They found that damaged ruffe skin emits an odor, or alarm pheromone, repugnant to other ruffe that dramatically suppresses their swimming and feeding activities. Clearly, this cue has potential for managing ruffe. Fish commonly use pheromones to coordinate activities, such as mating and schooling, in waters that are often turbid, vast, and relatively featureless.
Alarm pheromones signal the presence of potential danger.
They have given up for lack of ideas or funding. Authorities in Alpena, Michigan, have approached Sorensen about using the alarm pheromone to exclude ruffe from areas where they are not wanted, such as docks where ships take on ballast water. Sorensen has also identified a ruffe sexual attractant that might be used in conjunction with the alarm pheromone. Presumably, they crossed the Atlantic Ocean as accidental passengers in the ballast tanks of cargo ships. Within a decade of their detection, Eurasian ruffe became the most abundant fish trawled from the bottom of the harbor.