Oceans and coastal ecosystems support an incredible diversity of fish and invertebrates that have sustained human societies for millennia through fisheries and aquaculture. These species are key players driving ecosystem structure and function, but human activities threaten the productivity and diversity of marine life. In the Anthropocene, finding a balance between harvest and conservation of fish and invertebrates, and mitigating other human impacts on marine ecosystems, will be key to sustaining productive, resilient, and biodiverse coastal and marine ecosystems. We address broad problems of population and community ecology using long-term quantitative sampling, animal behavior/movement studies, and innovative experiments at multiple spatial and temporal scales. Our studies analyze human impacts and natural change in freshwater, estuarine and marine systems.
Double Trouble? Tracking the Growth of Young Oysters Stressed by Acidity and Low Oxygen
by Cosette Larash
The eastern oyster (Crassostrea virginica) is one of the most important species in Chesapeake Bay. These shellfish filter the water, their reefs provide shelter for other marine species, and they’re an important seafood resource. But their numbers have hit a historical low due to overfishing, diseases like Dermo, and stressors such as hypoxia (low dissolved oxygen) and acidification (low pH).
Biologists with the Smithsonian Environmental Research Center (SERC) want to find out whether the double stresses of low oxygen and acidification can stunt oyster growth. Studies have shown that juvenile oysters grown under low oxygen are generally smaller than oysters grown under normal oxygen conditions. However, scientists still don’t know how these oysters fare over the long term. The answers could help aquaculture farms and oyster restorations all over the Chesapeake adapt to the often extreme conditions beneath the surface.
“We are especially interested in looking at how exposure to both of those stresses early in life can lead to effects later in life,” said Matt Ogburn, a SERC marine ecologist.
SERC’s Marine & Estuarine Ecology Lab is running the experiment, with an assist from the Fish & Invertebrate Ecology Lab. The experiment has two main components: lab work and planting oysters in Chesapeake Bay.
Starting in May 2017, the biologists raised oysters in SERC’s laboratory and exposed them to various dissolved oxygen and pH concentrations. The treatments ran for five days a week, over an eight-week period. For the biologists, it’s critical to study low oxygen and acidity individually as well as together, to understand how each type of stress affects the oysters. Before deploying the oysters in the field, the scientists glued the oysters to tiles and snapped a picture of them, so they could track individual oyster growth rates throughout the experiment.
Once the oysters were glued and photographed, they were ready to be planted. The team deployed the oysters at four different stations in the Chesapeake Bay in July, and left them there for about three months. In October, they collected the oysters and began checking their growth in the lab. For each oyster, they’re measuring both shell length and shell area, weighing the shell and tissue separately, and snapping another photo.
With over 1500 oysters sent out into the field, SERC’s team is still analyzing data, but they expect to have results during 2018. “We’ll share those results with the both the aquaculture community and restoration community,” said Ogburn. “We think the results of this project will help inform how oysters are raised early in life history, to better condition them to survive when they are planted out into the Bay.”
Funding for the research was provided by Maryland Sea Grant and the Smithsonian Institution.
Understanding the ecology of fisheries is critical to maintaining resilient, productive and biodiverse coastal and marine ecosystems. Fishing is an important sector of coastal economies, provides an important supply of food for human societies, and is an activity of great cultural and historical importance. But fisheries have also contributed to the decline of coastal and marine ecosystems through changes in biomass and community structure, disruption of food webs, and alteration of habitats. Using the Chesapeake Bay as a model system, we are addressing fisheries issues including the impacts of harvest, restoration, and conservation on populations, communities and ecosystems, habitat use, migrations and connectivity with other coastal ecosystems. To learn more about our fisheries ecology and conservation research, please visit the following webpages:
Our long-term studies of fish and invertebrate communities in the Rhode River, Maryland study site offer a window in the community structure and population dynamics of fish and invertebrate communities in one of the most productive ecosystems on earth, the Chesapeake Bay. Spanning more than three decades, this research tracks seasonal, annual, and decadal variation in species composition and abundance of fishes and macro-invertebrates. Sampling methods include trawling, seining, a fish weir, benthic infauna cores, and tethering experiments. The long-term descriptive data, in combination with our experimental studies, provide an unusual database for exploring populations, communities, predator-prey relationships, impacts of fisheries, and impacts of environmental variability and climate change, and other ecological processes. To learn more about our long-term research, please follow the links below:
Many species on the planet migrate during their lifetime, using different habitats during specific life stages. What habitats are most important and why? How will climate change affect migrations? What are the benefits and costs of migration to individuals? How can we best manage fisheries for migratory species? How do migratory species affect community structure and ecological processes? To learn more about our Movement of Life Initiative research, please visit our Movement of Life Initiative webpage:
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Lesson: Sharks and Shorelines
Activity: Ecosystem Explorer | EARTH A New Wild
Reading/ Video: SERC’s Shorelines Blog "Following the Movement of Life: Tagging Sharks and Rays"
Reading/ Video: SERC’s Shorelines Blog "Tracking the Bay’s Cownose Rays"
For more information about shark migration, check out Smithsonian's Movement of Life Initiative!
Lesson: The Blue Crab's Chesapeake Journey
Video: SERC Scientists Video from the Smithsonian Science Education Center, “How do Scientists Track and Monitor blue Crab Populations in the Chesapeake Bay?
Video: SERC Ecosystems on the Edge video by one of our scientists, called “Blue Crabs: Top Predator in Peril”
Lesson: Juvenile Oyster Disease: A Growing Problem
Video: Determining the Resiliency of Juvenile Oysters in the Chesapeake Bay