Harmful Algal Blooms, Hypoxia, and Nutrients Research Webinar Series
Predicting the Biological Impacts of Hypoxia in Coastal Waters
Wednesday, October 7th, 2026 from 2:00 to 3:00 p.m. EST
This webinar will include two presentations:
Developing Dissolved Oxygen Criteria to Protect Propagation of Atlantic Sturgeon in the Tidal Fresh Delaware River
For decades, dissolved oxygen (DO) levels in the tidal-fresh Delaware River have been too low to support propagation of migratory fish, including the endangered Atlantic Sturgeon. In 2022, EPA determined that propagation of oxygen-sensitive migratory fish was an attainable use. Following an intensive period of method development and related policy development, EPA proposed new protective DO criteria in late 2023. EPA finalized the criteria in September 2025. This presentation will describe the physiologically-based cohort model and other aspects of the technical approach that EPA developed to support the rule.
Role of Movement and the Habitat Mosaic in Projecting Impacts of Dissolved Oxygen (DO) on Young-of-Year Atlantic Sturgeon
Hypoxia, or low dissolved oxygen (DO), is a water quality problem affecting coastal habitats. Increasingly, improved wastewater treatment has been effective in achieving improved oxygen levels in estuaries. Data quantifying the effect of hypoxia on aquatic life is useful in combination with quantitative models that improve estimates of the aquatic life benefits of potential nutrient management strategies. Modeling is especially important for fish, which are mobile and therefore have some ability to select habitats based on water quality. This presentation will discuss a spatially explicit individual based model (SEIBM) for Atlantic Sturgeon in the Delaware River, developed in the context of recent regulatory changes that aimed to reduce the extent and severity of hypoxia in the Delaware River to protect young-of-year cohorts of endangered sturgeon. Model results indicated that movement behavior can affect model predictions of biological responses to habitat improvements, including habitat tradeoffs between temperature and DO not considered in models that do not consider behavior.
Presenters and Moderator
Presenters:
Jim Hagy, EPA Office of Water
Dr. Hagy is a coastal environmental scientist in EPA’s Office of Water who has conducted scientific research and supported water quality management and policy development related to nutrients, eutrophication, and hypoxia in U.S. coastal waters. His research has addressed science and policy throughout the United States, with particular focus on Chesapeake Bay, the Gulf Coast, and recently Long Island Sound and the tidal-fresh Delaware River. Dr. Hagy’s recent work provided the technical basis for revised dissolved oxygen criteria for the tidal fresh Delaware River, which EPA promulgated in September 2025.
Rich Fulford, EPA Office of Applied Science and Environmental Solutions
Dr. Fulford is a Research Ecologist in the Gulf Coast Science Branch of OASES located in Gulf Breeze, FL. He has worked for EPA for 15 years specializing in ecological models that link human activity to coastal processes. His research has focused on fish energetics and included work in Lake Michigan, Chesapeake Bay, Tampa Bay, and the Gulf of America. In his spare time, Rich likes to travel and run triathlons. He received his Ph.D. in Zoology and Biomathematics from North Carolina State University.
Moderators:
- Brenda Rashleigh, EPA Office of Applied Science and Environmental Solutions
- Brenna Friday, EPA Office of Water
About the Webinar Series
Hosted by EPA, this free webinar series is focused on communicating the latest, cutting-edge research related to nutrients and the priority impacts of nutrient pollution: harmful algal blooms (HABs) and hypoxia.
Topics will include regional priorities; regulatory updates; and cutting-edge EPA research related to monitoring and forecasting, prevention, control, and response.
Webinars are typically held bimonthly from 2 to 3 p.m. ET on the last Wednesday of the month. Additional information and registration will be posted closer to the scheduled date and as they become available.
Past Webinar Recordings
Links to closed-captioned recordings of past webinars hosted on EPA's YouTube channel are available below. Certificates cannot be provided for watching the webinar recordings.