Author: Hannes Baumann

Trawling for sand lance at the Revolution offshore wind field

Posted on September 11, 2024September 13, 2024 by Hannes Baumann

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.

Fishing for inshore sand lance in Maine

Posted on September 11, 2024September 11, 2024 by Hannes Baumann

20 August 2024. Emma and Hannes went on a road trip through New England to again visit our good friends and colleagues at the National Estuarine Research Reserve (NERR) in Wells, ME, Jeremy Miller and Jason Goldstein. Our mission this time was to try - for the first time - to find and collect American sand lance (Ammodytes americanus), the congener species to the Northern sand lance (A. dubius), which our lab has been investigating for now more than 7 years.

While the Northern sand lance can be reliably found on Stellwagen Bank in the southern Gulf of Maine, the specific whereabouts and promising collection sites for A. americanus are new, uncharted territory for us. They are often referred to as the inshore sand lance species, but where exactly would be a good spot to collect them?

On this late August week, we followed a tip from Jeremy from the Wells NERR to look at the harbor, where he had seen large schools near the docks all through summer.

After a good amount of scouting and trial (and error!) we ultimately got lucky at dead low tide, where we were able to use the beach seine to catch more than a thousand sand lance adults and eventually succeeded in transporting ~ 300 of them back to the Rankin Lab for further learning how to rear and keep them.

This was the first of a handful of upcoming trips, where we plan to catch sand lance closer and closer to the begin of their spawning season at the end of November.

We hope that the luck stays with us during the next trips.

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

Posted on June 13, 2024June 13, 2024 by Hannes Baumann

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!

A Day on the Ocean

Posted on June 6, 2024June 6, 2024 by Hannes Baumann

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.

Emma and students — 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.

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

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

Posted on May 28, 2024May 28, 2024 by Hannes Baumann

A strong showing at the 47th Larval Fish Conference!

Posted on May 18, 2024May 18, 2024 by Hannes Baumann

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!

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.

Max Zavell defends his PhD thesis!

Posted on April 21, 2024April 23, 2024 by Hannes Baumann

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!

Hannes returns from Chile!

Posted on April 21, 2024April 21, 2024 by Hannes Baumann

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!

TAFS publishes our first Black Sea Bass experiment paper!

Posted on December 28, 2023December 28, 2023 by Hannes Baumann

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.

New 2023 sand lance experiment under way!

Posted on November 27, 2023November 27, 2023 by Hannes Baumann

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.