Presentations

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

Feeling the pulse of Mumford Cove

23 March 2023. For almost 8 years now, the Evolutionary Fish Ecology Lab has conducted research in nearby Mumford Cove, a small, eelgrass covered embayment on eastern Long Island Sound. Using a set of battery-powered probes we have continuously measured temperature, pH, oxygen, salinity, and depth in 30 min intervals in the Cove - almost 120,000 times. This ongoing effort is not funded by any grant or institution; instead, it has been sustained over all these years by the firm belief in the prescient, if undervalued societal service of monitoring, an activity without short-term reward but important long-term benefits in understanding how ecosystems change on short and long time-scales. To commemorate the effort, we simply thought that it is time to show you some data, some pictures, and draw some early, cautious conclusions about the very interesting case of Mumford Cove. Have a look!

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Fig.1: Schematic section of the upper part of Mumford Cove, showing the deployed probe (blue) between the bottom anchor (grey) and a subsurface float (orange), marked by a surface float (white). The probe sits in the deepest part of the Cove (Channel), at constant 50 cm distance to the bottom, but variable water level above (red histogram).

"Future generations will certainly have better theories, tools, models, and computers, but they will still depend on the data and measurements taken here and now."

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Aerial view of Mumford Cove (Picture: Jamie Vaudrey)

Fishing for silversides … in Chile!

A two-week stint to south-central Chile ends with a successful proof-of-concept that planned research on a Chilean silverside species will be highly feasible, opening avenues for a budding US-Chilean collaboration.

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Fishing boats in Caleta Tumbes near Concepcion, Chile

Concepcion (Chile), 12 October 2022. Two incredible weeks of adventure and scientific exploration for new and potentially groundbreaking science are coming to a close. In preparation for next year’s sabbatical, Hannes has met and made friends with colleagues at the Universidad the Concepción in southern Chile, travelled some 2,000 miles along the stunning Chilean coast, scoured local fish markets and accompanied artisanal fishermen on their nightly pursuits. The goal: finding a small fish that looks all too familiar – a silverside!

The Chilean silverside (Odontesthes regia), locally known as ‘pejerrey’, looks eerily similar to the Atlantic silverside (Menidia menidia), the model that has already inspired decades of eco-evolutionary research across many labs including ours. And like its northern hemisphere cousin, Chilean silversides occur over an astounding geographical range along the South American Pacific coast, all the way from Puerto Montt (42°S) to southern Peru (10°S)! There, average coastal temperatures change predictably with latitude and therefore provide a natural climate gradient in space that could serve as an analogue to climate change in time. Whether and how Chilean silversides show similar local adaptations to their latitudinal gradient is a big question – and next year’s sabbatical will start to provide some important answers.

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Pejerrey are usually caught with gillnets as here in the picture

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A Chilean silverside embryo of a few days post fertilization. Eyes beginning to pigment and a prominent yolk artery provides nutrients for growth

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A Chilean silverside embryo close to hatch

To prepare, Hannes spent two weeks in September and October 2022 in Chile. Hosted by the ever-enthusiastic Prof. Mauricio Urbina from the zoology department and thanks to a visiting grant from the university, we were ready to start exploring. Our specific goal for this trip was to find spawning-ripe pejerrey in two of the planned four locations along the coast.

The luck was on our side and the timing of the visit turned out to be perfect. On a nightly fishing trip with the artisanal fisherman Juan Figueroa from the small village of Tumbes near Concepción, we caught running ripe males and females, observed naturally deposited egg masses in nearshore waters, and were able to subsequently document the temperature-dependent development of newly fertilized embryos.

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Left: During spawning season, pejerrey deposit enormous masses of eggs on vegetation in shallow water. Right: The Marine Station of the Universidad de Concepcion in Dichato

On an epic road-trip up the coast all the way to Coquimbo, Hannes and graduate student Rocio Barrios stopped at many villages and local fish markets, gathering information and finally securing precious samples of spawning-ripe pejerrey from a fisherman at the Coquimbo fish market. Transporting the embryos was a success, too, thereby paving the way for the proposed research plan next year.

The real, big common garden experiments will take place from September – December 2023 at the Dichato Marine Station near Concepción, a small but recently renovated station with excellent facilities for our purposes.

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On the road during our trip to Coquimbo

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Beautiful spring at the scenic Coliumo Bay near Concepcion

While at the University, Hannes also gave a seminar talk to the students and faculty explaining his excitement and plans for coming to Chile, which received great interest, curiosity, and students expressing interest to play a part in this.

    Baumann, H. 2022. Principles of local adaptation across environmental gradients (or: why I’m so darn interested in studying Chilean silversides). Invited seminar talk. University de Concepción, 29 Sep 2022

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A gillnet used to fish for Chilean silversides on the beach of Tumbes near Concepcion

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A newly hatched Chilean silverside measuring already an astounding 9 mm TL


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

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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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

Kelli Mosca presents Master thesis research on Atlantic Sturgeon

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21 March 2022. Today, Baumann lab graduate student Kelli Mosca presented her Masters thesis entitled "Atlantic sturgeon (Acipenser oxyrinchus) Growth and Habitat Use in the Connecticut River and Long Island Sound". She did a marvelous job summarizing the multifaceted findings on age and growth of Atlantic sturgeon in the eastern Long Island Sound and the Connecticut River, their movement patterns based on analyses of acoustic telemetry data, while evaluating the evidence for indications that Atlantic sturgeon may utilize the Connecticut River again for spawning.

Kelli was an inspirational and cherished member of the Baumann lab, who literally mastered the challenges of being a 'whole-pandemic' Master student. Her dedication and continued work for CTDEEP were awarded by an offer for a CTDEEP Fishery Biologist I position, which she has wholeheartedly accepted. Congratulations Kelli, and all the best for the next steps in your career!

The UConn Department of Marine Sciences
Presents a Master’s Thesis Presentation by

Kelli Mosca
B.S., University of New Haven, 2017

12:00 p.m., Monday, March 21, 2022
Lowell Weicker Building, Seminar Room 103 or Via WebEx

Atlantic sturgeon (Acipenser oxyrinchus) Growth and Habitat Use in the Connecticut River and Long Island Sound

Atlantic sturgeon (ATS, Acipenser oxyrinchus) are long-lived, anadromous, and endangered fish with a wide geographical distribution along the east coast of North America. Historically known to spawn in numerous rivers, many spawning runs ended due to intense fishing pressure and habitat obstruction in the 19th and 20th centuries. This was thought to be true for the longest river in the US Northeast, the Connecticut River, until pre-migratory ATS juveniles appeared in the river in 2014. Here, I use a long-term archive of fin spine samples and three years of acoustically tagged ATS to generally expand knowledge about the ATS using the CT River and LIS, and specifically examine these empirical data for potential evidence of re-emergent spawning behavior. I analyzed 301 sections of ATS fins spines collected from 1988-2021 to determine age, annuli widths, and thus population- and individual-based growth patterns. I found that the vast majority of ATS in my study area were juveniles and sub-adults with an average (± SD) age of 7.5 ± 3.1 years and an average (± SD) length of 101 ± 26 cm. The weighed, population-based Von Bertalanffy growth model estimated a K of 0.08 (95% CL, 0.01/0.17) and a L∞ of 171.2 cm (95% CI, 129/547 cm), the latter likely showing signs of missing large adults. K and L∞ distributions showed no sign of sex-specific multi-modality. Longitudinal length back-calculations revealed the selective disappearance of faster growing phenotypes (at ages 2-6) with increasing age at capture, which is clear evidence for Lee’s phenomenon. Acoustic detections of telemetered Atlantic sturgeon (2019-2021) revealed that most sturgeon in 2019 and 2020 utilized the Lower CT River (brackish water), whereas in 2021 detections were highest in LIS (salt water). Detections in the Upper CT River (freshwater) were common but much less dense across years, with 53%, 69% and 45% of ATS detected in the Upper CT River at some point in each season (2019-2021 respectively). I found a positive relationship of fish proportion in the CT River with temperature, but an inverse relationship of fish proportion in the CT River with river discharge. On average, the arrival of fish in the CT River occurred in June, when water temperatures were 17.5 - 24.9 ºC, while the departure from the CT River generally occurred in October, coinciding with river temperatures of 15.2 - 20.4 ºC. Some of the fish utilizing the Upper CT River made directed movements to a potential spawning ground at Portland, CT (river km 47). However, these movements occurred in mid- to late August (12th -23rd), which is inconsistent with the typical spring timing of ATS spawning runs in northern populations. Fall spawning runs are only known for southern ATS populations. In addition to timing, ATS sizes in the Upper CT River also do not support spawning behavior, because fish of all sizes (72 – 154 cm TL) and ages (3-15) visited the Portland area for 0.25 – 63.25 days. I conclude that neither age nor telemetry data support the re-emergence of the CT River as an ATS spawning ground. Future work will benefit from a more even sampling of gear sizes and should examine possible explanations for ATS freshwater utilization including feeding and individual preferences.

Major Advisor: Hannes Baumann
Associate Advisor: Eric Schultz
Associate Advisor: Tom Savoy
Associate Advisor: Jacque Benway
Associate Advisor: Catherine Matassa

Hannes gives DMS Friday seminar on sand lance ecology

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.


Video: A November day on Stellwagen Bank

Lucas Jones presents his Masters Thesis research!

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Lucas and Hannes celebrating the successful thesis presentation

Monday, November 22nd 2021. Big and heartfelt congratulations to Lucas Jones, who presented his Master thesis to his peers at the institute and colleagues national and international. Well done, Lucas!

A link to his recorded presentation will be posted here soon.


The UConn Department of Marine Sciences

Presents a Master’s Thesis Presentation by

Lucas Jones

B.A., University of Connecticut, 2018

4:00 p.m., Monday, November 22, 2021

Marine Sciences Building, Seminar Room 103

 

Using Low-Coverage, Whole Genome Sequencing to Study Northern Sand Lance (Ammodytes dubius) Population Connectivity in the Northwest Atlantic

 Northern sand lance (Ammodytes dubius) are key forage fish in Northwest Atlantic (NWA) shelf ecosystems, where they exclusively occur on coarse-grain, offshore sand banks. This patchy occurrence may result in genetically more fragmented, less connected populations, but traditional morphological or genomic approaches have so far been unsuccessful in fully resolving the species’ population structure and connectivity. My study pursued an alternative genomic approach, using low-coverage, whole genome sequencing (LcWGS) to address these important questions. I extracted DNA from 273 A.dubius specimens collected by collaborators from sevenregions across the species geographical range, from Greenland to New Jersey, USA. From LcWGS data, I identified 11,558,126 single nucleotide polymorphisms (SNPs) that allowed quantifying genetic differentiation between populations (FST), thereby revealing the genetic structuring of populations throughout the NWA. Despite the potentially homogenizing influence of the general north to south ocean circulation, I found a clear genetic break around Nova Scotia that delineated a northern from a southern A. dubius supergroup. Only within the southern supergroup, genetic distances increased with the geographic distance between sample sites. At the focal site of Stellwagen Bank (southern Gulf of Maine), A. dubius samples collected over several years (2014 – 2019) revealed small but significant temporal genetic differences that imply varying occupation of this offshore habitat by genetically different sand lance contingents. Inclusion of samples from the inshore congener A. americanus confirmed the clear genetic separation between both species and further determined that all sand lance caught on Stellwagen Bank are exclusively A. dubius. Overall, my work suggests the existence of two spatially distinct A. dubius populations with little ‘realized’ connectivity, which is critical knowledge to aid protection and management of offshore marine resources.

 

Major Advisor:                   Hannes Baumann

Associate Advisor:            Nina Overgaard Therkildsen

Associate Advisor:            Senjie Lin