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TAFS publishes our first Black Sea Bass experiment paper!

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Black Sea Bass have rapidly increased in abundance particularly in Long Island Sound (LIS Trawl survey data).

 

27 December 2023. We are excited to announce that Transactions of the American Fisheries Society just published our first large experimental study on Black Sea Bass overwintering! The work is part of Max Zavell's PhD research and reports on temperature- and food-ration dependent overwinter growth in Black Sea Bass juveniles from Long Island Sound. We reared juveniles individually in two separate experiments, one applying three static temperature treatments (6, 12, 19°C) and another using a seasonal temperature profile to mimic the thermal experience of juveniles emigrating to their offshore overwintering grounds coupled with various food treatments.

We found that Black Sea Bass juveniles showed positive overwinter growth even at temperatures as low as 6°C. However, the best temperature for growth, survival, and lipid accumulation was 12°C, which is close to the presumed conditions at offshore overwintering habitats of this species.

Congratulations, Max, to this great paper! Also, congrats to undergraduate student Matthew Mouland, who helped tirelessly with the rearing and has now deservedly become a co-author.



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(A) total length (TL) growth (mm/day), (B) weight-specific growth (%/day), and (C) growth efficiency (%) of juvenile Black Sea Bass reared at 6°C (blue circles), 12°C (green circles), and 19°C (orange circles) for 42–78 days. Each symbol represents an individual fish.

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Juvenile Black Sea Bass rearing setup in March 2022 in the Rankin Lab. Each white bucket contained an individual fish.

New 2023 sand lance experiment under way!

 

By Lucas Jones.

November 26, 2023. Members of the Sand lance Mafia assembled onboard the F/V Miss Emily in hopes of finding spawning ripe fish for our 2023 experiment. After loading our gear, Captain Kevin navigated us towards the southwest corner of Stellwagen Bank and deployed our beam trawl for our first 10-minute tow.

Boom! From the first tow, fish in spawning condition were brought on board, counted and separated by sex. Now, we just needed to repeat this for 13 more trawls until we had a sufficient amount of fish to start the experiment. After collecting 40+ spawning ripe males and females, we headed back to port wile starting to strip-spawn. This is an all hands on deck process, where we need to work together to evaluate the fish in real time and use the most ripe fish available.

The successful strip-spawn event now marks the start of our most ambitious experiment to date, where DNA and RNA samples will help us further investigate potential mechanisms behind the sand lances high CO2 sensitivity.

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Blastula stage sand lance embryos ~ 24h post fertilization

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The sandlance 2023 team after the first trip to Stellwagen Bank this year (left to right: Sam, Emma Siegfried, Chris Murray, Lucas Jones, Zosia Baumann, David Wiley)

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On 26 November, Lucas is back at the Rankin Lab with the goods!

Hannes starts sabbatical research in Chile

17 Juli 2023. Hannes just moved for 5 months to a small village called Dichato near Concepción in south-central Chile to build and then conduct a large common garden experiment on the Chilean silverside Odontesthes regia.

It's still early, disorienting days - but thanks to the ever optimistic Mauricio Urbina, the collaborator on this project, the mood is good and full of anticipation.

Want to learn more? The Chilean silverside page has it.

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Sun over Dichato at Coliumo Bay on 22 July 2023

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Fishing boat in Dichato. In the background is the Marine Station.

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A dead purple sea urchin

ICES JMS publishes sand lance population structure paper!

5 December 2022. We are proud to announce that the ICES Journal of Marine Science just published our latest sand lance study! The work spearheaded by Lucas Jones and subject of his Masters thesis research has brought together a large, international group of collaborators to better understand the genetic relationships between disparate sand lance populations across their large geographical range. This is an Open Access publication that will hopefully be of use to researchers studying sand lance everywhere.

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Sand lance, a vital forage fish, may be facing new challenges as the oceans warm. Researchers have found two genetically distinct populations of Northern sand lance which may help inform conservation and management decisions. These sand lance were caught off the coast of Greenland (Photo courtesy of Thomas Pederson)


Press release. By Elaina Hancock

Genetic Barriers, a Warming Ocean, and the Uncertain Future for an Important Forage Fish

In the vast oceans, one would assume their inhabitants can travel far and wide and, as a result, populations of a species would mix freely. But this doesn’t appear to be the case for a vital forage fish called the sand lance.

Sand lance are small schooling fish impressively rich in lipids, which makes them a fantastic and significant food source for at least 70 different species ranging from whales and sharks to seabirds, says UConn Associate Professor of Marine Sciences Hannes Baumann.

The Northern sand lance can be found from the waters off New Jersey all the way north to Greenland. Researchers, including Baumann and Ph.D. student Lucas Jones, were interested to see if sand lance constitute a massive, homogenous population, or whether there are genetically distinct groups. Their findings are published in the ICES Journal of Marine Science.

Baumann explains these are important questions to answer when considering conservation and sustainable management of the species, especially since the regions where sand lance live are warming faster than many areas of the planet due to climate change.

Sampling fish from such a broad range is no small task, but two years ago, Baumann and Jones began reaching out to other researchers to see if they had tissue samples to spare. Baumann credits the work to the international group of colleagues who contributed samples including co-authors from Canada and Greenland, and who helped sequence and analyze the data including co-authors from Cornell University.

In all, Baumann, Jones, and the team were able to sequence and analyze nearly 300 samples from a variety of locations across the sand lance’s range using a technique called low-coverage whole genome sequencing. They also sequenced the first reference genome for sand lance.

In a nutshell, Baumann says they found an area on the Scotian Shelf, off the coast of Nova Scotia, where a genetic break occurs. The researchers distinguished two distinct groups, one north and one south of the divide, with parts of the genome differing quite dramatically – namely on chromosomes 21 and 24. Without obvious physical barriers like a mountain range separating the groups, Baumann says it’s logical to ask how these differences are possible.

“That is the scientific conundrum,” says Baumann, and the answer, it appears, lies in the currents.

“When fish from the north reproduce and drift south, they are genetically less adapted to warmer southern waters, even if it’s five or six degrees warmer in the winter, they are just not surviving,” Baumann says. “These populations may be linked by the ocean currents, but the realized connectivity is basically zero.”

Separation of 3 sand lance species based nuclear and mitochondrial DNA (Jones et al. ICES JMS 2022)

Fig02---PCA+haplo_data
(A) Principal component analysis of SNP-based, individual-level covariance matrices with superimposed FST values for each interspecies comparison. The asterisk denotes 5 likely misidentified A. americanus specimens from the Northern GSL (B) Mitochondrial haplotype network of all analyzed specimens, with the number mutations separating congeners.

This finding is a first for the sand lance, but it has been shown in other species such as lobsters, cod, and scallops, and this research adds further evidence to an apparent temperature divide at the Scotian Shelf, and helps demonstrate that temperature is an important factor in survival.

“Example after example shows that the ocean is not as homogeneous a place as expected, and there are all kinds of things that prevent that constant mixing,”Baumann says. “We found another striking example of that.”

When researchers find adaptation in an environment where mixing is continuous, like in the ocean, Baumann says, the question is how it is possible that groups stay different, even though they are constantly encountering other genotypes. That is where powerful genomic methods, like the ones used in this paper, come in handy.

“Parts of the genome in many species have what we call a ‘genetic inversion,’ which means that the genes on the chromosome from one parent have a certain order and the genes on the same chromosome that come from the other parent that code for the same thing, and they’re the same area, but they’re flipped,” Baumann says.

These inversions mean recombination cannot occur; therefore, the genes are passed down through the generations and play an important role in adaptation.

“We discovered on chromosomes 21 and 24 there are whole regions that are completely different and that is like the trademark signature of what we call an inversion because there’s no recombination going on.”

Baumann says that knowing there are genetic and ecological barriers on the Scotian Shelf is important, because with climate change, this barrier may move north and while that may be good news for southern fish, it’s bad news for the fish currently there.

The researchers were also a little relieved in finding two clusters, because had there been many smaller clusters, it could make management and conservation more challenging, especially considering scenarios like the construction of offshore wind parks. Areas potentially well situated for wind turbines can also be habitats for sand lance, and construction disrupts habitats. If there were many, smaller population clusters, a single construction project could pose the risk of completely wiping out a cluster, whereas with more widely dispersed populations, though the local population may be temporarily disturbed, it will not be long before they are able to re-establish after construction is completed.

Baumann plans to focus further research on studying the genetic basis of the thermal divide.

“We want to make sure that this fish is productive and resilient, despite climate change, so we should make sure these areas where they are occurring are protected,” Bauman says. “These decisions should include experts to ensure if there’s an area that is very critical to sand lance, that any disturbance is temporary.”

It isn’t an unsolvable conflict, but it is something that we need to do, says Baumann, who also notes that it is possible that sand lance north of the thermal divide are already suffering more from warming because the region is warming faster.

“It could be that these two clusters have different vulnerabilities to climate change,” he says. “We don’t know that yet but that’s something that should be pursued.”

Hannes & Max at the 45th Larval Fish Conference in San Diego

2 September 2022. After two grueling years of pandemic restrictions, Zoom conferences and meetings, the Baumann lab was as elated as anyone else to attend the first in-person conference again! Hannes & Max went to beautiful La Jolla in San Diego to participate in this years 45th Larval Fish Conference (Aug 29 - Sep 2). The stunning setting of the Scripps campus amidst the sound of the Pacific Ocean breeze provided the right kind of backdrop to again mingle with colleagues, meet fellow graduate students for scientific and just fun discussions, while an eclectic number of talks across the spectrum of Larval Fish and Larval Biology renewed the inspiration for our science. Hannes gave a keynote about our recently published work on sand lance CO2 sensitivity, while Max presented his first conference talk about juvenile Black Sea Bass growth and energy allocation.

A big, heartfelt thanks to Noelle Bowlin (NOAA) and her team for pulling off this remarkable conference during these still uncertain, post-COVID times!

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On 29 August 2022, LFC45 participants mingle in front of the Pacific Ocean at the Scripps Auditorium (people from left to right: Lee Fuiman, Teresa Schwemmer, Max Zavell, Chris Chambers, Tom Hurst, Darren Johnson, Jeremy Miller).

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On 30 August, Hannes talks about potential mechanisms of sand lance CO2 sensitivity

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At the end of a day full of science, two conference participants enjoy the sunset over the Pacific Ocean

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Participants of the 45th Larval Fish / Larval Biology Conference at the Scripps Campus on August 31st 2022


  • Baumann H. 2022. Why are sand lance embryos so sensitive to future high CO2 oceans? Keynote at the 45th Larval Fish Conference, San Diego 29 Aug - 1 Sep 2022
  • Zavell, M., Mouland, M., Schultz, E., and Baumann H. 2022. Overwinter growth and energy allocation of Black Sea Bass juveniles from Long Island Sound. 45th Larval Fish Conference, San Diego 29 Aug - 1 Sep 2022

NCMA2022 experiment update: Phenotyping 1,147 fish

Groton, 24 July 2022. A remarkable week ends with a sense of pride, accomplishment and a good dose of exhaustion. After more than two months of rearing, the silversides from our crosses in May have grown big, and at least for the warm, 26C treatment, they reached their final, intended size (~40 mm). Our rearing job came to a successful end, and now post-doctoral researcher Jessica Rick and PhD-student Maria Akopyan came back to the Rankin Lab equipped with hundreds of tubes and lots of RNAlater to finalize the sampling. This involved measuring the critical sustained swim speed of every individual fish, followed by meticulous measurements, photographs, and eventually an individual tube for preservation in RNAlater. Over the course of 9 days (and over 10h of work each day), the team measured 1,147 fish, which ranged in size between 15 and 50 mm. A big hat tip to the hard-working geneticists!

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On 16 July 2022, Maria (left) and Jessi (right) are working meticulously through their individual sampling protocol of silversides reared for two months at 26C. Every rearing container contains about 40 fish.

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On 21 July 2022, most of the rearing containers have been sampled and only 5 remain.

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Maria is tackling individual length and weight measurments, photographing, labeling and preserving of silversides.

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The old swim flume that has seen its fair share of experimental work, is being put to good use once again.

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To calibrate the dial of the swim flume to flow speeds, we use dye and video recording.


Now, our rearing job still continues until the crosses in the 20C treatment reach their final size, when the second session of phenotyping will need to happen. And of course, there iare so many more steps to follow. Stay tuned.

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On 16 July 2022, Maria looks concentrated while taking a picture of a reared silverside.

World Ocean’s Day at 3rd grade Groton Elementary School

7 June 2022. This is World Ocean Week and many Marine Science students and faculty do their bit to increase outreach to our community. Hannes had the privilege of dropping by the 3rd graders of the Catherine Kolnaski Magnet School, talking about what Marine Scientists do, which ocean critters eat another and "What was the weirdest fish you ever caught?" Oh, and "Are you really sure that the Megalodon [Charchardon megalodon] is no longer alive?" Thank you to Mr. Moon, Mrs. Laudone for the opportunity to come visit the school!

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John and Hannes travel to Bermuda to install a new CO2 system

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The Bermuda Institute of Ocean Sciences (BIOS) with its flagship the R/V 'Atlantic Explorer' in May 2022

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John Hamilton (right) and Hannes Baumann (left), the UConn team for the BIOS CO2 project

29 May 2022. When in a few months researchers and students at the Bermuda Institute of Ocean Science (BIOS) begin using their new outdoor mesocosm facility, they can now manipulate and control the CO2 levels in as many of 9 flow-through basins. The important new capacity of the system will allow realistic ocean warming and acidification experiments and has been the product of a wonderful collaboration between BIOS researcher Dr. Yvonne Sawall and our UConn Marine Sciences team consisting of John Hamilton and Hannes Baumann.

The newly developed system shares some of the design ideas with ALFiRiS, the factorial rearing system we developed and used over the past years at UConn's Rankin Seawater Lab. For example, we again developed and installed a central pH measurement hub that sequentially collects water samples via pumps from each of 12 independent basins, which is advantageous, because it only relies on a single, high-end pH sensor, therefore making measurements always comparable. Similarly, we are using LabView software (National Instruments) to switch pumps on and off and log, display, and graph the pH conditions in real time for researchers to have confidence in their chosen environmental parameters.

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A view over Mullet Bay from Slip Point Lane in St.George/Bermuda

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A downward view of BIOS' outdoor mesocosm facility, still in the middle of the major refurbishment

While most of the planning and design work was done remotely via frequent online meetings, Hannes and John worked with Yvonne during the past week at the BIOS station on installing and testing the systems major components. Working mostly out in the open under a warm and clear Bermudan sky was a particular treat of this assignment. Big shout-out, too, to facilities manager Kevin Hollis for his tireless onsite help!

Despite setbacks in form of supply chain delays and an unfortunate last moment COVID infection preventing team member Lucas Jones from traveling to Bermuda, soon the new outdoor mesocosm facility at BIOS will become operational and allow new and advanced kinds of experimental research on global change biology.


Staying at the Mary and James Buttler suite at BIOS was a particular treat

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The electronic box designed & assembled by John controls the sampling pumps

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On May 24th, John is explaining the workings of the software to Yvonne and Roderick

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On May 26, Yvonne measures pH in a mock-up of the CO2 header tanks for the mesocosm facility

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On May 28, our work is done and we enjoy the evening on the dock of Yvonne's place in St.George

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'Winky' is the queen of BIOS

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The R/V Atlantic Explorer is the flagship of BIOS and the main operation platform for the BATS time series

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John takes a picture of a Royal Poinciana (Delonix regia, Fabacea, Caesalpinioideae), a particularly stunning tree at the BIOS and all over Bermuda

Another crazy road trip for genetic silverside research

15 May 2022. A full, blood red moon rises over Pine Island this Sunday evening. The sight makes not just humans swoon – its pull extents underwater to all kinds of critters that take it as cue for reproduction. Critters just like the Atlantic Silverside, which once again we pursue this season to extract more of its genomic 'secrets'.

Specifically, it is this weekend that we embark on yet another ambitious road trip to find and sample spawning-ripe silversides from two very far apart places: Morehead City, North Carolina and Beverly, Massachusetts. The goal: transport spawners live from each population to UConn's Rankin Seawater lab and produce calculated crosses that will allow studying the role of genomic inversions in local adaptation.

The crew this time are Maria Akopyan and Jessica Rick from Cornell University, along with Lucas Jones and Hannes Baumann from UConn. Big shout-out to Tara Duffy for her help with beach seining at Beverly, MA. During the spawning event on May 15th, Nina Therkildsen also joined the efforts. The design and experiment are part of Jessi's successful NSF post-doctoral fellowship proposal, which the whole UConn-Cornell silverside team supports.

Click through the pictures below to retrace the steps of an exhausting but so far successful effort. Fingers crossed that all goes well during the next weeks, when the fish need to hatch, survive and grow, so they can be assessed for their traits.

Map-trip
The US east coast map illustrates our ambitious sampling plan.

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On 12th May, fog envelopes the Chesapeake Bridge on our drive south to Morehead City, NC.

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Maria, Hannes, Lucas, and Jessi getting ready to beach seine the Morehead City site

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Our 100ft beach seine is being laid out on the Morehead City site.

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On May 13th, Atlantic silversides caught in Morehead City swim in a bucket.

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Lucas checking whether the fish are properly prepared for transport.

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Ripe adult silversides are being transported in large coolers, with proper aeration and water changes underway.

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Maria driving through the night. The long trip back up north is especially taxing.

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On May 14th, Jessi and Tara pull our seine net up the beach on Obear Park, Beverly, MA.

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Maria bringing a new sampling bucket to Jessi and Tara (background) seining.

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Seining at low tide in Obear Park is made more difficult by ankle deep mud.

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On May 15th, at UConn's Rankin Seawater lab, Nina and Jessi strategize about designing crosses.

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On May 15th, Hannes, Jessi, and Nina spawn individual silversides.

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Jessi squeezing a silverside female for eggs in UConn's Rankin Lab.

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A 24 hours old silverside embryo developing at 26C.

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On May 15th, Jessi lays out individual crosses to be reared in the circle tanks in UConn's Rankin Lab.

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Nina and Maria extract DNA from male and female spawners to determine a specific regions homo- vs. heterozygosity.

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Screens with attached embryos are being suspended in buckets for development under two different temperatures.

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A specific capture probe (TARMS gel) allows the quick determination whether adult spawners were homo- or heterozygous for specific inversions on chromosomes 11, 18, or 24

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A silverside larva 6 days post hatch produced from NC spawners. The stomach is full of brine shrimp nauplii, pigmentation just started.

Unveiling a new sturgeon outreach sign at Hammonassett State Park

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On May 7th, project members, CTDEEP, and CT SeaGrant representatives unveil the new outreach sign about Atlantic sturgeon at Hammonassett State Park (f.l.t.r. Mason Trumble, CTDEEP deputy commissioner; Tom Savoy, CTDEEP scientist; Kelli Mosca, CTDEEP; Joe Cunningham, CTDEEP; Hannes Baumann, UConn; Sylvain Deguise, CT SeaGrant Director; Jacque Benway, CTDEEP

May 7th, 2022. Despite the chilly, rainy weather on Hammonassett Park's Meigs Point and the resultant lack of a beach crowd, the mood among the group was elated and proud. For over two years, our lab together with researchers from the Connecticut Department of Energy and Environmental Protection (CTDEEP, Tom Savoy, Jacque Benway) have worked tirelessly to better understand the growth and seasonal movement patterns of Atlantic Sturgeon (Acipenser oxyrhynchus) in Long Island Sound and the Connecticut River. The research project was funded by Connecticut SeaGrant (NOAA Award NA18OAR4170081, Project R/LR-29).

Kelli Mosca did her M.S. thesis research using fin spine sections for growth analyses and telemetry data for movement patterns. After defending in March 2022, she immediately accepted an offer by CTDEEP to become a full time staff scientist. Congrats again, Kelli!

The sign was designed by Joe Cunningham with pictures from Jacob Snyder (RedSkiesPhotography.com). It combines several outreach goals. 1) Convey to people that these ancient, iconic fish actually occur in our waters, 2) teach the interested readers that sturgeon spawn in freshwater and then grow up in saltwater, 3) give readers a sense of the ongoing research on Atlantic sturgeon, 4) tell the public that sturgeon may come back to Long Island Sound and River, but need protection. Particularly, they rely on any accidental catches to be released and reported. The sign is also available in Spanish language to broaden its reach.

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The sturgeon outreach sign at Hammonassett State Park