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20 June 2025. Members of the Baumann lab just returned from the 48th Annual Larval Fish Conference, which was organized this year by Early Life History Section members from the Université du Quebec in Quebec City. This small, international conference convened experts from 16 countries and all career stages dedicated to better understand processes governing fish early life stages (eggs, embryos, larvae, juveniles).
Le Chateau Fontenac is one of Quebec City's most distinctive landmarks
This year, our lab was represented by Hannes, Lucas, Emma, and Vicki - with the latter 3 doing a great job communicating the early findings of their PhD theses research via oral and poster presentations. Lucas shared genomic findings of sand lance in the Hudson Bay and from CO2-sensitivity experiments. Emma presented first insights of experimental research on the inshore sand lance species, and Vicki showed that in- and offshore sandlance species might mix more than previously thought. In addition, Emma helped organize and conduct a well received panel discussion for early career scientists about the art of reviewing and publishing.
Quebec is an incredibly picturesque, historic city - and all of us were lucky to be treated with a banquet dinner at the Quebec Parliament at the end of the conference. Well done, all!
Participants of the LFC48 at the meeting room at the Hotel Concorde
Conference banquet at the Quebec City Parliament
Hannes and Lucas at the revolving restaurant "La Ciel" on top of the hotel
Oral and Poster Presentations at LFC48
Jones, L.F., Schembri, S., Bouchard, C., and Baumann, H. 2025. What sand lance species inhabits the Hudson Bay System in the Canadian Arctic? Oral presentation.
You, V., Batta-Lona, P., O'Donnell, T., and Baumann, H. 2025. Identifying sand lance species and their distributions in the Northwest Atlantic using real-time PCR (qPCR). Poster. /li>
Jones, L.F., Murray, C.S., Zavell, M.D., Siegfried, E., Therkildsen, N.O., and Baumann, H. 2025. Is there a genomic basis to CO2 sensitivity in the Northern sand lance? Poster.
Siegfried, E. and Baumann, H. 2025. Temperature effects on the time to hatch in American sand lance (Ammodytes americanus). Poster.
Quebec City and the mighty St. Lawrence River at night
25 January 2025. We are proud to share that the journal Environmental Biology of Fishes just published our latest sand lance research - this time involving specimen samples from the Canadian Arctic! And it's a story that has all the hallmarks of how scientist collaborate and how such collaborations can evolve and widen over time.
About 5 years ago, we began to receive samples of sand lance from Canadian colleagues who had collected them in places such as the Grand Banks, the Gulf of Saint Lawrence and even in coastal waters of western Greenland. When these samples were compared genetically to sand lance in the south (e.g. Stellwagen Bank) study, it revealed the existence of two large population clusters of Northern sand lance (Ammodytes dubius) on the Northwest Atlantic shelf (Jones et al. 2023). It was also the first genetic study of Lucas Jones, and it earned him his Masters degree in 2022.
A few years later, our Canadian colleague Caroline Bouchard approached us with a related problem. They had collected larval sand lance samples by ship tows in the Hudson Bay - the famously vast, shallow shelf sea in the Canadian Arctic - but there was no way to identify them to species level with traditional tools. If we might be interested to have a - genomic - look?
Lucas - now a PhD student - sure was. After DNA was extracted and sequenced in the same way as with the other samples before (i.e., low coverage whole genome sequencing), he applied his already developed bioinformatic pipeline to answer the question, which sand lance species inhabits the Hudson Bay?
So here it is. As the now published, first chapter of his PhD research reports - the findings were surprisingly unequivocal. All samples clustered with (i.e., were genomically indistinguishable from) the Northern sand lance (A. dubius).
This, we argue in the paper, demonstrated two things: First, the northern genotype of A. dubius forms a genetically homogeneous population across an astoundingly large geographic range of > 2 million km2, and second, there does not (yet?) appear to be any sign of Pacific sand lance species mixing in with the Atlantic species in this region.
Congrats, Lucas, and fingers crossed for your next discoveries of sand lance genomics!
Map of the Canadian Arctic with the Hudson Bay and Hudson Strait. Unknown Ammodytes spp. (red circles) were sampled 2010–2018 and identified as A. dubius using whole genome sequencing (gif turning into blue circles). Known congeners from Jones et al. (2023) with blue circles/shading showing the putative range and sampling sites for Northern sand lance (A. dubius) comprised of a northern cluster (NC, dark blue circles) and a southern cluster (SC, light blue circles), the grey square denoting American sand lance (A. americanus) sampled from a nearshore site in the Gulf of Maine, and yellow diamond/shading denoting the putative range/sampling site for the Pacific sand lance (A. personatus). Green shading depicts putative occurrence of the Arcto-Pacific congener A. hexapterus, which has recently invaded the Canadian Arctic (green circles, Falardeau et al. 2017)
A potential ripple effect from carbon in the atmosphere could have severe impacts throughout the ocean ecosystem
This photo shows sand lance embryos that have and have not hatched. Sand lance have trouble hatching at future ocean CO2 levels (photo courtesy of Emma Cross).
When carbon is emitted into the atmosphere, about a quarter of it is absorbed by the earth’s oceans. As the oceans serve as a massive ‘sink’ for carbon, there are changes to the water’s pH – a measure of how acidic or basic water is. As oceans absorb carbon, their water becomes more acidic, a process called ocean acidification (OA). For years, researchers have worked to understand what effect this could have on marine life.
While most research so far shows that fish are fairly resilient to OA, new research from UConn, the University of Washington, the National Oceanic and Atmospheric Administration (NOAA), and Southern Connecticut State University, shows that an important forage fish for the Northwest Atlantic called sand lance is very sensitive to OA, and that this could have considerable ecosystem impacts by 2100. The team’s findings have just been published in Marine Ecology Progress Series 687.
Sand lance spawn in the winter months in offshore environments that tend to have stable, low levels of CO2, explains UConn Department of Marine Sciences researcher and lead author Hannes Baumann.
“Marine organisms are not living in a uniform ocean,” Baumann says. “In near shore environments, large CO2 fluctuations between day and night and between seasons are the norm, and the fish and other organisms are adapted to this variability. When we stumbled upon sand lances we suspected they are different. We thought that a fish that lives in a more open-ocean offshore environment might be more sensitive than the near-shore fish because there’s just much less variability.”
The project was a collaboration with physical oceanographers, including Assistant Professor of Marine Sciences Samantha Siedlecki and Michael Alexander from NOAA’s Physical Sciences Laboratory in Boulder, Colorado, who modeled CO2 levels in 2050 and 2100 for a specific part of the Gulf of Maine where sand lance spawn. Then Baumann and his team reared sand lance embryos in the lab under experimentally higher CO2 levels matching the projected levels.
There are instances of direct fish mortality as result of elevated CO2, but they are rare, says Baumann. However, sand lance embryos proved to be exceptionally sensitive, and fewer embryos hatched under future oceanic CO2 conditions. The researchers repeated the experiments three more times to avoid jumping to conclusions but each time they observed the same result.
“We found that embryo survival-to-hatch decreased sharply with increasing CO2 levels in the water, concluding that this is one of the most CO2-sensitive fish species studied thus far,” Baumann says.
Sand lances are surely one of the most important forage fish here on the Northwest Atlantic shelf… The humpback whales, sharks, tuna, cod, shearwaters, terns — you name it — they are all relying on sand lance.
With this interdisciplinary approach combining model forecasts and serial experimentation the researchers arrived at a picture that is much more specific.
“We consequently applied principles of serial experimentation, which is a most timely and important topic in ocean acidification research right now,” Baumann says. “Because our findings are backed up by repeated independent evidence, they are more robust than many published ocean acidification studies to date.”
In addition to preventing many sand lance embryos from developing normally, the researchers document a second negative, and novel, response to elevated CO2. Higher CO2 levels appear to make it harder for embryos to hatch.
Baumann explains the lowered pH likely renders enzymes needed for successful hatching less effective, leaving the embryos unable to break through their eggshell (chorion) to hatch.
The results show that by 2100, due to acidification, sand lance hatching success could be reduced to 71% of today’s levels. Since sand lance are such a critical component of the food web of the Northwest Atlantic, this marked decrease in sand lance would have profound impacts throughout the ecosystem.
“Sand lances are surely one of the most important forage fish here on the Northwest Atlantic shelf,” Baumann says. “Their range spans from the Mid Atlantic Bight all the way to Greenland. Where we studied them, on Stellwagen Bank, they are called the backbone of the ecosystem. The humpback whales, sharks, tuna, cod, shearwaters, terns — you name it — they are all relying on sand lance, and if sand lance productivity goes down, we will see ripple effects to all these higher trophic animals. Even though we humans don’t fish for sand lance, we need to take care of the species because it has such a huge effect on everything else.”
Baumann says this study supports the hypothesis that offshore, high latitude marine organisms like the sand lance may be among the most vulnerable to OA. As a result, these organisms and food webs will likely be impacted first and soon, and we must act now.
Previous research has focused on opportunistically chosen species when testing their sensitivity for ocean acidification, says Baumann, but this should change.
“We need strategic thinking about what species we are testing next, because we cannot test every marine fish species, that’s an impossible task. We should concentrate on fish species that are likely the most vulnerable, and therefore the ones that are probably being affected first and this research makes a compelling argument that those are the fish species at higher latitudes and in more offshore than nearshore environments.”
4 March 2022. Hannes was the invited speaker at today's Friday seminar of the Department of Marine Sciences. His talk gave an overview of the research highlights of our multi-disciplinary and multi-institutional efforts to better understand basic ecological facts, population connectivity & structure, and the unusually high CO2-sensitivity of sand lance embryos. The remotely given presentation was attended by 62 people, some of which listened in from as far away as Norway!
The talk was recorded and can be accessed via the public link below.
The unusual ecology and climate sensitivity of sand lance, a key forage fish on the Northwest-Atlantic Shelf
No matter how you look at these small, slender-bodied fishes that at times live buried in sediment or emerge as dense pelagic schools, northern sand lance (Ammodytes dubius) easily awe even the most hard-to-impress scientist or naturalist. Their unusual behavior, patchy occurrence, and reproductive timing are paralleled by their extraordinary importance as forage fish that sustain well-known hotspots of iconic predators (cod, tuna, sharks, seabirds, whales) all across the Northwest Atlantic shelf. And yet, despite their recognized role as the ‘backbone’ of many shelf ecosystems, we still don’t understand many basic aspects of sand lance ecology, population structure and their vulnerability to manmade climate change. Over the past years, our lab has been working alongside other US and Canadian research groups on multiple sand lance projects that have produced stunning new insights into these enigmatic fish. This seminar will outline some of the highlights. We discovered that the seasonal growth of these fish relies heavily on the lipid-rich copepod Calanus finmarchicus and showed that after a dormancy period in summer they spawn on Stellwagen Bank for just a brief period at the end of fall. To resolve questions of connectivity between sand lance areas, we performed large-scale Lagrangian drift simulations that suggested areas of high, low and negligible retention of sand lance offspring and showed overlaps with planned offshore wind lease areas. A large collaborative effort succeeded in obtaining specimens from across the entire distributional range (Greenland to Mid-Atlantic Bight), and subsequent whole genome sequencing newly revealed a stark genomic differentiation between northern and southern population clusters. Last, we performed multiple years of rearing experiments on embryos that consistently showed an unusual sensitivity of sand lance to future, high CO2 oceans. When coupled with regional, end-of-century pCO2 projections we estimate that rising CO2 levels alone could reduce sand lance hatching success to 71% in 2100 relative to today. Warming, acidification, and habitat exploitation therefore emerge as key factors lining up against the future productivity of this forage fish, which is so critically important across Northwest-Atlantic shelf ecosystems.
20 March 2020. We are happy to announce that the prestigious journal Fish & Fisheries just published a comprehensive review about the role of sand lance in the Northwest Atlantic Shelf ecosystem. The article, which came out of a workshop on this topic three years ago, reviews the the current state of knowledge about these enigmatic and important forage fish and urges continued efforts to better understand their role in the ecosystem and sensitivity to climate stressors.
This work represents the first comprehensive assessment of this important forage fish in the Northwest Atlantic, though similar efforts have been carried out in the Pacific Northwest and Europe. In the Atlantic, sand lance are observed to be a significant food source for the federally endangered Roseate tern, Atlantic sturgeon and cod, Harbor and Grey seals and Minke and Humpback whales. “This paper is a call to our peers and colleagues that there is a big gap in knowledge, and to bring more attention to these species as unmanaged forage fish,” says Staudinger.
15 August 2019. The Baumann lab is happy to announce that Chris Murray has started his new chapter of life and science at the west coast with the University of Washington. Congrats Chris, we know you will do great!
Chris started his PhD at UConn/Avery Point in September 2014, after finishing his MS in May 2014 at Stony Brook University, NY. While building on his experience in ocean acidification research, for his PhD he studyied multi-stressor effects of OA and hypoxia on coastal marine fishes. He had an outstanding part in designing and building our factorial larval rearing system ("Larval city") in UConn Rankin Seawater lab. The system allows up to nine independent, static or fluctuating CO2 x O2 environments simultaneously. It has been in full use during spring and summer months of the past four years.
After a phenomenally dedicated four years, Chris defended his PhD in December 2018 and recently graduated with this PhD from UConn.
His thesis titled An experimental evaluation of the sensitivity of coastal marine fishers acidification, hypoxia, and warming
Murray, C.S.*, Wiley, D., and Baumann, H. High sensitivity of a keystone forage fish to elevated CO2 and temperature. Conservation Physiology (resubmitted)
Holding the fort at the Rankin lab were Emma and Sydney, who did an excellent job. Thank you guys!
The Delta Victoria Ocean Pointe Resort was the conference venueBefore the conference, we all attended a workshop on larval fish identification
Whale-watching with Corinne, Julie & Chris
Here is how Julie experienced her first LFC:
Ever since attending the American Fisheries Society conference in 2014, I’ve wanted to go to another fish-focused conference. I was lucky enough to attend the 42nd annual Larval Fish Conference this year in Victoria, British Columbia, and it surpassed all my expectations. The week started off with a larval fish identification workshop where we got to learn techniques from renowned larval fish experts (and see some really cool fish larvae!). The talks were impressive and thought-provoking, providing many new ideas for research and how to give an engaging talk. My favorite part was meeting all the larval fish ecologists whose publications I’ve been reading for my thesis. I spent most of my evenings exploring Victoria with other grad students attending the conference and left with many new friends from institutes all over the world! The trip ended with a whale watch, where we saw a pod of 5 Orcas. Overall, the Larval Fish Conference was a great experience that I hope to someday attend again!
Oral presentations:
Pringle, J. and Baumann, H. Sex-specific growth and mortality patterns in juvenile Atlantic silversides (Menidia menidia) from Connecticut waters. Talk. 42nd Larval Fish Conference, Victoria, BC, Canada 24-28 June 2018
Murray, C.S., Wiley, D., and Baumann, H. Early life stages of the northern sand lance Ammodytes dubius show high sensitivity to acidification and warming in a CO2 × temperature factorial experiment. Talk. 42nd Larval Fish Conference, Victoria, BC, Canada 24-28 June 2018
On this dimly lit November afternoon, rain mercilessly drenched scientists and crew on board the R/V Auk as it slowly navigated the waters of Stellwagen Bank. A world like a wet sponge. Sky and ocean, indistinguishable.
Thanksgiving, the next day.
Despite the circumstances, the team’s mood was nothing short of elated. Our small beam trawl had just spilled hundreds of silvery fish on deck, wriggling like eels. They were Northern sand lance (Ammodytes dubius).
Running ripe adults.
Spawning.
Apparently, they like Thanksgiving, too.
—————
As the ship docked back in the Scituate, Mass., harbor that day, the rain thinned to hazy darkness.
“Let’s get a coffee and then on the road,” mumbled Chris, who led the team, “the real work of the experiments has just begun.”
Chris Murray, a member of the research team, checks the contents of a sediment grab for sand lance. Photo: Jacob Snyder / Red Skies PhotographyThe RV Auk in early morning, getting ready for another sand lance sampling trip to Stellwagen Bank. Photo: Hannes Baumann
Stellwagen Bank, the National Marine Sanctuary just north of Cape Cod, is a true hotspot for some of the Atlantic Ocean’s most iconic creatures: whales, seals, tuna and seabirds, who all share a particular appetite for this one fish – sand lance. Some experts in the sanctuary’s ecosystem call this species its “backbone.” Others consider it a classic forage fish, responsible for transferring massive amounts of energy from lower to upper levels on the food chain.
Sand lance have a few interesting and rare characteristics. They alternate between schooling and foraging in the upper water column and extended periods of being almost completely buried in sand. For that, they rely on sand of a particular grain size and with very little organic content. It’s the kind of sand that defines large areas of the Stellwagen Bank.
Surprisingly little is known about the ecology and ecosystem importance of this sand lance species, although research on its European relatives (A. tobianus, A. marinus) is more advanced. In particular, experiments on early life stages of Northern sand lance have been lacking, save for some pioneering work on rearing methods of the related A. americanus (Smigielski et al. 1984). One question that was of particular interest to our lab involved the potential sensitivity of this fish species to carbon dioxide (CO2). That’s due to two other interesting and rare characteristics of sand lance. They spawn in late fall and winter in cold (and still cooling) waters, which is why their eggs and larvae develop extremely slow compared to other, more typical spring and summer spawning species. In addition, the species is found not in nearshore, but offshore coastal waters, where smaller seasonal and daily CO2 fluctuations more closely resemble oceanic conditions. Could sand lance offspring be particularly sensitive to higher levels of oceanic carbon dioxide predicted during the next 100 to 300 years as climate change effects intensify?
Adult sand lance, shown here, is the favorite food for whales, seals, tuna and seabirds. Photo: Hannes Baumann
Early results suggest that sand lance larva, shown in closeup, are particulary sensitive to higher levels of carbon dioxide. Photo courtesy of Hannes Baumann
Over the past two years (2016-17), we successfully found and sampled spawning ripe sand lance on Stellwagen Bank during a narrow window in late November. Eggs and sperm from adults were removed on board or after being transported live to our laboratory at UConn Avery Point. We reared newly fertilized embryos to hatch and to the feeding larval stage, under different sets of temperature and CO2 conditions, measuring survival and growth traits along the way.
Our experiments are still ongoing, and rearing protocols are being improved.
The preliminary findings, however, are stunning. Survival to hatch was dramatically reduced under elevated and high compared to baseline CO2 conditions. It was severely lowered at higher (10°C or 50°F) compared to lower temperatures (5°C or 41°F). Our second experiment this year appears to repeat this pattern. If these results continue, that would mean sand lance is one of the most CO2-sensitive species studied to date.
General interest in sand lance goes beyond its sensitivity to carbon dioxide. Given the species importance for the ecosystem and coastal economy, there are now increasing efforts to better understand sand lance feeding ecology, distribution and relationship to the rest of the food web. In this regard, funding of our project by the Northeast Sea Grant Consortium proved prescient and a seed for subsequent grants from MIT Sea Grant and the Bureau of Energy Management (BOEM) to continue the work. Surely, the groundswell of interest in sand lance is commensurate with its importance and will enable insights into better management strategies for sensitive ecosystems like those along the U.S. Atlantic coast.
This graphic shows survival to hatch rates of Northern sand lance embryos reared at three carbon dioxide levels and two temperatures. Graphic: Hannes Baumann
Collaborators on this project are:D. Wiley of the National Oceanic and Atmospheric Administration-Stellwagen Bank National Marine Sanctuary; P. Valentine of the U.S. Geological Survey; and S. Gallagher and J. Llopiz, both of the Woods Hole Oceanographic Institution.
17 January 2018. Since November 2017, we have ongoing experiments with offspring of Northern sand lance (Ammodytes dubius), a winter-spawning forage fish of ecological importance along the North-American Atlantic coast. The clip below shows larvae almost two months after fertilization, developing nicely in 5C water and feeding actively on live rotifers. The experiments, led by Chris Murray for his PhD research, study the CO2 sensitivity of this species in our factorial larval rearing system. To our knowledge, this is the first time that this particular species has been reared that far under experimental conditions. Have a look!
Sand lance (Ammodytes dubius) larvae feeding in green water on rotifers
On 19-21 September 2017, Chris Murray and Hannes Baumann traveled to Fort Lauderdale, Florida, to attend the ICES (International Council for the Exploration of the Sea) Annual Science Conference in order to present our ongoing NSF and NOAA funded research on potential ocean acidification effects in Atlantic Silversides and Northern Sand lance. Due to Hurricane Irma, which had impacted all of Florida just a week earlier, it was a great relief that the conference could actually be successfully held.
Chris gave a talk and a poster during this session, which was well received and thus a worthwhile exposure for Chris and our lab’s research.
Murray, C. S. and Baumann H. 2017. Growth costs of high CO2 environments in a marine fish: importance of feeding methodology. Talk.
Murray, C. S., Wiley, D., and Baumann H. 2017. A preliminary study testing the effects of high CO2 on the early life stages of the northern sand lance Ammodytes dubius. Poster.
