The benefits gained from local measures to restore water quality and improve valuable fisheries may be strongly affected by regional restoration efforts according to a new study by researchers from Smithsonian Environmental Research Center and their colleagues from University of Virginia, Louisiana State University, and University of Maryland.
By taking a broad look at the ecology and economics within the Chesapeake Bay system, the researchers have shown that regional restoration efforts may alter the benefits of local efforts. Regional nutrient management efforts may be required for stakeholders to reap anticipated benefits and maintain their support and willingness to pay for restoration.
As an example, Dr. Denise Breitburg, the lead author of the study, sites the impact of reducing nutrient discharge into the Patuxent from within the Patuxent watershed. “Nutrient management at the local level substantially improved chlorophyll concentrations in much of the river, but had virtually no effect on dissolved oxygen in the deeper waters of the river,” she said, “Hypoxia [low dissolved oxygen] in the deeper waters was almost entirely controlled by water coming in from the mainstem of the Chesapeake Bay.” Low dissolved oxygen can negatively impact such things as fish larvae survival and recreational fishing catches within the river. Because fishers can choose the location they visit based on expected catch rates, the economic gain from recreational fisheries that derives from local improvements in water quality is minor compared to those from regional water quality improvements.
According to the researchers, a disconnect between local and regional efforts has the potential to jeopardize restoration plans if not understood and taken into account. “Managers and stakeholders need to know what to expect for their efforts,” Breitburg said. “Regulations that decouple the timing or magnitude of local and regional restoration efforts may alter benefits, willingness to pay, and stakeholder political support for restoration.”
The scientists combined five different models to analyze the impacts of both local and regional actions. Their analysis considered the impact of land use practices on nutrient discharge; impacts of water quality in the main bay on the waters of the Patuxent River; effects of dissolved oxygen level on survival of bay anchovy eggs and larvae; the potential combined benefits of nutrient reduction and oyster restoration; and effects of changes in water quality on the economic value of fisheries within the river.
Breitburg will present results of this group project in a talk at the four-day Estuarine Research Federation conference in Norfolk, Virginia, on Friday, October 21.
For information about attending the meetings see: http://erf.org/meetings.html