Climate Number: 217 miles
Along America’s East Coast, blue mussels (Mytilus edulis) have traditionally been an important food source for larger species. They are also commercially farmed and even help improve water quality by filtering out pollutants as they feed. As recently as 50 years ago, blue mussels could be found as far south as the waters around Cape Hatteras, N.C. Yet, these species, like all species, have a thermal limit, meaning that once water and air temperatures reach certain levels, the animals die. Air and water temperature increases over the past 50 years along the Mid-Atlantic coast have pushed blue mussel populations farther north. At low-tide, the mussels are exposed to the open air. Multiple exposures to air temperatures of 89.6 degrees or greater kill the mussels and these types of conditions are now more common than they were 60 years ago. As temperatures have warmed, the mussels have retreated north. Now, intertidal blue mussels are not found south of Lewes, Del., indicating a northward shift in the southernmost extent of their range by about 217 miles.
For comparison: 217 miles is also about the same distance (as the crow flies) between Syracuse, N.Y. and Philadelphia, Pa.; Detroit, Mich. and Cincinnati, Ohio; or Los Angeles and Monterey, Calif.
Seasons: Spring, Summer, Fall
Sources: Jones, SJ et al. “Rising environmental temperatures and biogeography: poleward range contraction of the blue mussel, Mytilus edulis L., in the western Atlantic.” Journal of Biogeography. Published Online 19 August 2010, DOI : 10.1111/j.1365-2699.2010.02386.x and Science Daily. “Too Hot to Handle: Impacts of Climate Change on Mussels.” 19 August 2010. Accessed Online 25 August 2010
