[Lab news] Adult black sea bass arrive at UConn’s Rankin lab

Establishing a Black Sea Bass brood stock to study early life history effects of warming and acidification

Max Zavell

December 2020. We are happy to announce that as of a few weeks, we are now housing two brood stock populations of Black Sea Bass (Centropristis striata) at UConn's Department of Marine Sciences Rankin Seawater Lab. The adults will be reared for the next few months under contrasting CO2 regimes in 1000gal tanks each. After photoperiod manipulation and hormone-injection we plan to strip-spawn adult fish and test their offspring for their CO2 and temperature sensitivity. Black Sea Bass are rapidly increasing in abundance in New England Water and the Gulf of Maine, but research on early life stages is still lacking. PhD student Max Zavell meticulously taking care of these fish now.


Catch a glimpse of these beautiful animals below

JEB publishes paper on metabolic effects of high CO2 in silverside embryos! [New publication]

19 November 2020. We are happy to announce that the Journal of Experimental Biology just published the latest paper on CO2 effects in the early life stages of Atlantic silversides! For her PhD research at Stony Brook University, Teresa meticulously measured oxygen consumption in developing silverside embryos and newly hatched larvae exposed to contrasting oxygen and CO2 conditions throughout multiple experiments in 2017 and 2018. Her work shows that the metabolism of embryos but not larvae is sensitive to elevated CO2 conditions, leading to higher metabolic rates at normoxic levels, but reduced metabolic rates under low oxygen conditions, compared to controls. These basic empirical data confirm the emerging picture that CO2 effects in marine fish manifest largely if at all during early ontogeny, i.e., during the embryo stages. Well done, Teresa, and congratulations to your first lead-author paper!
Conceptual diagram of the relationship between PO2 and RMR of M. menidia embryos in ambient and elevated PCO2. Hypothesized shifts in the relationship between embryonic RMR and PO2 are shown for elevated (orange) versus ambient (blue) PCO2. Our results (measured at the PO2 levels marked by black dots) suggest that PCO2 can influence both the critical oxygen partial pressure (Pcrit, gray lines) and the oxygen-independent RMR. At higher PO2 levels, RMR increases with PCO2, potentially owing to increased metabolic demand. As PO2 decreases, embryonic RMR reaches Pcrit and becomes oxygen dependent at a higher PO2 level in acidified than in ambient PCO2 conditions. Low intracellular red blood cell pH caused by high PCO2 can be expected to reduce hemoglobin–O2 affinity (Bohr effect) and make embryonic RMR less hypoxia resistant, which could manifest as an increase in Pcrit for embryos in elevated PCO2.

Welcome to Max Zavell & David Riser [Lab News]

Max Zavell | David Riser

31 August 2020. The Baumann Lab is growing again and happy to welcome Max Zavell and David Riser as new graduate students to our lab!

Max Zavell just started on his journey as a PhD student in fall 2020, after graduating the same May with his Bachelor from the University of Rhode Island. Max is interested to work experimentally and continue exploring questions of coastal fish and climate change. In addition to continue working with Atlantic Silverside (Menidia menidia), his work will break new ground for our lab by starting with a new species for in our lab: Black Sea Bass (Centropristis striata). Growth and physiology of this northernmost grouper species is of interest, given its recent, explosive increase in abundance in Long Island Sound.

David Riser started his Masters in September 2020 after graduating with his Bachelor from the University of Connecticut and a Major in Marine Sciences. David already looks back on a successful career in the US Coast Guard, but now ventures to develop academic chops and expertise. In close collaboration with CTDEEP, he will analyze time series of Black Sea Bass catches in Long Island Sound and begin collecting and aging adult Black Sea Bass using otoliths.

Welcome from all of us!

On 12 September 2017, a juvenile Black Sea Bass (Centropristis striata) sits in nearshore waters of Long Island Sound, while a school of Atlantic silverside juveniles passes by (Jacob Snyder, Bluff Point)

Baby sturgeon in the Connecticut River!


Juvenile Atlantic sturgeon caught in June 2020 in the Connecticut River (photo: Jacque Benway, CTDEEP)

By Kelli Mosca.
3 July 2020. Atlantic sturgeon (Acipenser oxyrinchus) is an endangered, long-lived, anadromous fish that is found along the North American coast from the St. Lawrence River (Canada) to the St. John’s River (Florida). Historically, Atlantic sturgeon spawned in the Connecticut River, but until recently spawning populations were thought to be extirpated. In June 2020, a small, very young and therefore likely pre-migratory specimen (253mm) was captured by CTDEEP in the Connecticut River (above). This discovery is only the second after the first occurrence of small sturgeon in 2014! Together, this may be the beginning of a small Atlantic Sturgeon population rediscovering their long-lost spawning ground in the Connecticut River. CTDEEP and the Baumann Lab are working to find more fish of this size- and year class, and answer related questions about surgeon age and size and migration patterns. (CT SeaGrant project)

[New publication] PLOS One publishes long-term silverside growth study!

27 July 2020. Big and proud congratulations to Chris Murray, who published his last big chunk of data from his PhD research on the effects of marine climate change on coastal marine fish. The publication in PLOS One synthesized 3 years of multiple, long-term experiments on Atlantic silversides (Menidia menidia) demonstrating consistent negative growth effects on high CO2 conditions. However, sometimes it takes more than just looking at means and standard deviations to elucidate these effects. Hence, in this paper, shift functions analyzing the different percentiles of distributions are employed.

Murray, C.S. and Baumann, H. (2020) Are long-term growth responses to elevated pCO2 sex-specific in fish? PLOS One 15:e0235817

The publication was featured in UConn Today “UConn Research: More Carbon in the Ocean Can Lead to Smaller Fish

By Elaina Hancock

As humans continue to send large quantities of carbon into the atmosphere, much of that carbon is absorbed by the ocean, and UConn researchers have found high CO2 concentrations in water can make fish grow smaller.

Researchers Christopher Murray PhD ’19, now at the University of Washington, and UConn Associate Professor of Marine Sciences Hannes Baumann have published their findings in the Public Library of Science (PLoS One).

“The ocean takes up quite a bit of CO2. Estimates are that it takes up about one-third to one-half of all CO2 emissions to date,” says Murray. “It does a fantastic job of buffering the atmosphere but the consequence is ocean acidification.”

Life relies on chemical reactions and even a slight change in pH can impede the normal physiological functions of some marine organisms; therefore, the ocean’s buffering effect may be good for land-dwellers, but not so good for ocean inhabitants.

Baumann explains that in the study of ocean acidification (or OA), researchers have tended to assume fish are too mobile and tolerant of heightened CO2 levels to be adversely impacted.

“Fish are really active, robust animals with fantastic acid/base regulatory capacity,” says Murray. “So when OA was emerging as a major ocean stressor, the assumption was that fish are going to be OK, [since] they are not like bivalves or sea urchins or some of the other animals showing early sensitivities.”

The research needed for drawing such conclusions requires long-term studies that measure potential differences between test conditions. With fish, this is no easy task, says Baumann, largely due to logistical difficulties in rearing fish in laboratory settings.

“For instance, many previous experiments may not have seen the adverse effects on fish growth, because they incidentally have given fish larvae too much food. This is often done to keep these fragile little larvae alive, but the problem is that fish may eat their way out of trouble — they overcompensate – so you come away from your experiment thinking that fish growth is no different under future ocean conditions,” says Baumann.

In other words, if fish are consuming more calories because their bodies are working harder to cope with stressors like high CO2 levels, a large food ration would mask any growth deficits.

Additionally, previous studies that concluded fish are not impacted by high CO2 levels involved long-lived species of commercial interest. Baumann and Murray overcame this hurdle by using a small, shorter-lived fish called the Atlantic silverside so they could study the fish across its life cycle. They conducted several independent experiments over the course of three years. The fish were reared under controlled conditions from the moment the eggs were fertilized until they were about 4 months old to see if there were cumulative effects of living in higher CO2 conditions.

Murray explains, “We tested two CO2 levels, present-day levels and the maximum level of CO2 we would see in the ocean in 300 years under a worst-case emissions scenario. The caveat to that is that silversides spawn and develop as larvae and early juveniles in coastal systems that are prone to biochemical swings in CO2 and therefore the fish are well-adapted to these swings.”

The maximum CO2 level applied in the experiments is one aspect that makes this research novel, says Murray,

“That is another important difference between our study and other studies that focus on long-term effects; almost all studies to date have used a lower CO2 level that corresponds with predictions for the global ocean at the end of this century, while we applied this maximum level. So it is not surprising that other studies that used longer-lived animals during relatively short durations have not really found any effects. We used levels that are relevant for the environment where our experimental species actually occurs.”

Baumann and Murray hypothesized that there would be small, yet cumulative, effects to measure. They also expected fish living in sub-ideal temperatures would experience more stress related to the high CO2 concentrations and that female fish would experience the greatest growth deficits.

The researchers also used the opportunity to study if there were sex-determination impacts on the population in the varying CO2 conditions. Sex-determination in Atlantic silversides depends on temperature, but the influence of seawater pH is unknown. In some freshwater fish, low pH conditions produce more males in the population. However, they did not find any evidence of the high CO2 levels impacting sex differentiation in the population. And the growth males and females appeared to be equally affected by high CO2.

“What we found is a pretty consistent response in that if you rear these fish under ideal conditions and feed them pretty controlled amounts of food, not over-feeding them, high CO2 conditions do reduce their growth in measurable amounts,” says Murray.

They found a growth deficit of between five and ten percent, which Murray says amounts to only a few millimeters overall, but the results are consistent. The fish living at less ideal temperatures and more CO2 experienced greater reductions in growth.

Murray concludes that by addressing potential shortcomings of previous studies, the data are clear: “Previous studies have probably underestimated the effects on fish growth. What our paper is demonstrating is that indeed if you expose these fish to high CO2 for a significant part of their life cycle, there is a measurable reduction in their growth. This is the most important finding of the paper.”

This work was funded by the National Science Foundation grant number OCE #1536165. You can follow the researchers on Twitter @baumannlab1 and @CMurray187.

[Lab news] Hannes & colleagues organize a Virtual Town Hall

23 June 2020. It’s been a remarkable day. A remarkable few months of preparation. But on this Tuesday in June, more than 250 people from all over the world logged in to a UConn WebEx Event organized by Hannes Baumann, Eric Schultz, Jacqueline Webb, Paul Anderson and Jon Hare. The event, billed as the “1st Virtual Larval Fish Science Town Hall” was of course a product of the strange and challenging times we live in right now. A consequence of almost a year of painstaking preparations for the 44th Larval Fish Conference in Mystic, CT … eclipsed by the COVID-19 pandemic that made having a physical science conference impossible.

Number of attendees per minute throughout the day. Science sessions were followed by 120-170 attendees worldwide.
Network Mentors

The Virtual Town Hall gave 16 speakers from around the world the opportunity to communicate their science, while providing a forum for the community to interact. The Early Career Committee of the AFS Early Life History Section contributed as well, organizing a round table discussion led by Kelsey Swieca with Chris Chambers, Jackie Webb, and Peter Konstantidinis. Individual networking meetings – although hobbled initially by technology – were held after the meeting between senior and early career researchers.

And best of all – more than 40 people participated in a picture contest, contributing stunning images of larval fish or larval fish science.

For more information, speaker bios’s, talk titles, abstracts and even some video please visit the event website

Some of our personal favorites among the best larval fish picture submissions

Mike Bartick | Ribbon fish
Irene Middleton | A diver checks out a juvenile flying fish at the Poor Knights Islands in New Zealand
Suzan Meldonian | Cyclopsetta fimbriata, photographed in situ along Gulf Stream Current, SE Florida
Winner – Kerryn Parkinson | Mola sp – a larval sunfish collected off New South Wales, Australia.
Gabriel Monteiro | Caulolatilus chrysops larvae cleared and stained. This specimen belongs to ColBIO USP biological collection.
Harvey Walsh | Bothus larvae sorted at sea from a bongo net tow collected during the summer of 2017 aboard the NOAA Ship Gordon Gunter.
Chris Murray | Wild Pacific herring spawn from Skagit Bay, WA (~72 h old). Note the flat edge of the egg where it was adhered to sea grass.
Henrique Grande | Post-larval reef fish Acanthurus coeruleus Bloch & Schneider, 1801 collected in 2015 using light traps in the Bay of Tamandaré, Brazil.

[Lab news] Hannes gets promoted to Associate Professor

29 April 2020. Despite the lockdown and the virus, this is a joyful day for the Baumann lab – an unassumingly delivered note from the Provost – and both the end of a chapter and the beginning of a new era of Life and Science.

I’m grateful to so many people who aided this path along the way. Zosia, the boys, family, friends, and the many scientific mentors along the way.

This is a truly good day, not belittling the crisis & death all around us.



[New Publication] Fish and Fisheries publishes review of sand lance!

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.

SL beam trawl_credit HB
Sand lance caught on Stellwagen Bank in November 2014

The publication of this article was featured by UConn Today on 24 March 2020.

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.

Staudinger, M., Goyert, H., Suca, J., Coleman, K., Welch, L., Llopiz, J., Wiley, D., Altman, I., Applegate, A., Auster, P., Baumann, H., Beaty, J., Boelke, D., Kaufman, L., Loring, P., Moxley, J., Paton, S., Powers, K., Richardson, D.E., Robbins, J., Runge, J., Smith, B.E., Spiegel, C., and Steinmetz, H. (2020)
The role of sand lances (Ammodytes sp.) in the Northwest Atlantic Ecosystem: a synthesis of current knowledge with implications for conservation and management
Fish and Fisheries (published online 20 March 2020)

[New Project] CTDEEP is funding our Atlantic sturgeon proposal!

1 Feb 2020. We are elated to announce that Connecticut Sea Grant has decided to fund our latest research proposal to study Atlantic sturgeon in Long Island Sound and the Connecticut River! The project is funded for two years under the most recent Omnibus Funding call and will examine the growth and seasonal movement of these magnificent, ancient fish.
Kelli Mosca
The project will fund the Master thesis research of Kelli Mosca, the most recent addition to our lab! After receiving her Bachelors degree from the University of New Haven, Kelli became a dedicated seasonal worker at the Connecticut Department of Energy and Environmental Protection (CTDEEP), where she assisted particularly with the sturgeon monitoring program. This has made her the best possible graduate candidate to work this project. Welcome, Kelli!

To learn more, head over to the project page.

Baumann, H., Savoy, T., Benway, J., and Pacileo, D. 2020. A re-emergent spawning population of Atlantic Sturgeon in the Connecticut River? Combined age analyses and telemetry data will provide new insights. Connecticut Sea Grant Program (NOAA) #R/LR-29, Feb 2020 - Feb 2022 ($150,000)


[Lab news] Hannes and Lucas on a ‘genetic’ road trip

18 December 2019. Hannes and Lucas just returned from a spontaneous road trip to visit our good friends and collaborators at the University of Quebec in Rimouski (UQAR), Canada. We drove for over 10 hours (one-way) through snowstorms and icy voids to meet with Prof. Dominique Robert, who had collected sand lance samples from the Gulf of St. Lawrence and from Nova Scotia to be included in our new genomic study on the population connectivity of this species. Hannes gave a talk about our sand lance work and we saw a new institute in a new place, while frantically trying to stay warm amidst the brutal cold. Seeing the St. Lawrence in its icy, majestic beauty was a truly amazing experience.
Afterwards, we drove back through Maine and then repeated the fin-clipping of samples in Scituate at the Stellwagen Bank National Marine Sanctuary office, so we now have almost all samples in hand to start the DNA extraction and sequencing.
We are excited for the next steps!

Sand lance samples to be included in the genomic study


Rimouski on the south shore of the mighty and icy St. Lawrence River on 12/13/19


Lucas and Hannes listened to Corinne Burns talking about her PhD research at UQAR on 16 Dec 2019


Hannes gave a talk about sand lance research at UConn


The icy beauty of the St. Lawrence River


Sun glistening on the ice on the banks of the St. Lawrence River on 16 Dec 2019


Snow storm on the I91 in Vermont on 15 Dec 2019


Driving back through Maine on 17 Dec 2019 ... 6h of snowstorm


Sand lance sample thawing to be fin-clipped


Hannes and Lucas fin-clipping specimens in the Stellwagen Bank NMS office in Scituate on 18 Dec 2019