FSU, Duke Partner to Study Impact of Gulf’s ‘Dead Zone’ on Shrimp Fishery

Florida State will serve as the lead institution for the collaborative project, which is funded by a four-year, $702,969 grant from the National Oceanic and Atmospheric Administration’s (NOAA) Northern Gulf of Mexico Ecosystem and Hypoxia Assessment Program.

Dead zones result from hypoxia (low oxygen) caused by algal blooms, which deplete the oxygen in water and render it unable to sustain animal life — a potentially catastrophic issue for the Gulf shrimping industry, estimated to be worth about $500 million annually. The Gulf of Mexico’s increasingly severe dead zone is one of the world’s two or three largest and the biggest one that affects a U.S. fishery. It forms in the late spring and summer off the coasts of Louisiana and Texas, covers between 7,500 and 8,500 square miles — roughly the size of New Jersey — and in some years stretches over nearly 12,500 square miles.

“Previous studies of hypoxia in the Gulf of Mexico have linked it to nutrient-rich runoff that fuels the algal blooms,” said marine ecologist Kevin Craig, a faculty member at The Florida State University Coastal and Marine Laboratory and a principal investigator for the study.

“Most of the nutrients seem to come from agricultural activities in the Mississippi River watershed, which drains 41 percent of the continental United States and includes major farming states in the Midwest,” Craig said. “Our research team intends to more effectively assess the likely effects of nutrient loading and hypoxia on fisheries, the associated economic costs of habitat degradation for fishermen and others who depend on coastal resources for their livelihoods, and the benefits of environmental policies to reduce nutrient pollution.”

Joining Craig is co-principal investigator Martin Smith, associate professor of environmental economics at Duke’s Nicholas School of the Environment and Earth Sciences. The study’s other participants are Lori Snyder Bennear, assistant professor of environmental economics and policy at the Nicholas School, and Jim Nance, a shrimp biologist at the National Marine Fisheries Service in Galveston, Texas.

“I’ve been working on the effects of the dead zone in both the Gulf of Mexico and in southeast U.S. estuaries for several years,” Craig said. “Most of my work has focused on the ecological effects of hypoxia. At Duke, Marty Smith has worked on the economic aspects but in other ecosystems. Ecology and economics are two disparate fields with very different cultures and approaches. Given the complexity of the problem in the Gulf, we decided to collaborate so that we could cover all facets of the dead zone’s consequences for the coastal ecosystem’s capacity to support fisheries.”

“Not much is known about the runoff’s economic effects on the shrimp fishery,” Smith said. “This research project will be the first direct investigation of these links.”

Regardless of the causes, Craig notes that hypoxia has substantial effects on the behavior of both shrimp and shrimp fishermen, forcing them to relocate to other areas. Smith points to changing economic conditions — including declines in real shrimp prices due to competition from imports and rising fuel costs that likely also have influenced the shrimp fleet’s behavior.

Craig and Smith agree that the dynamic nature of the interaction makes it difficult to measure the dead zone’s impacts based solely on the reported size of annual shrimp harvests.

To produce a more accurate measure of hypoxia’s impacts over large areas and extended periods of time, the researchers will collect and analyze data from a variety of sources and models, including aerial surveys of shrimping activity in waters around the dead zone.

Since the 1970s, the duration and frequency of dead zones have increased across the world’s oceans and can even be found in freshwater bodies such as Lake Erie.

For digital images, contact Craig at kevin.craig@bio.fsu.edu or (850) 697-8550.