It is my understanding Tigermusky is a hybred. It is a cross between Musky and Northern Pike so they are steryl by nature. They were planted in Mayfield to control the Squaw fish population. Within 5 years the average Squaw fish went from 14 inches to 7. The average life span of the Tigermusky is 5 to 7 years. They were planting about 100 new fish each year. I don't know if they still are. But all they have to do quit planting and they will eventually go away