Southern Flounder Symposium

Southern flounder have evolved a complex life history strategy that includes continental shelf spawning, long larval duration (45-60 d) and advection into estuarine nursery habitats, followed by spatially variable benthic settlement, an early shift to piscivory, and rapid growth to maturity.  Several aspects of their life history remain poorly understood, with impacts on our ability to model stock dynamics and identify the most appropriate management strategies.  This presentation will describe the major features of southern flounder life history, focusing specifically on features for which knowledge has advanced in recent year, as well as features about which understanding remains poor.  These will include ocean spawning locations, larval delivery to estuaries, settlement dynamics, sources of mortality in the estuary, habitat use/migration timing, variation in maturity scheduling, and the extent of ocean residency by adults.  Each of these has the potential to contribute to the spatial scale of stock mixing in both the Atlantic and Gulf of Mexico, and to inform our ability to accurately model southern flounder stock dynamics and promote effective management.

Presenter

Dr. Fred Scharf
Professor of Fisheries Biology
Department of Biology and Marine Biology
University of North Carolina - Wilmington 

Dr. Scharf earned his PhD in Wildlife and Fisheries Conservation from the University of Massachusetts, Amherst in 2001 and joined the faculty in the Department of Biology and Marine Biology at UNCW in January 2003, where he teaches undergraduate courses in animal biodiversity and fisheries biology, and graduate courses in biostatistics, population dynamics, and fisheries science. Dr. Scharf’s research program at UNCW has been focused on the population dynamics of marine and estuarine fishes, including the study of recruitment processes, the estimation of mortality rates, fish reproductive dynamics, and behavioral ecology, particularly movement and migration. Research findings have been published in several journals, including the Journal of Fish Biology, Marine and Coastal Fisheries, ICES Journal of Marine Science, Transactions of the American Fisheries Society, Marine Ecology Progress Series and the Canadian Journal of Fisheries and Aquatic Resources. As a faculty mentor, Dr. Scharf has supervised the thesis/dissertation research of more than 20 UNCW graduate students, including 5 doctoral students. He is an active member of the American Fisheries Society, hosting conferences in Wilmington in 2009 and 2011, serving as President of the Tidewater Chapter, and officer roles with Early Life History Section and the Southern Division.  He has provided extensive service to both state and federal fisheries management, chairing advisory committees for the North Carolina Division of Marine Fisheries, and currently serving as the Vice Chair of the South Atlantic Fishery Management Council’s Science and Statistical Committee. In 2013, Dr. Scharf received the award for Excellence in Fisheries Education from the American Fisheries Society, and was named to the inaugural class of American Fisheries Society Fellows in 2015.
 

Habitat characteristics can have a strong impact on overall populations of coastal fish. This is especially true for juvenile survival, where habitat quality may impact refuge availability, food availability, and other aspects of growth and survival. Juvenile mortality is a significant determinant of many fish populations and is often dependent on availability of favorable environments. In this presentation we will examine flounder use of various habitats, characteristics of these habitats affecting survival and growth, how they vary along North Carolina’s coastal regions, and factors affecting habitat quality. We will also look at direct and indirect impacts of varying water quality. The emphasis will be on juvenile / subadult flounder habitat and changes in distribution with growth. 

Presenter

Dr. Martin Posey
Professor of Biology and Marine Biology
University of North Carolina Wilmington 

The coastwide stock assessment for southern flounder (Paralichthys lethostigma) indicates a need to better understand offshore migration and movement patterns. Collaborative research between the North Carolina Division of Marine Fisheries and the University of North Carolina Wilmington uses two Pop-Up Satellite Archival Tag (PSAT) models to identify offshore spawning locations and timing of spawning movements for southern flounder. Tagging efforts occurred in 2020-2023 with tags released primarily throughout North Carolina and a subset of tags released in South Carolina. Female southern flounder were captured using commercial pound nets, hook-and-line, gill net, and dependent sampling gears. Results of PSAT releases indicate that while some fish migrate out of the estuaries to inner and outer shelf habitats, others remain inshore. Temperature and depth data suggest that fish migrating to outer shelf habitats fluctuate between depths across short periods, which may be indicative of spawning behavior found in other flatfish species. Deviances between the timing of individual migrations highlight the potential variability and complexity of movement patterns. A better understanding of southern flounder migration patterns and offshore spawning habitats and behaviors will provide valuable information for the spatial management of the South Atlantic population and offer avenues for future research on histology and reproduction of southern flounder. 

Presenter

Dr. Shelby B. White
Marine Business Specialist
Virginia Institute of Marine Science
William and Mary

Dr. Shelby White is the Marine Business Specialist at the Virginia Institute of Marine Science in Gloucester Point, VA where she serves as a liaison for various industries, including commercial and recreational fishing, seafood processing, aquaculture, and working waterfronts. She grew up both commercial and recreational fishing in northeastern NC and her interest in fisheries has continued throughout her academic and professional career. She recently graduated with her PhD in Fisheries Science from VIMS, which focused on participation and diversification in Virginia’s commercial fisheries. Shelby also has an extensive background in marine biology and has worked at the Division of Marine Fisheries as an intern, technician, biologist, and social research scientist over the years. During her time as a biologist, Shelby conducted satellite tagging research on southern flounder through a Commercial Fishing Resource Fund grant.

Southern flounder has been the most valuable finfish fishery in North Carolina but is currently overfished. A challenge for management is that the location of its offshore spawning grounds is unknown. To address this, we applied a multifaceted approach to investigate the species’ offshore migration and spawning habitat: 1) Acoustically tagged flounder were tracked with inshore and offshore receivers and a wave glider; 2) A hydrodynamic model back calculated larval fish dispersal pathways to potential spawning habitats; 3) DNA barcoding identified fish eggs collected during surveys of potential spawning habitat; 4) Fish ear-bone microchemistry was used to determine migration histories since certain chemicals serve as proxies for salinity; 5) Reproductive staging assessed where and when fish were preparing to spawn. Collectively, these techniques generated convergent answers to questions about behavior. We learned there is substantial behavioral variability between individuals. Fish tagged at the same location on the same date exited sounds through diverse pathways. Emigration timing may vary between southern and northern estuaries in North Carolina since our study detected later emigration than previous research from the southern part of the state. Examination of gonads revealed batch spawning occurs and a portion of the population are spawning capable prior to offshore emigration in late October/November. Both tagging and egg surveys suggest that some spawning may occur near the edge of the continental shelf, but other fish spent substantial time on the inner shelf where flounder eggs were also detected. The hydrodynamic model indicated that many larvae originated from a potential spawning “hotspot” in coastal, southern Onslow Bay. This model also suggested episodic connectivity with populations as far south as Florida. After overwintering, some fish moved shoreward and were detected again at North Carolina Inlets, while other fish traveled as far south as Georgia. Return of some fish to the sound after overwintering offshore was also confirmed via ear-bone microchemistry. A small segment of tagged fish appeared to overwinter near North Carolina inlets, likely without traveling offshore. Lastly, gonadal examination indicated that only fish collected from offshore waters in summer showed signs of previous spawning. Given the diversity of behaviors, more research is needed to understand which behavioral modes are most common and if certain habitats should be protected to conserve this species.

Presenter

Dr. Rebecca Asch
Assistant Professor
East Carolina University

Established in 2014, the North Carolina Division of Marine Fisheries (NCDMF) Multi-Species Tagging Program is a comprehensive tag-return study designed to collect more accurate information on North Carolina’s marine finfish species. Tagging animals is one successful method researchers can use to monitor fish and wildlife populations. Scientists track animals on land, through the air, or in the water using a variety of tagging techniques. Tracking fish and other marine animals is very important when managing populations, but it also has its challenges. Aquatic organisms spend most of their time underwater, hidden from visual observation, which makes researching them quite difficult. Tagging—the process of marking and recapturing an animal—provides important information about the life history of fish that researchers would otherwise be missing. When a fish is tagged, released, and then recaptured later, the information collected provides managers with insights on migration patterns, habitat use, population structure, and mortality rates. The success of tagging programs comes from public participation by reporting a tagged fish or helping to tag fish. Through collaborative efforts by Division staff, state and federal agencies, university researchers, and public volunteers within the fishing community, the Multi-Species Tagging Program tags over 15,000 Striped Bass, Red Drum, Southern Flounder, Spotted Seatrout, and Cobia each year. Tagging programs play a vital role in tracking fish movements and populations, but it’s also an opportunity for the fishing community to get involved in scientific research and contribute to the management of North Carolina’s coastal resources. 

Presenter

Ami Staples
Conservation Biologist II
N.C. Division of Marine Fisheries

Ami Staples is the Marine Fisheries Biologist II for the Multi-Species Tagging Program at the North Carolina Division of Marine Fisheries (NCDMF). Ami oversees all aspects of the Tagging Program from administration and research to public engagement and outreach. Her favorite part of the job is tracking fish movements and working directly with the fishing community. Ami is always eager to speak to an angler about their tagged fish recapture, lead engaging presentations about the Tagging Program to fishing clubs, train volunteers on how to tag fish and collect scientific data, or conduct hands-on science activities for school groups.

Originally from Georgia, Ami received her B.S. in Fisheries and Wildlife Management and M.S. in Forest Resources from the University of Georgia. Ami has a passion for science communication and is a published author and illustrator. When not at work, Ami spends most of her time outdoors and her favorite spot is fishing on the dock with her husband, two daughters, and four cats. 

Presenter

Dr. CJ Schlick
Stock Assessment Scientist
NC Division of Marine Fisheries

Presenter

John Carmichael
Executive Director
South Atlantic Fishery Management Council 

John Carmichael is the Executive Director of the South Atlantic Fishery Management Council. He has worked at the Council since 2003, originally as Program Manager for the SEDAR assessment process and later as the Deputy Director for Science prior to becoming Executive Director in 2020. Previous positions include serving as a stock assessment scientist with the NC Division of Marine Fisheries working with striped bass, red drum and river herring; an FMP coordinator with the Atlantic States Marine Fisheries Commission; and a biologist with the Maryland Department of Natural Resources. He has a BS in Fisheries and Wildlife from Virginia Tech and an MS in Zoology from NC State.