Author: Hannes Baumann

[Publication] Comparing different growth proxies in young juvenile sprat

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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 et al study

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

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“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

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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
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
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)
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
Sorting the catch of the beach seine, Mumford Cove 16 May 2015
Seining in Mumford Cove, CT
Seining in Mumford Cove, CT

[Lab News] Our new rearing system is operational!

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– 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

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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.
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
New Spartina shoots at Mumford Cove on May 8th 2015
A week after the first spawning moon of Atlantic silversides (M. menidia) at Mumford Cove, members of the lab and Dr. David Conover (SBU) are looking for silverside eggs.
A week after the first spawning moon of Atlantic silversides (M. menidia) at Mumford Cove, members of the lab and Dr. David Conover (SBU) are looking for silverside eggs.

[New Publication] Combining otolith microstructure and trace element analyses in Pacific bluefin tuna

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A new study published in the ICES Journal of Marine Science suggests that analyzing the trace elements incorporated into the otoliths of bluefin tuna may allow inferring the arrival of juvenile fish in the California Current Ecosystem

Juvenile Pacific bluefin tuna (PBT, Thunnus orientalis) are known to migrate from western Pacific spawning grounds to their eastern Pacific nursery grounds in the California Current Large Marine Ecosystem, but the timing, durations, and fraction of the population that makes these migrations need to be better understood for improved management. This new study published in the ICES Journal of Marine Science suggests that analyzing the trace elemental composition of bluefin tuna otoliths may divulge the time of arrival of the juvenile fish on the Californian Shelf. Scientists from the University of Connecticut, Stony Brook University, Texas A&M, as well as from NOAA collaborated in this effort, hoping to further develop this method to better inform managers in the future.

Citation
Baumann, H., Wells, R.J.D., Rooker, J.R., Baumann, Z.A., Madigan, D.J., Dewar, H., Snodgrass, O.E., and Fisher, N.S. (2015) Combining otolith microstructure and trace elemental analyses to infer the arrival of Pacific bluefin tuna juveniles in the California Current Ecosystem. ICES Journal of Marine Science 72:2128-2138.
Free PDF and HTML access

[Science Panel] 24th Annual Long Island Sound Citizens Summit

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“Combined effects of low oxygen and low pH on coastal marine organisms”

Save the Sound 24th Annual Citizen Summit

April 9th 2015. H. Baumann shared insights from experimental work on the combined effects of low oxygen and low pH on coastal fish and shellfish as part of a science panel discussion during the 24th Annual Citizen Summit organized by ‘Save the Sound’
The motto of the 24th Annual Citizen Summit, organized by Save the Sound was ‘Coming back from the brink’. Speakers highlighted the tremendous amount of work towards reducing the eutrophication problem of Long Island Sound, but also the challenges ahead. Baumann highlighted that in addition to traditional concerns of hypoxia as a negative consequence of eutrophication, acidification is a co-occurring stressor. The combination of these two stressors needs to be better understood and tested, because in ecology the effects of two co-occurring stressors may not simply be the sum of each stressor acting alone. Sometimes … 1 + 1 > 2. Other panelists were Dr. Jamie Vaudrey (UConn) and Lisa Suatoni (NRDC) moderated by Dr. Johan (Joop) Varekamp (Wesleyan University and Chairman of the Board, Connecticut Fund for the Environment).

Web: 24th Annual Long Island Sound Citizens Summit

[Campus Talk] H. Baumann talks at Avery Point Global Cafe

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“Nets versus Nature: Have we indadvertedly made our fish smaller?”

Global-Cafe-talk

April 9th 2015. H. Baumann contributed to Avery Point’s Global Cafe Series “The Omnivore at Sea” by talking about the topic of fisheries-induced evolution.
When hearing and talking about sustainable seafood, issues such as overfishing, fishing-related habitat destruction (e.g., trawls tearing through bottom habitat, dynamite fishing) or changes to the architecture of marine ecosystems (‘fishing down the foodweb’) often come to mind. Baumann talked about another potential effect of heavy decade-long commercial fishing, which is less clear but perhaps even more insidious. Nature’s age-old rule of survival in the ocean, i.e., that faster growing fish have better chances of survival, is suddenly reversed when size-selective fishing becomes the dominant agent of mortality. Because in fishing, a faster growing fish will just be susceptible sooner to get caught by the meshes of a fishing trawl. We instinctively know that life on earth has adjusted before to changing selection pressures, and there’s little reason to suspect that this case might be different. Commercial fishing may trigger fisheries-induced evolution, and this may mean smaller, earlier maturing fish and less total biomass for centuries to come. The brief talk will summarize the problem as we know it, explore alternative explanations and look at examples, which show that the issue is also inextricably linked to all the other natural and man-made changes (warming, food web) that affect fish stocks. A cautionary approach that considers evolutionary processes within the framework of sustainable fisheries is surely warranted.