Over the last 30 years, monitoring in rivers around the North Atlantic Ocean has confirmed that there has been a significant decline in overall marine survival of Atlantic salmon. The reasons for this are not yet clear, but Canadian scientists, along with their counterparts in the U.S. and Europe, are working on finding the answers. The science surrounding salmon conservation has become a primary focus for the North Atlantic Salmon Conservation Organization, or NASCO – a regional fisheries management body to which Canada belongs.