May 30, 2018
I was surprised to wake up to a quiet morning today, without hearing the constant bleating of the Bigelow‘s foghorn which is what lulled me to sleep. Since first approaching and then crossing the Great South Channel yesterday we’ve been enveloped in thick fog, which is pretty typical for Georges Bank during the warmer months of the year.
Today however looks fairly clear, which bodes well for Charles Kovach, our man from NESDIS (National Environmental Satellite Data Information Services). His mission, to provide ground-truth in-situ light measurements by lowering hand-deployed radiometers into the water during satellite overpasses, has been a difficult one, with all the cloud and now fog cover that we’ve had during this survey limiting his measurements.
Another collaborative researcher, Andrew Cogswell, from the Canadian DFO (Department of Fisheries and Oceans), has been patiently waiting for us to reach his study area on the northeast peak of Georges Bank and the entire Gulf of Maine.
We are getting close now, having completed 61 stations and are now working our way across the southern flank of Georges Bank, just a dozen stations and one hundred sixty one nautical miles from the Northeast Channel. This year, with warm water anomalies having been discovered in the Gulf of Maine, this area has become the focus of increased interest as a gateway for the influx of this warm water.
We have both bongo tows and CTD rosette casts scheduled to be taken there, so we are hoping to gather some valuable data!
Susan Dee, our NOAA Teacher at Sea from May River High School in South Carolina, has, in addition to helping us with our plankton tows, been busy decorating a NOAA drifter buoy with her school’s name and logo, the Sharks. She is planning to launch it close to the northeast peak of Georges Bank, so perhaps it will also be able to contribute to our understanding of water movements and temperatures in this dynamic area. It will also offer her students a satellite connection via the internet to their teacher’s activities out here with us, as they monitor the buoy’s movements on the drifter website.
Looking ahead, we still have a couple more days of good weather which is helping to ensure our coverage of Georges Bank, but as the high pressure system over us slips off to the east we are facing more marginal conditions this weekend.
Together with the vessel command we’ve come up with a track that will take us across the Gulf of Maine closer to Nova Scotia, where we may get some lee shelter from the forecast northeast winds and be able to continue working, even if at a somewhat slower pace, depending on the seas.
HB18-03 Spring Ecosystems Monitoring Survey
The Henry Bigelow left from Pier 2 at the Newport Naval Station on Wednesday, May 23, under sunny skies to start the Spring Ecosystem Monitoring (EcoMon) Survey. With good weather forecast for the remainder of the week we are heading offshore to survey at the stations along the outer edge of the continental shelf as we head south for the first part of this cruise.
Cruising smoothly at 12 knots with its newly refurbished electric propulsion motors, the vessel is making excellent progress. The time spent approaching our first station is completely taken up by a whirlwind of activities: setting up and testing gear, attending a welcome aboard orientation meeting, and having fire and abandon-ship drills.
As is typical for these ecosystem monitoring surveys, we have a variety of researchers on board: a satellite specialist doing in-situ light measurements during satellite overpasses, a Canadian biologist from the Dept. of Fisheries and Oceans in Halifax, NS, a Maine Maritime Academy student volunteer, a NOAA Teacher-at-Sea from South Carolina, two seabird and marine mammal observers, and three scientists from the Northeast Fisheries Science Center.
Together we will gather as much data as we can on this voyage which will take us from southern New England to Delaware Bay, to Georges Bank and into the Gulf of Maine.
HB18-03 Spring Ecosystem Monitoring (EcoMon) Survey
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.
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.
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.
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.
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.
Aboard the NOAA Ship Henry B. Bigelow
SBTS HB18-02 Leg 4
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.
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.”
Aboard the Henry B. Bigelow
SBTS HB18-02 Leg 3
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.
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.
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.
Aboard the Eagle Eye II
Editor’s note: learn more about the coastal shark survey, last conducted in 2015.