shonnard's 99-year lease began an era in which walker's cay was a well-known sport fishing location. one of walker's cay's seasonal residents was american businessman robert abplanalp, the inventor of the modern-day aerosol valve for spray cans. abplanalp bought the lease on the island in 1968 and continued to develop it as a sport fishing destination, not neglecting to pay attention to the conservation of marine life; he began encouraging tag-and-release fishing in the early 1970s. walker's cay was particularly known as a location for billfishing, with huge atlantic blue marlin caught in the area; angling for bonefish was also popular there.