea of their diet.

His students didn’t have to wait for Tom to be back in the classroom to be a part of this journey.  He used social media, Facebook, Instagram and Twitter to communicate informally with his 120 following students!  As he posted daily pictures and updates, they asked him questions and received a quick reply.  And the fun will continue when he returns to his classroom.

After 3 weeks of being away from family and friends, Tom was ready to go back and share everything he learned!  And with all his video footage, he’ll have plenty of work to keep him busy for a while.

The Teacher At Sea program is a great way to establish networks and opportunities between Tom, his current and future students, the Teaching Channel community, and the crew and scientists on the ship.  It’s always important to encourage and empower a strong scientific community.

Overall, Tom would definitely come back if the opportunity presented itself!  “Meeting people who are excited about what they do and who they work with, and learning something new re-energizes me, and makes me want to share the information.”

Christine Kircun
Aboard the Henry B. Bigelow
SBTS HB18-02 Leg 3

More shark species seen on Leg 2 of coastal shark survey

The F/V Eagle Eye II set sail from Cape Canaveral on Monday, April 16, for the second leg of the coastal shark survey. The first leg of the survey saw mostly Atlantic sharpnose, tiger, blacktip, sandbar and hammerhead sharks coming up on the line. The start to the second leg brought more of the same but included a few more species.

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A dusky shark on the line before being brought aboard for tagging and later release.

A dusky shark in the range of 9’ fork length (FL) and two bull sharks in the range of 7’ FL were nice to see on the line. All three were tagged and released in excellent condition. In addition, this year’s first blacknose sharks were caught, tagged, injected with tetracycline and released.

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A bull shark is about to be brought aboard, measured and tagged.

We are looking to get one more station before seeing some potentially rougher weather put a damper on fishing efforts. Hopefully the forecast improves and the scientists and crew are able to continue working.

Joe Mello
Aboard the Eagle Eye II

Editor’s note: learn more about the coastal shark survey, last conducted in 2015.

Safety First!

Note: The NOAA Ship Henry B. Bigelow is currently at sea working along the Northeast U.S. shelf south of New England on the annual Spring Bottom Trawl Survey.

All images and text by Christine Kircun, NOAA/NEFSC

Safety is an issue that everyone on the ship takes very seriously.  Fire extinguishers, fire stations, emergency escape breathing devices (EEBDs), immersion suits, defibrillators, and personal flotation devices (PFD) can be found all throughout the ship.  Drills are designed by an officer who creates an emergency situation which could be a fire or chemical spill.  The emergency is always in a different area, and sometimes if it’s a fire drill, a smoke machine is used which definitely adds an element of reality!

Drills are practiced once a week, and every single person aboard ship has a job during the drill.  It could be investigating the emergency, directing communications/activities, or mustering to a safe place, to name a few.  Once the alarm for the fire drill is set off, one ten-second tone, everyone immediately stops what they’re doing and heads directly to their assigned muster.  The ship crew split into on-scene, damage control (DC) locker forward, DC locker aft, engine room, and bridge groups.  The on-scene group is first on the site to assess the emergency.  Depending on where, what, and severity of the emergency, people from the DC lockers will assist with any needed equipment or personnel.

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Emergency Escape Breathing Devices (EEBDs, orange boxes at left)) and defibrillators (black bag) are part of the ship’s safety equipment.

Meanwhile, the bridge is monitoring the events and guiding the responders.  The crew in the engine room have the ability to control the electric grid to either divert electricity from the hazardous area or make sure there is power for some other necessary task.

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When the fire is extinguished and area secured, a fire hose is cleaned out by shooting water over the side.  This tests the pump and keeps the inside of the hose clean.  After the crew remove their gear and clean up the tools, the abandon ship alarm sounds with six short and one long tone.  The crew grabs some Emergency Position Indicating Radio Beacons (EPIRBs) and joins the scientific party on the bow.  We practice dressing into our immersion suits to make sure it fits, there are no holes, and there’s a light and whistle attached.  When everyone is finished, the captain announces “secure from drills and heed all further alarms,” and it’s back to regular ship life.

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Members of the science party practice dressing into immersion suits, sometimes called Gumby suits, to make sure it fits, there are no holes, and there’s a light and whistle attached.

Occasionally, we’ll practice a man overboard drill which is announced by three long tones.  For this drill, a dummy or some floating object is thrown overboard.  The science crew musters to the flying bridge as lookouts.  Some crew are stationed at the hospital room and others ride out in a Rigid-Hulled Inflatable Boat (RHIB) to retrieve the “man overboard”.  The cold water makes a fast retrieval paramount for the victim’s survival, so it’s best to avoid falling over!

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A Rigid-Hulled Inflatable Boat, or RHIB, on the Bigelow is used for science and ship operations, including drills for a “man overboard.”

There is a chemical hood onboard for preserving stomach and gonad samples.  Gloves are always worn when filling sample jars, but in case of an accident, there is a spill kit and body/eye wash station nearby.

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Chemical hood with safety equipment, including gloves and goggles (left) and the eye wash station (right).

PFDs (personal flotation devices, or life jackets), helmets and man over-board beacons (MOBs) are always worn while working on the back deck.  When wet, the MOB sends a signal to the bridge that someone is in the water.

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Man overboard beacons (MOBs)

Safety drills aside, we are also encouraged to be mindful of tripping hazards, heavy weather doors, wet stairs, hot electrical boxes, slippery floor surfaces, dryer lint traps and in general, keeping one hand free to help you move around the ship.  One rogue wave could easily throw you down a staircase!  Ultimately, a successful trip is one where everyone comes back uninjured and alive.

Christine Kircun, biologist
Onboard the NOAA Ship Henry B. Bigelow
HB 18-02 Leg 3

 

Sampling is in Full Swing on the Spring 2018 Bottom Trawl Survey

Post and Photos by Christine Kircun, NOAA/NEFSC

The spring survey has officially begun, and I am on night watch with a great team!  After a couple of nights to adjust to the sleeping schedule, we’re back in the full swing of sampling.

Not all fish are sampled the same.  For some species, such as shortnose greeneye (Chlorophthalmus agassizi), only lengths are taken.  For others, such as bluefish (Pomatomus saltatrix), we take length, weight, sex, maturity, stomach contents and otoliths.  The bluefish pictured is a 46.5cm (just over 18 inches long) resting (after spawning) female.

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A longfin squid and unidentified squid were found in the stomach (image below).

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Since the otoliths (pictured below) for bluefish are very fragile, the heads are frozen so the otoliths can be taken out back at the lab.

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This is the most common workup.  There may also be additional requests from researchers inside and outside the lab for fin clips, gonad samples, muscle samples or whole frozen fish for identification, maturity, and stomach workshops.

For this leg, we’ve had some beautiful weather.  On night watch, it’s sometimes easy to forget to go outside, but on those nice days, it’s wonderful to feel the sun and watch the water, hoping to catch a glimpse of a shark, fish, or pod of dolphins.

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Though, it’s not always sunny and calm, and we had a little window of unpleasant weather.  When the waves and wind are too rough to fish, the main job becomes not

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Seas are getting rougher and winds are increasing as another storm approaches. 

flying out of your chair when the ship takes a roll, keeping your balance while walking, and trying not to get sick.  If you’ve never been sea sick, count yourself lucky because it is miserable.  But that’s just another part of life on a ship.  Sometimes it’s really tough to be out here, but ultimately, it’s all worth it.  There’s a lot of dedicated and excited scientists, volunteers, officers, deckhands and engineers who are all committed to gathering the best data possible, no matter what.

Christine Kircun
NEFSC Fishery Biology Program, Age and Growth Technician
Aboard the NOAA Ship Henry B. Bigelow
HB18-02-Leg 1

Don’t put all your eggs in one gravel bed!

Don’t put all your eggs in one gravel bed!

Men in waders, steel cylinder chutes read for salmon eggs

From left to right, Graham Goulette (NEFSC) deposits eggs into a cone while Jeff Murphy (GARFO) readies another cone for Peter Ruksznis (ME-DMR) who is using the water cannon to disperse sediments from the gravel. Photo credit – NOAA

Each winter from mid-February to early March, biologists from the Maine Department of Marine Resources (ME-DMR), Penobscot Indian Nation (PIN), Northeast Fisheries Science Center (NOAA/NEFSC), Greater Atlantic Region Field Office (NOAA/GARFO), Maine Inland Fisheries and Wildlife (ME-IFW), and the Natural Resources Conservation Service (NRCS) embark on a collaborative effort to “plant” Atlantic salmon eggs into gravel-bottomed Maine Rivers and streams.  The egg-planting technique has been used in Maine’s salmon rivers for the past decade to help restore and conserve this endangered species. We plant fertilized eggs, collected from adult salmon at a U.S. Fish and Wildlife Service hatchery, directly into spawning habitat to provide an alternative stocking method.

 

The method has been successful in producing juvenile salmon, but it does take a certain amount of effort. This year, an initial investigation into ice conditions revealed that at least one site needed to be cleared of ice before planting could occur.

 

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Biologists from NOAA, ME-DMR, ME-IFW, NRCS, and PIN work to remove ice from the Pleasant River to gain access for egg planting. Photo credit – NOAA

The day prior to planting, a robust group of handsome biologists from several agencies snowmobiled into the site to chip away ice and expose the gravely stream bottom.

After a few hours, with the hard work completed, we indulged ourselves with a late lunch of hot dogs cooked over a trail-side fire and enjoyed the camaraderie of discussing how great egg-planting would be the next day.

 

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Enjoying a late trailside lunch after chiseling and chopping ice. Photo credit – NOAA

 

The following day, we met at the Maine Department of Marine Resources office to pick up the gear and eggs left by the U.S. Fish and Wildlife Service. We loaded all the gear into the trucks and drove the hour and a half to our parking area near the Pleasant River. We then loaded all the gear onto our snowmobiles. We rode several miles on winding trails to get to our remote site. We had some minor sled issues, but we made it! Once on site, with arms akimbo we surveyed the river, realizing the water was too high for planting. Melting snowpack within the drainage had raised the river level higher than the depth of our planting cones. So we headed to another site further downstream where the water level wasn’t so high.

 

Men loading gear onto snow mobiles

From left to right, Peter Ruksznis (ME-DMR), Dan McCaw (PIN), and Ben Naumann (NRCS) prepare to haul ice chiseling gear from the snowmobiles down to the Pleasant River. Photo credit – NOAA

Donning snowshoes, we hauled our gear in a pull sled down a steep embankment to the river and out onto the ice. More than one biologist may have fallen during this trek, but none were seriously hurt. Once on site, we got to work assembling the planting gear and preparing for planting.

 

 

To plant, one crew member operates a water cannon through an aluminum cone sending a jet of water into the gravely river/stream bottom that blasts fine sediments away to create more space in between individual pieces of gravel for the eggs to occupy. Another crew member deposits 400 to 800 eggs into each cone. After the eggs sink to the bottom – below the surface of the substrate – another crew member slowly pulls the cone up from the gravely river bottom, causing water suction to fill the the spaces with eggs. This method mimics the natural process used by adult Atlantic salmon.

 

Placing salmon eggs in a large bucket

Jason Valliere (ME-DMR) prepares salmon eggs for planting by removing them from the insulated cooler and placing them into a bucket filled with river water. Photo credit – NOAA

  At one point during the planting we noticed a small predator of Atlantic salmon eggs – a slimy sculpin. With my catlike reflexes, I was able to scoop the little fella up barehanded and relocate him to a place away from the planting. Not on my watch sucker – I mean sculpin!

 

Depression in the stream bed gravel

“Nest” like depression in the gravel substrate after eggs have been planted and the cone removed. Fine sediments have been forced from the substrate to a depth of 8 – 10 inches creating more space between gravel bits for the eggs. Photo credit – NOAA

 

Working like a well-oiled machine, we planted about 120,000 eggs in a couple hours! These eggs will hatch within a few weeks and remain in the gravel habitat as sac fry for another few weeks before emerging and feeding. Over the next couple weeks more than one million eggs will be planted in multiple rivers and streams. We hope many will survive the next couple years in the rivers, growing to a length of about 6 to 8 inches, before heading to the ocean to become big, beautiful adult salmon.

 

Graham Goulette, salmon biologist

Northeast Fisheries Science Center

 

Atlantic Salmon Sampling in Greenland Continues

Here in Qaqortoq the sampling has been going well the past two weeks and I’ve collected data on over 200 Atlantic salmon from the local market. There have been a couple slower days with fewer than half a dozen salmon, but on the flip side I’ve had days with over 40 salmon! I’ve been able to build a nice rapport with many of the fishermen who now often bring their catch directly to me and the sampling equipment before putting their salmon out for sale. On Tuesday I mentioned to the market manager that I wanted to do something for the fishermen and would be bringing pastries for them on Thursday. I meant for it to be a surprise but on Thursday “my regular” fishermen showed up with 44 Atlantic salmon! Maybe it was a coincidence, but I think the pastries had something to do with it – especially since the market manger told me they were looking forward to eating “cake.”

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View of Qaqortoq from a nearby hillside. Photo credit: Graham Goulette, NEFSC/NOAA Fisheries.

Nearly every day a different cruise ship pulls into the harbor in the morning and an array of tourists from Western Europe, Australia, China, North America, etc. descend upon Qaqortoq to visit the local shops, cafes, and the market. I’ve had the opportunity to explain the West Greenland sampling program to many of them and they all appear very interested in the work being conducted. I explain the biological data I collect helps determine the health of the fish, the scale samples are used to age them, and a small tissue sample collected can be analyzed to identify the region of origin (i.e. the country and even region within a country that the salmon originated from).  I also do my best to explain the purpose of some of the other samples which I am collecting at the request of cooperating scientists from across North Atlantic (i.e., presence and counts of sea lice). Of course the tourists are surprised to see the array of critters for sale at the market in addition to the fish; seal, porpoise, whale and seagulls. Personally, I tried everything except the sea gull. Most wasn’t too bad, but I had to force a grin while chewing and swallowing the raw whale meat and skin.

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ASERT biologist Graham Goulette holds a large Atlantic salmon ready to be sampled. Photo credit: Audrey Dean, University of Waterloo.

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ASERT biologist Graham Goulette weighs an Atlantic salmon at the outdoor market in Qaqortoq. Photo credit: Audrey Dean.

There have been several days at the market without the market manager. On one such day I found myself trying to assist the fishermen with negotiating the sale of fish to a cruise ship. The ship’s personnel only spoke Dutch and English, and the fishermen speak either Greenlandic or Danish (or both), so there was a bit of confusion and all I could think to myself was “please don’t screw this up!” However, my familiarity with the prices of fish and which catch belonged to which fisherman helped the transaction go smoothly.

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A large Atlantic salmon brought to the market by a local fisherman. Photo credit: Graham Goulette, NEFSC/NOAA Fisheries.

Audrey Dean, a colleague and graduate student from the University of Waterloo in Canada, has arrived and will be taking over the sampling for this international effort. I’ve spent a couple days showing her how to sample the Atlantic salmon at the market and getting her acquainted with the fishermen. The data she collects, along with all the data from other biologists located in different Greenlandic communities, will be compiled, analyzed and reported to the International Council for the Exploration of the Seas (ICES)s’ Working Group on North Atlantic Salmon (WGNAS). The WGNAS will use these data as inputs to their international stock assessment efforts to assess the status of Atlantic salmon populations across the North Atlantic.

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University of Waterloo graduate student Audrey Dean collects a scale sample from an Atlantic salmon at the outdoor market in Qaqortoq. Photo credit: Graham Goulette, NEFSC/NOAA Fisheries.

I’m going to remember my time here in Qaqortoq well, but my photos can’t capture the real beauty of the village and landscape (and I took Photography I and II …over 20 years ago in high school). The experience has been great and I’m fortunate to have had such an awesome time here in Qaqortoq, but I’m ready to be home in a few days. The fishermen, and the entire community, have been very friendly and welcoming, but I’m excited to see my wife and kids! And our dog, Benny, too!

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Friendly looking Atlantic wolffish. Photo credit: Graham Goulette, NEFSC/NOAA Fisheries.