Lab News

High CO2 tolerance of Black Sea Bass embryos / larvae – just out!

12 June 2024. We are excited to share that Environmental Biology of Fishes just published our study on the CO2 sensitivity of Black Sea Bass early life stages! The experimental work was part of Max Zavell's PhD-research and required the development of new approaches for obtaining spawning adults, new rearing methods, and new techniques for quantifying hatchlings and feeding larvae.

In the end, our research extends earlier experimental work to show that Black Sea Bass embryos and larvae are surprisingly tolerant to even extreme pCO2 conditions - which means that this species is likely resistant to the direct (!) effects of ocean acidification. Scientifically, this is intriguing because it points to some form of pre-adaptation that adults confer to their offspring in a manner we just don't understand yet.

Congrats, Max, to another chapter of your thesis published!


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Black Sea Bass early life stages, developing rapidly at 20C

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Hatching success of black sea bass embryo exposed to different pCO2 conditions (modified after Zavell & Baumann 2024)

A Day on the Ocean

20 May 2024. Who wouldn't want to trade the confines of a highschool classroom for a day on the ocean, particularly one packed with whales, dolphins and seabirds? On this Monday in May, 60 seniors of the Marine Magnet Highschool in Groton, CT and the Plainfield Highschool in Plainfield, CT were indeed lucky enough to enjoy such exceptional experience and a very special class out on the water.

Because this was no ordinary whale watch. Our team from the NSF-funded sand lance project (Hannes, Zosia, Lucas, and Emma) accompanied the highschoolers and together boarded the "Tails of the Sea" (Captain John Boats, Plymouth, MA). While the vessel navigated the route to the Stellwagen Bank National Marine Sanctuary, Zosia, Emma and Lucas assembled small groups of students to tell them more about what extraordinary fish sand lance are, why they are so important, and why ocean acidification may be a troublesome issue for these forage fish.

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On 20 May 2024, Emma Siegfried explains the importance of sandlance to highschool students

What we hoped but couldn't have known for sure: nature spectacularly cooperated with our curriculum. We observed large numbers of minke, fin, and humpback whales as well as a large pod of Atlantic white-sided dolphins chasing schools of sand lance all around the ship, while gannets, seagulls and terns were trying to get their share of the feast from above. Mesmerized, nobody could get away without learning the central lesson of this day. Sand lance are the backbone of the Stellwagen Bank National Marine Sanctuary, and there are still too many things we do not know about these fish.

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Lucas Jones introduces Stellwagen Bank to students of the Marine Magnet Highschool in Groton, CT

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Zosia teaching students from Plainfield Highschool about ocean acidification and potential impacts on the food web

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On May 20th 2024, students stand on the bow of the 'Tails of the Sea' to spot whales and dolphins

A special thanks for a flawless coordination and logistics to highschool teachers Amy Ferland from Groton, Stephanie Pye and Anita Japp (supporting this event despite her recent retirement) from Plainfield. This NSF-funded outreach activity will now be repeated for two more years! At least all our team can't wait to get out there again. Have a look at the days pictures and a video of some of the most memorable moments.

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Returning from a successful class two teachers from the Marine Magnet Highschool and UConn's Zosia Baumann

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Emma Siegfried, Lucas Jones, and Zosia Baumann

The new cod – WrackLines article on our Black Sea Bass research

28 May 2024. The latest issue of Wrack Lines, the in house magazine of Connecticut Sea Grant, just published a nice feature article about our recent and ongoing research on Black Sea Bass in Long Island Sound. Written by Paul Choiniere, the article explains the background and the research in an easy, accessible way, while introducing our lab and its main actors.

Have a read!
(downloads pdf)


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A strong showing at the 47th Larval Fish Conference!

17 May 2024. Members of our Evolutionary Fish Ecology Lab had a blast attending this years 47th Larval Fish Conference in Huron, OH. Hannes, Emma, Max and alumnus Chris Murray (now at WHOI), went on a road trip from Connecticut to Lake Eerie to present and learn about all things larval fish. On Tuesday morning, the conference crowd enjoyed excursion or recreation options, all the while catching up with good old colleagues and making new connections and friends. A particular achievement: each of us presented research on a different fish species; while Hannes showed the first data emerging from his sabbatical research on Chilean silversides, Emma talked about baby California grunion development. Max presented a poster and two talks, the first about CO2 effects on the onset of schooling in Atlantic silversides and a second one one Black Sea Bass overwintering dynamics. Last, Chris Murray gave a fascinating first look into gene expression data from our most recent sand lance CO2 experiment. All around, a strong showing of our lab!
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Contributions from our lab to the 47th Larval Fish Conference in Huron, OH

  • Baumann, H., Gallardo, A., Gallardo, C., and Urbina, M. 2024. First evidence for countergradient growth variation in the Chilean silverside Odontesthes regia. Oral presentation
  • Siegried, E. and Johnson, D. 2024. Eyes bigger than your stomach: developmental inaccuracy in larval California grunion. Oral presentation.
  • Zavell, M.D., Mouland, M., Barnum, D., Matassa, C., Schultz, E.T., and Baumann, H. 2024. Overwintering dynamics of northern stock Black Sea Bass, Centropristis striata, juveniles. Oral presentation.
  • Zavell, M.D., O'del, J., Mouland, M., Webb, J.F., and Baumann, H. 2024. Ontogeny of larval schooling and effects of ocean acidification in Atlantic Silversides (Menidia menidia). Oral presentation.
  • Murray, C.S., Jones, L., Siegfried, E., Zavell, M.D., Baumann, Z., Wiley, D., Therkildsen, N., Aluru, N., and Baumann, H. 2024. Examining the effect of ocean acidification on hatching enzyme gene expression in Northern sand lance (Ammodytes dubius). Oral presentation.

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Long-time attendees of the LFC happy to meet again (fltr: Pascal Sirois, Dominique Robert, Hannes Baumann, Chris Chambers, Bill Leggett)

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Proud members of the lab at the end of the LFC47

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Extensive fields of water lilies in the Huron River, OH

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A nice break from conference science, kayaking the Huron River

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A very relaxing morning with great weather

Max Zavell defends his PhD thesis!

 

18 April 2024. Today we are happy and proud to announce that Max Zavell has successfully defended his dissertation titled "Experimental assessment of ocean warming and acidification effects on multiple life stages of Black Sea Bass, Centropristis striata". A big, heartfelt congratulations from the entire lab!

Max Zavell had started as a PhD student in our lab in fall 2020, and his thesis research broke new ground by working experimentally with Black Sea Bass, a grouper species of great interest because of its recent, explosive increase in abundance in Long Island Sound and the larger northwest Atlantic shelf. Over two fall and winter seasons, Max conducted ambitious long-term rearing experiments on juveniles and adults to study how overwintering could be the key to understand these new dynamics. Now, after only three and a half years, Max has stepped up to the plate and showed his peers and colleagues the fruits of the work.

We were particularly delighted that all this committee members - Profs. Jacqueline Webb (URI), Catherine Matassa (UConn), and Eric Schultz (UConn) - were able to attend in person!

Well done, Max! Your team spirit and unwavering energy will be missed! We wish you all the best for your next career steps!

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On April 18th, Max begins presenting his PhD research at UConn's Department of Marine Sciences

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Done! Max and Hannes savor a moment of pride in the Rankin Lab

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Max Zavell and Matt Mouland, who were a great team in the Rankin Lab and beyond

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Max with Hannes and Prof. Jacqueline Webb from the University of Rhode Island

Hannes returns from Chile!

 

16 April 2024. After a 9-month sabbatical stay at the University of Concepcion in Chile, Hannes returned to US soil today, full of experiences, data, and a chest full of samples of larval, juvenile, and adult Chilean silversides. Grateful to the many helpful colleagues and friends, a first year of experiments are in the bag, resulting in a number of interesting findings that await further analysis and - crucially - a second, replicate experiment in the year to follow. In other words, while the sabbatical is now over - the project of revealing co- and countergradient variation in the Chilean silverside is still very much underway. On to the next chapter!

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The cove of Puda near Dichato to the north of Concepcion, Chile

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.



Fig03---Exp1-GRTL-SGR-Cons
(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!

UConn Today reports on Hannes’ Chile research

This article has been reposted from UConn Today. Read the original here

October 12, 2023 | Elaina Hancock - UConn Communications

Snap Shot: How Will Organisms Adapt to Climate Change?

A UConn Marine Sciences researcher is spending time in Chile studying an important forage fish, and how this vital part of the food chain will adapt to a changing climate

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The rocky and picturesque shores of the Pacific near Dichato

The world’s oceans have experienced record heat in 2023. With rising temperatures and increasing acidification, we don’t yet know the full extent these changes will have on marine ecosystems.

UConn Department of Marine Sciences Associate Professor Hannes Baumann studies fish, including important forage fishes such as sand lance and silverside, to see how they adapt to changes in environmental conditions. Many species are already adapted to temperature gradients that exist across latitudes on Earth, and Baumann believes that from these patterns, we can learn how fish may adapt to climate change – in time. This so-called “Space-for-Time” approach is one tool scientists use to predict the long-term consequences of climate change.

As part of his post-doctoral work, Baumann experimentally found similar climate adaptation patterns in Atlantic and Pacific silversides. He suspects that a higher-order relationship exists between the strength of adaptation and the strength of the underlying climate gradient.

Now, with a grant from the National Science Foundation, Baumann has the opportunity to return to and expand his study of silversides to a South Pacific species and study how they are adapted to their coastal latitudinal temperature gradient.

“We are hoping the prove the validity of a principle of evolutionary adaptation for the Southern Hemisphere. It will then allow us to compare and integrate the patterns with the silverside species from the Northern Hemisphere, which evolutionary ecologists have been studying for decades already,” says Baumann.

After a two-week proof-of-concept trip to Chile in the Fall of 2022, Baumann established connections with local fishermen and colleagues at the Universidad de Concepcion in Dichato, Chile.

“To get spawning fish, we visit fish markets – called here caletas de pescadores – and first establish a connection to those who make a living catching silversides (“pejerrey del mar”). We’re making friends to explain our unusual request to accompany a fisherman during the night. This is the best method to make sure that the eggs get fully fertilized," he says.

In the Summer of 2023, Baumann began his yearlong sabbatical and has now moved to Chile for five months to begin the main experimental work on Chilean silversides, their adaptations, and the strength of those adaptations to underlying climate change.

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Hannes in Tongoy near Coquimbo/Chile

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