Projects
NSF-REU student Elizabeth Estrada had a busy summer
Posted on by Hannes Baumann
8 August 2025. For 10 weeks in summer 2025, Elizabeth Estrada, a rising junior at Riverside City College in Riverside, CA, joined our lab to experience fish ecology research. She applied herself to two contemporary topics - (a) the morphometric relationships between Black sea bass predators and their crustacean prey and (b) the diurnal behavior of juvenile American sandlance in captivity. Ever curious, Elizabeth learned what motivates this research, contributed valuable data and observations, and shadowed other graduate students to observe molecular techniques.
And Elizabeth's artistic talents in drawing animals will leave a truly lasting legacy at our lab!
Thank you so much for your hard work, curiosity and inspiration, Elizabeth! The whole Baumann lab wishes you all the best for the future!
Elizabeth summarized her summer research findings during one poster and one oral presentation.
- Estrada, E., Siegfried, E., and Baumann, H. 2025. Diurnal Burying Behavior of Ammodytes spp. REU final colloquium, Avery Point 6 August 2025
- Estrada, E., Roby, H., and Baumann, H. 2025. Breaking it down: do bigger fish eat bigger shrimp? REU outreach event to the broader public at Mystic Aquarium. 22 July 2025
You can reach Elizabeth at eestrada75@student.rccd.edu
Can adult black sea bass overwinter in Long Island Sound?
Posted on by Hannes Baumann
18 July 2025. We are thrilled to share that Marine & Coastal Fisheries (an AFS Journal) published today the 3rd chapter of Max Zavell's PhD research! The paper asks the simple but pertinent question
Can adult Black Sea Bass overwinter in Long Island Sound, USA?
The research followed the fate of 2 x 25 adult black sea bass that were angled in Long Island Sound (LIS) in fall 2022 and then kept at realistic winter inshore temperatures in two large flow-through tanks at the Rankin Seawater Laboratory of the University of Connecticut at Avery Point. The authors repeatedly measured survival, length- and weight growth, gonad investment and lipid contents of experimental and wild fish. They cautiously conclude that
"At present, overwintering in LIS appears possible but likely disadvantageous for Black Sea Bass, because offshore winter migration results in greater energy reserves and subsequent reproductive investment. In the future, however, warming coastal waters will continue to shorten the duration of unsuitable winter temperatures, which could become conducive to year-round inshore residency or partial migration patterns in the northern stock of Black Sea Bass."
The article was published Open Access. Congratulations, Max et al.!
- Zavell, M.D.*, Mouland, E.P.*, Barnum, D.L.*, Matassa, C.M., Schultz, E.T., and Baumann, H. (2025)
Can adult Black Sea Bass overwinter in Long Island Sound, USA?
Marine and Coastal Fisheries 17:vtaf014 (published Open Access online 18 July 2025)
Hannah & Kaitlyn present black sea bass research at SNEC2025
Posted on by Hannes Baumann
25 June 2025. Our lab's black sea bass experts, PhD student Hannah Roby and undergraduate assistant Kaitlyn Tripp, presented first findings of their CT SeaGrant funded research on black sea bass diets at the summer meeting of the Southern New England Chapter of the American Fisheries Society in New Britain, CT. Hannah's analyses of black sea bass stomach contents are highly anticipated, because they will allow to better understand how the food web in Long Island Sound will be impacted by the explosive abundance increase of this fish.
In addition, Hannah received an award (Norbert Stamp Student Award) for her ongoing work with anglers in and around Long Island Sound.
Well done, all, good job spreading the word about the work we do!
- Roby, H., Tripp, K., Matassa, C., Batta-Lona, P., and Baumann, H. 2025. Digesting the evidence: Black sea bass and trophic impacts in Long Island Sound. Oral presentation. SNEC AFS 2025 Summer Science Meeting 2025, New Britain, CT, 25 June 2025
- Tripp, K., Roby, H., and Baumann, H. 2025. Morphometric relationships between Black Sea Bass and their crustacean prey in Long Island Sound. Oral presentation. SNEC AFS 2025 Summer Science Meeting 2025, New Britain, CT, 25 June 2025
Our lab presents sandlance research at LFC48 in Quebec!
Posted on by Hannes Baumann
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).
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!
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.
Could Endangered Sturgeon Make a Comeback in the Connecticut River?
Posted on by Hannes Baumann
reposted from UConn Today 30 April 2025
Fish that swam next to the dinosaurs are once again appearing in CT waters
By Elaina Hancock
For 160 million years, long-lived and highly migratory Atlantic sturgeons have made their way from the ocean to freshwater spawning grounds inland. The Connecticut River was one of the waterways sturgeon sought out – that is, until they were fished nearly to extinction in the early 20th century.
In 2014, however, researchers from the CT Department of Energy and Environmental Protection (CT DEEP) caught a few juvenile sturgeons in the Connecticut River, implying that sturgeons were spawning there again. More little sturgeon appeared in 2020 and again in 2022, leading some to wonder if this iconic fish that swam next to the dinosaurs was indeed making a comeback in our regional waters.
A new study from UConn professors Hannes Baumann from the Department of Marine Sciences and Eric Schultz from the Department of Ecology and Evolutionary Biology, in collaboration with researchers from CT DEEP including Kelli Mosca ’22 MS, Jacque Roberts, Thomas Savoy and Evan Ingram from Stony Brook University, shows that we have much to learn about sturgeons and that it may not be too late to give them a chance for recovery. Their findings are published in the National Oceanic and Atmospheric Administration’s open access journal, Fishery Bulletin.
Baumann says the project started at a conference in 2019, when he connected with researchers at CT DEEP who pitched a potential collaboration with Mosca, who was a CT DEEP seasonal resource assistant at the time and was hoping to pursue a graduate degree and focus her research on sturgeon. Despite these sightings, Baumann says he was skeptical that the fish were having a comeback, but he was interested in the project.
“These fish spawn in freshwater and then they develop until they are about 50 centimeters in size, then they travel to the ocean so if you find a little sturgeon in the Connecticut River, it must have been born there,” says Baumann. “We know there are sturgeon entering the Connecticut River; then the question is, how far do they go?”
For the project, Baumann secured funding from Connecticut Sea Grant, Mosca joined Baumann’s lab, and they started analyzing data to study sturgeon movement in the Connecticut River.
In 1998, sturgeons became a protected species but only after their situation had become dire. They are now heavily regulated, and even getting permits for research is not an easy task, says Baumann.
The researchers took samples of their pectoral fins that indicate the fish’s approximate age. Mosca looked at samples taken from the fish to determine the age,
“Ageing fish is often compared to ageing trees, in the sense that just as trees gain a ring in their trunk for each year they’re alive, a fish adds what we call an annulus (ring) to various hard parts in their body each year they are alive. In sturgeon’s case, they are not fully calcified, meaning there are not many hard bones to choose from to age. However, a small piece of their pectoral fin is hard enough to create those rings and can thankfully regrow so there is no deleterious effect on the fish. I am thankful to have access to such a large archive of these samples, which are rare given the endangered status of this species,” says Mosca.
People have also tagged these fish with acoustic transmitters, a specialized tag that send out a signal which is then picked up by listening equipment called receivers. CT DEEP deploys receivers anchored along the Connecticut River and within Long Island Sound that record the tag data as tagged sturgeon swim by.
The researchers used data on tracked sturgeons over the course of the three-year study, and over that period, sturgeons were detected as far upriver as Wilcox Island (Middletown, at river kilometer 52).
“In theory, it’s all very easy, you just have to download the data and look where the sturgeon are,” says Baumann. “In practice, there are lots of statistics and analytical steps to properly assess these data. There were something like 1.5 million detections, over the three years in total, so 1.5 million rows of data, where every ping was a sturgeon somewhere. This corresponded to 85 individuals tracked over three years.”
Tracking animals in this way is called acoustic telemetry, and Baumann says the technology has profoundly changed our understanding of animal movements in the wild. There were some surprises in this one, he notes.
“Instead of just episodic accounts of single individuals, this study stands out for the large number of tracked fish,” says Baumann. “It showed that sturgeons generally arrive in the estuary in spring and leave in fall and that most stay in the brackish estuary. But intriguingly, a lot of the fish are indeed making these long upstream excursions into the freshwater. Why would they do this?”
Baumann says that the initial, most intuitive explanation of the fish displaying spawning migrations appeared unlikely after closer inspection. This is because most of the fish were not of adult size and age and, therefore, too young to spawn.
“We always thought Atlantic sturgeon are only in the estuary when they are young, and it is only when they want to spawn that they go into the freshwater. But that appears to be false. Our study shows that almost every size of sturgeon travelled into the freshwater portion of the Connecticut River. We had two individuals in our data set who were 18 years old. Most of the fish that we caught were younger than 12 years, and the average was about eight years, so they’re youngsters,” says Baumann.
The data therefore revealed that Atlantic sturgeons are using the entire Connecticut River, not just the estuary. Baumann says their working theory is that the fish are exploring other areas to find food, since the estuary can become crowded in the summer.
“In the paper, we advanced a theory that some of these Atlantic sturgeons move further up the river due to competition because it’s getting too crowded. The gist is we now know that we need to protect sturgeons at least during these important summer months, when they are in the entire Connecticut River.”
These findings are promising and important for ensuring measures are in place to help give the sturgeons the best chance possible at making a recovery. Though Baumann cannot say with certainty that the population is growing, a hopeful indication is that sightings of juveniles likely born in the River are happening more frequently.
“The sightings are still very sporadic and sort of ephemeral, but perhaps it’s a start.”
Protecting a highly mobile species like sturgeons can be tricky because they recognize no borders. Therefore, it takes national, federal, and international cooperation, but other measures are also important to ensure people are aware of their presence to help reduce accidental boat strikes or bycatch in commercial fisheries.
“From a logical perspective, they have been fished to quasi extinction in the beginning of the 20th century. Indeed, it would be a small miracle if these fish came back,” says Baumann. “At the end of the day, they made it 160 million years, and we need to just give them a chance to make it another 100. It doesn’t take much. It does take time, but if we allow it, I’m convinced that nature will find a way.”
- Mosca, K.C., Savoy, T., R. Benway, J., Ingram, E.C., Schultz, E.T., and Baumann, H. (2025) Age structure and seasonal movement patterns of Atlantic sturgeon aggregating in eastern Long Island Sound and the Connecticut River Fishery Bulletin 123:127-142
What sand lance species inhabits the Hudson Bay?
Posted on by Hannes Baumann
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!
- Jones, L.F., Schembri, S., Bouchard, C., and Baumann, H. (2025)
Molecular identification of larval sand lance (Ammodytes spp.) caught in the Hudson Bay System 2010-2018
Environmental Biology of Fishes (published online 25 January 2025)
Beachseining at night. In a snowstorm. For sandlance.
Posted on by Hannes Baumann
10 December 2024. Emma and Hannes just returned from another trip to Wells Harbor in Maine, where we had been sampling and monitoring a local population of American sand lance (Ammodytes americanus) over the late summer and into fall. This was definitely a trip for the history books. Not because of the sand lance, mind you (we caught a total of 7), and certainly not for the beauty of the scenery either. We had hoped to catch these fish close to the begin of their spawning season (which starts around December) at low tide in the harbor, reasoning that our chances would be better at night. What we hadn't in mind was the snow storm that began walloping coastal Maine just as we arrived at the site. But what's a (slightly nutty) biologist to do? We gritted our teeth, hoped for the waders not to leak and braved the elements ...
Luckily, we were able to find a bed and a warm shower afterwards in the Alheim Commons of the Wells NERR. On the morning after, we walked into a frosty winter land, still somewhat incredulous that we actually went beachseining the night before. We believe that the drop in temperature has made the fish move to slightly deeper water that are not accessible via beachseine anymore. We learned something. Did we? But that's how science - sometimes - works.
Fishery Bulletin publishes black sea bass diet metabarcoding study
Posted on by Hannes Baumann
22 November 2024. We are happy to share that our paper on black sea bass stomach content metabarcoding has been published today in the traditional NOAA journal Fishery Bulletin. Our study used black sea bass juveniles caught in Mumford Cove to study their diet via a molecular approach known as metabarcoding. This method often detects rare or soft-bodied prey better than traditional morphological content analyses. We found that small, newly settled black sea bass eat mostly shrimp, but also many softbodied polychaetes. And weirdly, they seem to like one particular kind of (invasive) amphipod. Only larger juveniles seem to add fish to their diet.
Our study is a great first collaboration between our departments genomic experts (Ann Bucklin, Paola Batta-Lona) and the Evolutionary Fish Ecology Lab. The first product of our collaborative efforts has seen the light!
Fishery Bulletin is the 143 years old peer-reviewed journal managed and published by the National Marine Fisheries Service (NMFS) of the National Ocean and Atmospheric Administration (NOAA). It publishes Open Access at no costs to authors. Click the link below to download the paper.
- Batta-Lona, P.G., Wojcicki, M.L., Zavell, M.D., Bucklin, A., and Baumann, H. (2025)
Using DNA metabarcoding to reveal prey diversity in diets of juvenile black sea bass (Centropristis striata) in Long Island Sound in the Northwest Atlantic Ocean.
Fishery Bulletin 123:22-33
Trawling for sand lance at the Revolution offshore wind field
Posted on by Hannes Baumann
6 September 2024. During the first research cruise of the CIEROW group on board the R/V Connecticut, our lab deployed a box trawl in- and outside the Revolution Wind field for a total of 7 times and 5 different locations. The box trawl had a 6 mm cod-end and tickler chains to catch small benthic fish – specifically sand lance of the genus Ammodytes.
The box trawl was deployed from the main deck winch of the R/V Connecticut, with approximately 200m of wire let out in stations with water depths ranging from 34 – 38m, trawl speeds of 2 – 2.5kn for 13-15 upon reaching full wire-out lengths. Total trawl time (trawl in water – out of water) was about 25 minutes. During light hours, the trawl was equipped with a GoPro (Hero 4) to obtain footage of the trawled seafloor and potential organisms.
Overall, the trawl worked well with the ship and deployed as intended over the bottom. The GoPro footage revealed mostly sandy/muddy substrates with surprisingly little benthic fish life. Sand lance were neither caught in the trawl nor seen on the videos. Most trawls caught only few organisms, with the exception of Trawl 3 at station R6, which collected a number of common benthic fishes such as two hake species, one skate, sea robin and scup.
For this first deployment, we were cautious operating the gear in safe areas, but probably ended up trawling over sandy/muddy sediments that are not good habitat for sand lance. For the next cruise, we will therefore aim to alter trawl locations to include stations with known gravel or coarser sediment types.
A special thanks to Joel Llopiz and Lyndsey Lefebvre from Woods Hole Oceanographic Institution, who kindly lent us the box trawl to fish for sand lance, and to Justin Suca for facilitating this. We are also grateful to Marco, Sam, John and Luke from the R/V Connecticut crew for helping to deploy this new gear, even in somewhat rougher seas.
Welcome Home!
The first CIEROW cruise in the local UConn news:
UConn Today: UConn Researchers Set Sail for Wind Study
Daily Campus: UConn Avery Point researchers begin study on offshore wind farms and ocean habitats