Author: Hannes Baumann

[Field work] Beachseining from the fish perspective

Posted on September 26, 2015September 27, 2015 by Hannes Baumann

On this golden-crisp early fall Friday morning (9-25-15), we went to our favorite spot again – Mumford Cove – to go beach seining. Thanks to the many helping hands – Chris, Jake, Elizabeth, Wes, Megan, and Hannes – we hand a ton of fun, while seeing a very diverse catch, among of course our target species – Atlantic silverside juveniles. These were measured on the beach and then preserved, and will ultimately become part of a larger study of the seasonal characteristics of survivors.

However, have you ever wondered what it must be like for fish to get caught in a beach seine. Well, thanks to Jake’s new GoPro and his ingenuity tethering it to the bag of the seine, here’s a glimpse (in HD). Enjoy!

Measuring and weighing the beach seine catch (f.l.t.r: Wes, Elizabeth, Megan, Jake, Chris)

A juvenile Northern Kingfish, Menticirrhus saxatilis

Juvenile Winterflounder Pseudopleuronectes americanus

Elizabeth and Chris seining the Mumford Cove beach

[Lab News] Laboratory silversides “becoming famous”!

Posted on September 16, 2015July 14, 2016 by Hannes Baumann

Sampling day! On September 15th 2015, our lab concluded a long-term growth experiment on four large laboratory populations (500+ fish per tank) of Atlantic silversides (Menidia menidia), which were reared at ambient and high CO2 levels and low temperature (17C) and feeding conditions. Given all the hard work rearing these fish from eggs to 4 month old juveniles, sacrificing them is always a bittersweet moment. To avoid the word ‘killing’, we therefore coined the euphemism “becoming famous”.

Thanks to Jake’s new GoPro, here’s a time lapse of all of us working for hours to sample, measure and preserve various parts of the populations for later analyses of weight, sex, as well as genetic and transcriptomic approaches.

Chris Murray measuring juvenile Atlantic silversides that were reared in our lab for the past four months

Fish measurement party — Some fish were measured immediately, others were preserved in formaldehyde/seawater solution, frozen at -20C or -80C

Hannes Baumann measuring some the many fish that were sampled on 15 Sep 2015 — Hannes measuring some the many fish that were sampled on 15 Sep 2015.

[Lab news] A summer research experience in the Baumann lab

Posted on September 10, 2015September 10, 2015 by Hannes Baumann

Chris & Molly are measuring silverside adults used to fertilize the first experiment …

By Molly Hughes

This summer, I was lucky enough to work in the Rankin Lab at Avery Point. I’d been looking for an opportunity to gain lab and field experience in marine biology, particularly in fish ecology and hypoxia research. I could not have had a better experience than volunteering with Hannes Baumann and Chris Murray this summer. Their research combines issues of hypoxia, ocean acidification and fish ecology to give meaningful insight into the range of effects possible under a changing climate.

Volunteering in the lab, I was able to develop practical skills in fish biology that are already coming in handy in my upper level Ichthyology course. In the field, I learned how to use a seining net to catch specimens and identify target species. In the lab I participated in spawning fish, fertilizing eggs and day to day maintenance of larval fish and their environment.

However, just as valuable as practical skills is the perspective I gained from this experience. Before volunteering at the Rankin lab, I’d never considered the importance of creative thinking in research. When Hannes and Chris set out to study the combined effects of pH and oxygen levels on larval fish development, there was no starter kit available for them to do so. They had to create an entirely novel system, and only through resourcefulness and a lot of trial and error were they able to make their idea a reality. For me this meant days of drilling holes in five gallon buckets and hot gluing mesh over them. This was a creative solution to the problem of continuous water flow between the buckets within a tank. Its a comfort to know that my arts and crafts skills have relevance to my aspirations in marine biology.

I also walked away from this summer with an appreciation of the interconnectivity of the sciences and the importance of collaboration. When a fungal pathogen wiped out most of the larvae in the first trial of the Hypoxia/Acidification experiment, we were not equipped to identify it. Neither Hannes nor Chris specialize in mycology, but they were able to reach out to colleagues at Avery Point and Stony Brook who do. This is just one example of the many times I saw Chris and Hannes collaborate with scientists and engineers of different specialties this summer.
This being my first experience in a research environment, I was very fortunate to volunteer in a lab where I was able to gain such a wide range of skills and knowledge. I’m grateful to Hannes and Chris for introducing me to the research world and giving me the confidence to keep pursuing a career in marine biology.

[Publication] Growth and mortality in coastal populations of Winter Flounder: implications for recovery of a depleted population

Posted on July 23, 2015January 28, 2016 by Hannes Baumann

This study by Yencho et al. examined growth, mortality, and settlement distributions of juvenile Winter Flounder Pseudopleuronectes americanus in two bays of Long Island, New York, to better understand localized population dynamics of a species experiencing a protracted population decline. They found that settlement distributions had multiple peaks (cohorts) occurring between March and late July in 2007 and between February and May in 2008. Otolith-based growth rate was significantly higher for Port Jefferson Harbor during 2007 than for all other year × location combinations. Together with previous research the finding of multiple spawning cohorts in Long Island Winter Flounder suggests a degree of isolation, and local management will be needed to support healthy populations.

Yencho, M.A, Jordaan, A., Cerrato, R.M., Baumann, H., and Frisk, M.G. (2015) Growth and mortality in coastal populations of Winter Flounder: implications for recovery of a depleted population.
Marine and Coastal Fisheries 7: 246-259.

[Presentation] Additive & synergistic effects of concurrent acidification and hypoxia on early life stages of three coastal forage fish

Posted on July 23, 2015July 14, 2016 by Hannes Baumann

39th Annual Larval Fish Conference, Vienna (Austria) 16 July 2015; American Fisheries Society Annual Meeting, Portland (OR), 19 August 2015

H. Baumann presented the Master thesis work of Elizabeth Depasquale about individual and concurrent effects of low pH and low oxygen conditions on larval forage fish species at two international conferences. The talk highlighted the novel findings of the study, i.e.: (1) that sensitivities to combined stressors are species- and trait-specific, (2), that larval fish overall seem to be less tolerant of low oxygen than low pH condition, but that (3) the combined effects can be additive and even synergistic; hence suggesting that focussing only on hypoxia in urbanized, eutrophied coastal waters may considerably underestimate the negative effects on larval fish. Even though hypoxia and acidification are almost always coupled conditions in marine environments, the empirical database on such multistressor experiments is still very small and thus precludes robust conclusions and generalizations across taxa or ecosystems.

Depasquale, E., Baumann, H., and Gobler, C.J. (2015) Variation in early life stage vulnerability among Northwest Atlantic estuarine forage fish to ocean acidification and low oxygen. Marine Ecology Progress Series 523: 145–156

[Publication] Comparing different growth proxies in young juvenile sprat

Posted on June 26, 2015July 12, 2015 by Hannes Baumann

Reliable estimates of short- and longer-term in situ growth and condition of organisms are critical if one hopes to understand how the environment regulates survival. This laboratory study reports the first comparison of somatic- (K), biochemical- (RNA–DNA ratio, RD) and otolith- (increment widths, OIW) based indices of condition of a young juvenile fish. It found that RNA:DNA ratios react 2x faster to growth changes due to changes in feeding level than otolith increment widths, while condition factor was the most variable proxy.

Peck, M. A., H. Baumann, C. Clemmesen, J. P. Herrmann, M. Moyano, and A. Temming 2015. Calibrating and comparing somatic-, nucleic acid-, and otolith-based indicators of growth and condition in young juvenile European sprat (Sprattus sprattus). Journal of Experimental Marine Biology and Ecology 471:217-228.

[Presentation] H. Baumann talks at the 3rd Ocean Acidification PI Meeting in Woods Hole, MA

Posted on June 12, 2015July 14, 2016 by Hannes Baumann

“Plastic and evolutionary responses to ocean acidification: navigating the difficult terrain between unfounded pessimism, optimism, and impossible tasks”

Woods Hole Oceanographic Institution, 11 June 2015

Experiments on contemporary marine organisms have demonstrated many negative responses to elevated CO2 levels, i.e., conditions that could occur in the average open ocean within the next 300 years. This has led to the recognition of ocean acidification (OA) as a key anthropogenic stressor and to concerns about detrimental changes to marine ecosystems on which humans depend. While assessing species sensitivities to OA has been the necessary first step, the gradual nature of these shifts further demands that we assess how transgenerational plasticity and evolutionary adaptation to OA will likely affect the overall vulnerability of species and ecosystems. Our predictive ability of these adaptive processes is still in its infancy.

Plastic & evolutionary responses to ocean acidification

The overview talk first looked at currently employed approaches to study adaptation, from relatively well-documented in vitro evolution to OA in single cell organisms to necessarily more inferential techniques (e.g., evolutionary potential, standing genetic variation, molecular techniques) in longer-lived metazoans where multi-generational experiments are largely unfeasible. Secondly, the talk touched on the likely role of transgenerational plasticity in mitigating adverse OA effects over shorter time-scales in some species and whether this could perhaps compromise their ability to genetically adapt. The final objective was to pose a number of largely unresolved questions (e.g., selection differentials? Evolutionary trade-offs?) and highlight a few, perhaps underutilized approaches (e.g., studying spatial gradients as analogies to temporal change) that might improve understanding of evolution and plasticity to OA.

The talk is publicly accessible on Prezi

[Lab News] Seining in Mumford Cove

Posted on June 8, 2015July 14, 2016 by Hannes Baumann

Here are some pictures from one of our first beach seining trips to Mumford Cove, CT (16 May 2015)

Seining and water sampling in Mumford Cove, CT

Hannes and Chris in Mumford Cove, discussing how to sort the catch of silversides collected by beach seine

Male and female silverside are separated and transported to our laboratory facility (Rankin Lab, UConn)

Sorting the catch of the beach seine, Mumford Cove 16 May 2015

[Lab News] Our new rearing system is operational!

Posted on June 5, 2015June 6, 2015 by Hannes Baumann

– The maiden voyage –
Although it still lacks a proper name, our experimental system to rear larval fish under different temperature, CO2, and oxygen conditions has finally started it’s first real trial with newly fertilized silverside embryos. The system consists of 9 independent units to allow any factorial 3 x 3 combination of rearing conditions. Each unit has a sealed main tank (400L) in which up to six individual rearing containers (20L) can be placed. Water samples from each unit are sequentially pumped past two wall-mounted oxygen and pH sensors, which feed their data into a computer program called LabView (NI), which in turn triggers solenoid valves to add CO2, nitrogen, or air to each system. Although straightforward in principle, the practice of putting all of this together is definitely more complicated and the devil in the detail. All told, the construction took us ~ 8 months, but we hope to be using this system for years from now.

Thumbs up to the many, many persons that were instrumental to the success of this; Paul Grecay and Timothy Targett (University of Delaware) for giving us the crucial inspiration about the general design of a system like that. Gary Grenier and Bob Dziomba from the machine shop for building the big pieces and thinking ahead of details that we certainly would have missed. Charlie Woods for his excellent help and assistance in the Rankin Lab, from plumbing to electrical to simply cheering us up. Dennis Arbige for taking on the tedious wiring of the solenoids without blinking an eye. Finally, many thanks to John Hamilton who’s excellent knowledge of LabView and great teaching skills helped Chris to become a LabView wiz in a matter of weeks!

Ready. Set. Go!

[Lab News] David Conover visits Avery Point and our lab

Posted on May 8, 2015July 14, 2016 by Hannes Baumann

A search party for Atlantic Silverside eggs. Dr. Conover visited our lab and in the morning hours of May 8th joined us in trying to find spawned silverside eggs in the intertidal zone of Mumford Cove.

On Friday morning, a little search party crossed Bluff Point Park in the hazy morning hours. Hannes, Chris (+bear), Jake and our guest, David Conover from Stony Brook University, set out to find eggs of Atlantic silversides in the intertidal zone of Mumford Cove. Dr. Conover explained, how and where to look, while the fog slowly got burned off and a gorgeous spring day began. Later, Dr. Conover gave a Friday seminar at the Marine Sciences Department titled: “Crisis in the Funding of Basic Research in the Ocean Sciences: An Inside Perspective on NSF and the Role of the Community”. Thank you for your visit, David!

New Spartina shoots at Mumford Cove on May 8th 2015