April, 2015, marked the 12th consecutive year of an effort to map the Caribbean seafloor onboard the NOAA ship Nancy Foster. With nearly 1,324 square miles mapped since 2004, scientists from the National Ocean Service and their partners continue exploring the waters surrounding Puerto Rico and the U.S. Virgin Islands, identifying and mapping critical coral reef and fisheries habitat with sonar and video observations. Here are a few shots of the crew of the Nancy Foster, who make this mission possible.