ANNAPOLIS, Md. — As record-breaking water temperatures continue to stress the Chesapeake Bay and its tributaries, scientists are calling on residents and policymakers to take immediate steps to protect vulnerable fish populations.
Recent fish kills in the Potomac River and Baltimore Harbor have underscored the growing threat posed by extreme heat. A portion of the Potomac reached 94 degrees this week, while rapid temperature and oxygen fluctuations in Baltimore Harbor led to another significant die-off.
“Summer is a stressful time to be a fish in the Bay,” said Chesapeake Bay Foundation Maryland Staff Scientist Gussie Maguire. “Most of our native species prefer cooler, more moderate water temperatures. But extreme weather and climate change are threatening those ideal conditions and making life for fish much more dire.”
Striped bass, one of the Bay’s most iconic species, are particularly vulnerable. Heat stress often leads to high mortality rates among caught-and-released fish during summer months. In response, the Maryland Department of Natural Resources recently closed striped bass fishing for the entire month of August and advises anglers to check forecasts and avoid targeting rockfish when air temperatures exceed 90 degrees.
In the upper freshwater reaches of the watershed, native brook trout require stream temperatures below 70 degrees to survive. Increased stormwater pollution from hot pavement and intense storms further endangers these cold-water habitats.
The Chesapeake Bay Foundation recommends several practical actions to help fish beat the heat:
- Reduce stormwater pollution by managing runoff from roads, sidewalks, and developed areas. Climate change is intensifying this problem through alternating drought conditions and heavy rain events.
- Prioritize trees along rivers and streams. Forest buffers absorb polluted runoff and provide essential shade to keep water temperatures lower.
- Give striped bass a break during hot summer months. Anglers can target other species without summer restrictions, such as invasive blue catfish.
“Wildlife is incredibly resilient, but they sometimes need a helping hand,” Maguire added. “As extreme heat and intense summer storms become more common, let’s not forget about our fish friends and help them however we can.”
While early summer monitoring showed higher dissolved oxygen levels due to drought conditions, July’s consistent high temperatures and storms are now taking a toll. The Moore-Miller Administration continues to invest in watershed restoration, including recent grants for ecological projects and mussel propagation efforts.
As summer heat persists, the Chesapeake Bay Foundation is urging states, local jurisdictions, and residents to work together to keep waters cool and reduce heat stress on the Bay’s fish populations. Simple actions by individuals can contribute to meaningful protection for this vital ecosystem.
