November 4, 2024 — For decades, Chesapeake Bay cleanup efforts have been driven by a simple equation: Cleaner water equals more fish and shellfish.
The 1983 Chesapeake Bay Agreement, which launched the state-federal restoration effort, made that clear as it sought to reverse the Bay’s “historical decline in the living resources.” It would do so, the agreement said, by addressing pollution flowing into the Bay.
The living resources goal was reiterated in the next two cleanup agreements in 2000 and 2014, and the pollution goal aimed at making it happen has been refined to measurable targets for reducing nutrient pollution in the water.
But would achieving those goals actually result in more fish, crabs and oysters?
It’s complicated.
Bay scientists caution that the link between nutrient reductions and increased fish abundance is highly uncertain. In a report last year, they warned of a need for “grounding” the public’s expectations about the recovery of aquatic life even if cleanup goals are met.
In the May 2023 Comprehensive Evaluation of System Response (CESR) report, the Scientific and Technical Advisory Committee of the state-federal Chesapeake Bay Program cautioned that other factors — such as temperature, salinity, river flows and structural habitats — play important roles in determining fish abundance. Compared with those, the water quality role can be small.
“Considerable uncertainty,” they wrote, “will accompany any effort to predict how fish and shellfish populations respond to changes in water quality alone.”