The introduction of nonnative species to coastal U.S. ecosystems has profound environmental effects. Invasive algae and non-native fishes are wreaking havoc with Hawaiian coral reefs. Zebra mussels have overwhelmed native shellfish populations in the Great Lakes, and the European green crab has been showing up in alarming numbers in the Northeast, where it competes more successfully than native crabs for local resources. These are just a few of the problems that coastal resource managers currently face.
To address the problem, CCMA's Coastal Ocean Assessment Status and Trends Team is conducting bioeffects assessment studies to examine species ecology in coastal waters and estuaries that are being impacted by invasive species. Many scientists believe that the occurrence of the non-native Asian clam Potamocarbula amurensis in San Francisco Bay was first recorded during a CCMA sediment toxicity assessment study. Amazingly, out of 530 species identified in San Francisco Bay, more than 240 are reportedly nonnative. Some of these nonnative species have dominated the local benthic biomass. CCMA's ongoing study of this estuary will shed more light on how this ecosystem has changed over time, and may help address similar problems in other areas of the country.