The Chesapeake Bay is home to more than 3,600 species of plants and animals. That includes 348 species of finfish, 173 species of shellfish, and more than 16 species of underwater grasses. It’s a vibrant ecosystem that has supported healthy fisheries for a long time. It has provided people with lots of great seafood, and supported many people who make a living in the seafood industry.
But climate change is affecting Chesapeake Bay habitats and, in turn, the species that rely on them. As habitats change, some species find challenges, while others may see opportunities.
We are already seeing some changes in the Chesapeake Bay. Sea level rise brings salt water to marshes that aren’t used to higher salinity. Plant and tree species that can’t migrate to less salty, newly inundated areas die. Grasses and other herbaceous plants stand a better chance of migrating, unless they run into a barrier like a road or housing development.
Submerged underwater grasses like eelgrass, which juvenile crabs need as habitat, are also affected by warming waters. The range of where those grasses can live is shifting. Rising water temperatures cause fish and other species including shrimp to shift north to find cooler water.
Increased temperatures, changes in precipitation patterns, and rising sea levels can cause hypoxia, or areas of very low or no oxygen. Hypoxia pushes fish away in search of more oxygen and kills immobile shellfish.
Intense rainfall events, which are more frequent due to climate change, can lower salinity in affected areas. Different fish prefer different salinity levels, and low-salinity areas can encourage the spread of fish that prefer fresher waters, like invasive blue catfish.