A slick black head breaks the surface, drawing delighted shrieks from whale watchers in a growing, and lucrative, activity that some say should replace Iceland’s controversial whale hunt. Since their meager beginning in the 1990s, whale safaris in this island state have grown to attract tens of thousands of visitors each summer. But its proponents tensed up when Iceland reintroduced commercial whaling in 2006, and the two sides remain uneasy bedfellows.