Fish and Invertebrate Ecology

Principal Investigator

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.

Intern Logs: Tagging Sharks in the Sunshine State

by Claire Mueller


Selfie of three scientists with palm trees
Front to back: SERC interns Claire Mueller and Michelle Edwards, and SERC postdoc Chuck Bangley, explore windy Fort Pierce, Fla. 
(Credit: Claire Mueller/SERC)

As the communications intern for the Movement of Life Initiative, I’ve had the pleasure of doing a variety of fun projects, but my favorite was accompanying our marine team this winter to Fort Pierce, Fla., to continue their work with Harbor Branch Oceanographic Institute at Florida Atlantic University. Our mission was to tag as many bull sharks and cownose rays that we could with acoustic transmitters, allowing us to collect location data and determine the movement patterns of these two species.

When I arrived in Florida on January 14, I first caught up with Chuck Bangley, a postdoctoral fellow at the Smithsonian Environmental Research Center (SERC), and fellow SERC intern Michelle Edwards. They had been there since the previous Wednesday, and already had managed to tag four cownose rays and two bull sharks. Matt Ogburn (our fearless leader and principal investigator of SERC’s Fish & Invertebrate Ecology Lab) and Jay Fleming (the professional photographer documenting our expedition) joined the team on Monday night.

My favorite day of the week was undoubtedly Wednesday. We met at the boat at 6 a.m. to load up and trailer down to the lower St. Lucie River, where we’d try our luck catching our target species. The team was dragging a little—we’d had a long field day on Tuesday without too much excitement (only one small bull shark), and the morning temperatures were a little chillier than expected. But as we traveled to our first sample site and the sun began to peek out above the clouds, I began to get excited about the impending field day.

Scientists on boat
Christian Jones (left) hooks leaders onto the longline that intern Michelle Edwards (middle) passes to him. (Credit: Jay Fleming/Smithsonian)

When we arrived, we began the process of cutting up bait (usually mackerel and mullet) and organizing the boat to deploy the first longline. A longline is a long rope attached to two anchors, where we can clip on 50 baited hooks. Christian Jones, a visiting scientist from NOAA Fisheries, took the lead on setting the line, methodically clipping the hooks full of bait onto the anchored rope as it dragged from the boat.

After 30 minutes had passed, Christian hooked the float and began pulling in our catch. I was in charge of taking the leaders from the line and discarding the unused bait or handing off whatever was on the end to Michelle. She was in charge of measuring and processing the catch and reading the data out to Mike McCallister, the research coordinator for the Fisheries Ecology and Conservation Lab at Florida Atlantic University and captain of the boat that day. Within the first five leaders, we had caught bull sharks and catfish (not our target, but the individuals still need to be measured and weighed for the sake of the study).

To process the fish in the boat quickly, we tied off the longline to the boat and began tagging the two sharks we had in the tank on board. One shark was a little over two and a half feet (0.8 meters), the same size that we had been catching previously, while the other was nearly 5 feet (1.5 meters). I was able to tag both sharks’ dorsal fins and assist in measuring and weighing both. It may seem a little unnerving to work with bull sharks, typically revered as one of the most aggressive shark species, and before the trip I wondered what it would be like to work with this species. I found that once you get into the rhythm of prepping the shark for surgery and collecting data, you quickly forget about their supposed “aggression” and instead focus on how to tag the shark as quickly and efficiently as possible to lessen its time out of the water.

Two photos of scientists with live sharks on boat
Left: SERC biologist Matt Ogburn observes sharks in the onboard holding tank. Right: SERC interns Michelle Edwards (left) and Claire Mueller get ready to release a tagged bull shark. (Credit: Jay Fleming/Smithsonian)

Chuck was in charge of implanting the acoustic transmitters in the body cavity of the sharks. We put the sharks in a state of tonic immobility by turning them over, which has the same effect as anesthesia, but requires less time for the sharks to recover. The surgeries are quick, and afterwards the sharks are seemingly unfazed by their new accessory. Once released, each shark’s acoustic tag emits a unique signature that can be picked up by arrays of receivers along the East Coast of the United States as the shark journeys through through its seasonal migrations. The receivers can then download the shark’s location and send that info to the scientists who tagged the shark!

The rest of the day wasn’t nearly as exciting as the first longline sample, where we ended up catching five sharks. We only tagged three of them to speed the process of taking them off the longline and setting them free—when we start pulling up the longline we don’t have any idea how many sharks are hooked, so speed is key. Unfortunately we didn’t catch any more for the rest of the day, but overall it was a great to be out on the water working with these incredible creatures and getting to know my fellow scientists better. I’ve learned in my first years of conducting scientific studies that it’s not just about what you study, but who you study with that really makes the difference in what you get out of your science. Being in an environment that is quick to encourage and applaud, yet doesn’t hesitate to correct in a supportive way, is one of best ways to experience research in the field.

A huge thank you to both the SERC team and the Florida Atlantic University team for allowing me to tag along on this expedition! I’d also like to thank the graduate students of the Fisheries Ecology and Conservation Lab—Grace Roskar, Breanna DeGroot, Cam Luck and Rachel Shaw—for their patience and hospitality!

Seven scientists pose in front of Harbor Branch Oceanographic equipment
Shark tagging team, left to right: Claire Mueller, Michelle Edwards, Matt Ajemian, Matt Ogburn, Mike McCallister, Chuck Bangley and Christian Jones. (Credit: Claire Mueller/SERC)


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:

Welcome to the Educator Resources page-- below are a collection of lessons, web resources, and videos arranged by subject to help you quickly find resources in your interest area to create lesson plans or activities. Maryland follows the Next Generation Science Standards for K-12 science content standards. Access the Next Generation Science Standards broken down by topic at the National Science Teachers Association website.

Are you a teacher visiting SERC? Click here to learn more about how to prepare for your field trip to our campus and other general resources!

Discover, create, and share more resources and educational experiences on the Smithsonian Learning Lab!

Lesson: Movement of Life Initiative: Discover What Makes Sharks Move
Grade 4

Lesson: Sharks and Shorelines
Grades 6-10

Activity: Ecosystem Explorer | EARTH A New Wild
Grades 5-8

Reading/ Video: SERC’s Shorelines Blog "Following the Movement of Life: Tagging Sharks and Rays"
Grades 5-7

Reading/ Video: SERC’s Shorelines Blog "Tracking the Bay’s Cownose Rays"
Grades 5-7

For more information about shark migration, check out Smithsonian's Movement of Life Initiative!

Lesson: The Blue Crab's Chesapeake Journey
Grade 9-12

Video: SERC Scientists Video from the Smithsonian Science Education Center, “How do Scientists Track and Monitor blue Crab Populations in the Chesapeake Bay?
Grades 3-8


Video: SERC Ecosystems on the Edge video by one of our scientists, called “Blue Crabs: Top Predator in Peril”
Grades 3-8


Lesson: Juvenile Oyster Disease: A Growing Problem
Grade 9-12

Video: Determining the Resiliency of Juvenile Oysters in the Chesapeake Bay
Grade 3-8


Research Topics